Using human-imprinted pheasant ( Phasianus colchicus ) chicks to investigate farmland foraging potential

Gwendolen Elizabeth Hitchcock

A thesis submitted for the degree of Doctor of Philosophy of Imperial College London , Department of Life Sciences, Division of Biology

March 2010 ABSTRACT

Pheasant chicks, like many other farmland birds, require a large proportion of invertebrates in their diet for successful growth and development during their first few weeks. This study used human-imprinted pheasant chicks as a novel sampling tool to investigate which arable habitats provided the best foraging. Using human-imprinted chicks decreased sampling bias and allowed a biologically relevant method of assessing invertebrate availability within each habitat. Faecal analysis was used to identify which invertebrates were eaten and correction factors established to take into account the differing digestion rates of different fragments. The validity of using commercially farmed chicks for this study was confirmed by the comparison of wild and farmed strain chicks.

The value of non-cropped areas, both long-term set-aside and crops planted for game cover, in terms of diet and cover is confirmed. Greater proportions of preferred prey groups were consumed in both types of set-aside than in the commercial crop fields. Interestingly, no difference was found between spring and winter sown cereals and non-cereal crops. The long-term set-aside areas were found to be particularly beneficial to foraging birds as their vegetation structure allowed easy access to potential prey items.

As farming has intensified, many farmland birds, which also require invertebrates during their early stages, have declined. If the diet of imprinted pheasant chicks is comparable to those of other farmland birds this method could be used to accurately assess benefits to avian conservation on a wider scale. Human-imprinted grey partridge foraging with pheasant chicks showed similar behaviour and ate similar insects indicating that habitats benefiting one are likely to benefit the other. Faecal samples collected from wild broods of other farmland birds - the skylark, yellow wagtail and lapwing - showed certain similarities in dietary preference implying that careful comparisons may be made.

2 DECLARATION

I confirm that this thesis is my own work with the exception of Chapter 7 where the research was conducted together with two MSc students, Claire Whittington and Zoe Pittaway, under my supervision.

Signed: ...... G Hitchcock ......

Date: ...... 10/03/2010 ......

3 ACKNOWLEDGEMENTS

To begin with I would like to thank Imperial College London, the Game and Wildlife Conservation Trust (GWCT), Graf. Hardegg and the BBSRC for funding my research; also my supervisors, Dr Simon Leather, Dr Rufus Sage and Professor Jim Hardie, for their help and support throughout. Especial thanks goes to Graf. Maximilian Hardegg for inviting me to use his estate for my fieldwork and for providing accommodation, transport and equipment. To all the staff at the Seefeld estate my eternal gratitude for welcoming me and helping me settle in a new country. In particular thanks to Karl Pock, without whom this project would have been impossible, thank you for being my first port of call in any incident – from finding bamboo canes field markers to explaining my work to the border police!

My thanks to Roger Draycott and Dave Butler for their help in setting up this project, their combined knowledge of the Seefeld estate and imprinting was irreplaceable. Thanks to Steve Moreby and the entomology laboratory at the GWCT for teaching me the basics of faecal fragment identification and bearing with me until I could tell the differences between insect legs! Also thanks to Donald Quicke (Imperial College) and Jon Flanders (University of Bristol) for further assistance with the identification of faecal fragments. To Nicholas Aebischer (GWCT) and Tilly Collins (Imperial College) thank you for your patience whilst helping me to understand the complexities of statistics whilst struggling my way through my results.

To Claire Whittington and Zoe Pittaway, I cannot thank you enough for your assistance in the field and, more importantly, your friendship. My thanks to Andrew Hoodless and Richard Dale for their many patient hours in the field helping us to find wild nests and broods. Also thanks to Fransisca Sconce, Mimi Sun and Laurence Livermore for assisting with laboratory work and to Sam Jervis for his support and assistance in the field.

Last but by no means least my thanks to Diane Hitchcock and Vicky Levett for proof- reading this thesis and patiently correcting my spelling and grammar – I owe you one! Thank you to all my family and friends for their love and support, especially my parents, Keith and Diane, and my partner Mark.

4 CONTENTS

Abstract 2 Declaration 3 Acknowledgements 4 Contents 5 Tables and figures 7 1 Introduction and background information 11 1.1 Farmland as a natural resource 13 1.1.1 Detrimental effects of the intensification of agriculture 14 1.1 .2 Can agri -environment schemes benefit farmland birds? 16 1.2 Natural history of the Pheasant ( Phasianus colchicus ) 20 1.2.1 Taxonomy and distribution 20 1.2.2 Ecology and habitat use 22 1.2.3 Why are pheasants important? 24 1.3 Study aims 25 2 Study site and general methods 27 2.1 Study site 27 2.2 Chick foraging trials 33 2.2.1 Imprinting 34 2.2.2 Field trials 36 2.2.3 Faecal collection and analysis 37 2.3 Invertebrate sampling 38 2.4 Vegetation survey 40 3 Differential recovery of invertebrate fragments 42 3.1 Introduction 42 3.2 Methods 44 3.2.1 Correction factors 46 3.3 Results 46 3.3.1 Correction factors 59 3.4 Discussion 52 4 The diet and foraging behaviour of farmed and wild strain human- imprinted pheasant chicks 54 4.1 Introduction 54 4.2 Methods 56 4.2.1 Diet 57 4.2.2 Behaviour 58 4.3 Results 58 4.3.1 Diet 58 4.3.2 Behaviour 62 4.4 Discussion 65 5 The diet of pheasant chicks foraging in different arable habitats 68 5.1 Introduction 68 5.2 Methods 71 5.2.1 Diet 72 5.2.2 Vegetation 73 5.3 Results 74 5.3.1 Invertebrate sampling and chick preference 75 5.3.2 Foraging in different commercial crops 77

5 5.3.3 The benefits of non-crop areas to pheasant chicks foraging in arable farmland 83 5.3.4 Comparison of long-term set-aside and game crop schemes 92 5.4 Discussion 99 5.4.1 Insect sampling methods 99 5.4.2 Preferred prey items 100 5.4.3 Beneficial farmland habitats 101 6 Dietary and behavioural comparison of human-imprinted grey partridge and pheasant chicks 105 6.1 Introduction 105 6.2 Methods 107 6.2.1 Diet 108 6.2.2 Behaviour 109 6.3 Results 109 6.3.1 Diet 109 6.3.2 Behaviour 111 6.4 Discussion 11 3 7 The habitat use and diets of skylark and lapwing chicks sharing arable farmland with breeding pheasants 116 7.1 Introduction 116 7.1.2 Skylarks on arable land 119 7.1.3 Lapwings on arable land 121 7.2 Methods 122 7.2.1 Breeding skylark territories 122 7.3.2 Diet of wild farmland birds 124 7.3 Results 12 8 7.3.1 Skylark territories 12 8 7.3.2 Diets of wild birds 130 7.4 Discussion 13 8 7.4.1 Skylarks breeding on arable farmland 139 7.4.2 The diets of wild chicks compared with human-imprinted pheasant chicks 140 8 General discussions 143 8.1 The methodology of using human-imprinted pheasant chicks 143 8.2 Arable habitats beneficial to foraging pheasant broods 145 8.3 Potential application for other species 14 6 8.4 Management suggestions 149 8.5 Further research 150 8. 6 Conclusions 151 9 References 152 Appendix I. Flora of the Seefeld estate 168 Appendix II. Birds of Seefeld estate 170

6 TABLES AND FIGURES

List of tables

3.1 Quantities of invertebrates used during feeding trials and the diagnostic fragments that can be obtained from each with the number of fragments per individual. 45 3.2 Number of fragments recovered at 18 hours compared with 24 hours. 47 3.3 Correction factors (f) to be used in dietary reconstruction. 51 4.1 Ranking matrix of the relative differences between the diets of imprinted (2007 – 2008) and wild (2001 – 2002) pheasant chicks. 61 4.2 Summary of the GLM investigating factors affecting the distance of imprinted pheasant chicks from their human handler. 63 4.3 Summary of the GLMs investigating factors affecting the distance of imprinted pheasant chicks from their human handler at different time intervals. 64 5.1 Seed mixes sown as potential brood rearing cover providing food and shelter for chicks. 71 5.2 Number of field trials in different farmland habitats over 2007, 2008 and 2009. 72 5.3 Data used to assess vegetation structure. 74 5.4 Comparing the proportions of different taxa collected in sweep net and vacuum samples. 75 5.5 Comparing the proportions of different taxa found in the diet of pheasant chicks with those collected in sweep net samples. 77 5.6 Comparing the proportions of different taxa found in the diet of pheasant chicks with those collected in vacuum samples. 77 5.7 Ranking matrices of the relative differences in the larval component of the diet of pheasant chicks foraging in different cereals. 81 5.8 Ranking matrix of the relative differences between the diets of human- imprinted pheasant chicks foraging in crop and non-crop areas. 86 5.9 Compositional analysis results comparing the larval component of the diet of pheasant chicks foraging in crop and non-crop areas. 86 5.10 Ranking matrix of the relative differences in the Hemiptera component of the diet of pheasant chicks foraging in crop and non-crop areas. 88 5.11 Ranking matrix of the relative differences in the Hymenoptera component of the diet of pheasant chicks foraging in crop and non- crop areas. 88 5. 12 Ranking matrix of the relative differences between the diets of pheasant chicks foraging in long-term set-aside and game crop areas. 94 5.13 Ranking matrix of the relative differences in the Hemiptera component of the diet of pheasant chicks foraging in game crop and long-term set- aside areas. 95 5.14 Ranking matrix of the relative differences in the Hymenoptera component of the diet of pheasant chicks foraging in game crop and long-term set-aside areas. 96 6.1 GLM results showing variables affecting the number of chicks visible during field trials. 112 6.2 GLM results showing variables affecting the distance of foraging chicks from their human handler. 113

7 7.1 Behaviour observed by breeding skylarks. 125 7.2 GLM results showing how crop type influences territory density. 128 7.3 GLM results showing variables affecting skylark territory density. 129 7.4 Ranking matrix of the relative differences between the diets of wild skylark chicks and human-imprinted pheasant chicks foraging in long term set-aside and game crop areas. 134 7.5 Ranking matrix of the relative differences between the diets of wild lapwing chicks and human-imprinted pheasant chicks foraging in long term set-aside and game crop areas. 135 7.6 Ranking matrix of the relative differences within the Hemiptera between the diets of human-imprinted pheasant chicks and wild lapwing chicks. 136 7.7 Ranking matrix of the relative differences between the diets of wild lapwing and skylark chicks. 136 7.8 Ranking matrix of the relative differences within the Hemiptera between the diets of wild lapwing and skylark chicks. 137

List of figures

2.1 Topographical map of Austria showing the location of the Seefeld estate. 27 2.2 Rainfall and average temperature during May and June at the Seefeld estate 29 2.3 Bag records for pheasant, hare, duck, fox and others on the Seefeld estate over the past 50 years. 30 2.4 Winter wheat yields as a proxy for agricultural intensificationat the Seefeld estate over the past 50 years. 31 2.5 Field plan of the Seefeld estate. 32 2.6 Example of an area of long-term set-aside on the Seefeld estate. 33 2.7 Imprinting and brooding the chicks during the first day. 35 2.8 Measuring the visual obstruction score of a chick sized tennis ball. 41 3.1 Variation in the number of insects eaten by chicks of different ages 47 3.2 Cumulative proportion of fragments returned over 24 hours from the faeces of hand-reared pheasant chicks (a) Diptera fragments, (b) Trilobium fragments, (c) Dermestes fragments (d) Tenebrio 48- fragments, (e) Ephestia fragments, (f) Formicidae fragments. 49 3.3 Proportion of insect fragments returned when offered high quantity and low quantity diets. 50 3.4 Comparison of correction factors (f) calculated for the pheasant and bobwhite quail. 52 4.1 The quantity and taxonomic diversity of invertebrate groups eaten by farmed and wild strain imprinted pheasant chicks. 59 4.2 The dietary composition of invertebrate groups eaten by farmed and wild strain imprinted pheasant chicks. 60 4.3 The dietary composition of invertebrate groups eaten imprinted (2007-2008) and wild (2001-2002) pheasant chicks. 61 4.4 The quantity and taxonomic diversity of invertebrate groups eaten by imprinted (2007-2008) and wild (2001-2002) pheasant chicks. 62

8 4.5 Average distance between chicks and handler over the 30 minute field trial for farmed and wild strain imprinted pheasant chicks. 63 4.6 Average distance between imprinted pheasant chicks and handler over the 30 minute field trial at different ages. 64 5.1 The number of invertebrates collected by different sampling methods. 75 5.2 Comparing proportions of invertebrate orders found in the field by vacuum sampling and sweep netting with the proportions found in the diet of pheasant chicks. 76 5.3 Comparing proportions of invertebrate families and larvae found in the field by vacuum sampling and sweep netting with the proportions found in the diet of pheasant chicks. 77 5.4 Total number of invertebrates found in different crop types using two different sampling methods. 78 5.5 The quantity and taxonomic diversity of invertebrate groups eaten by human-imprinted pheasant chicks foraging in crop fields. 79 5.6 Dietary composition of human -imprinted pheasant chicks foraging in crop fields. 79 5.7 Proportions of larvae types eaten by pheasant chicks foraging in different crop fields. 80 5.8 The interaction between year and crop type on the proportion of different larval groups consumed by pheasant chicks foraging in spring and winter sown cereals and in non-cereal (other) crops. 82 5.9 Vegetation structure of commercial crops 83 5.10 Visual obstruction scores when viewing a chick sized object in different commercial crops. 83 5.11 Total number of invertebrates found in cropped and non -cropped areas using two different sampling methods. 84 5.12 The quantity and taxonomic diversity of invertebrate groups eaten by human-imprinted pheasant chicks foraging in crop and non-crop areas. 85 5.13 Dietary composition of human-imprinted pheasant chicks foraging in crop and non-crop areas. 85 5.14 Composition of Hemiptera in the diet of pheasant chicks foraging in crop and non-crop areas. 87 5.15 Composition of Hymenoptera in the diet of pheasant chicks foraging in crop and non-crop areas. 88 5.16 Composition of Hymenoptera in the diet of pheasant chicks foraging in crop and non-crop areas, split by year. 89 5.17 Vegetation structure of commercial crops and non-crop areas. 90 5.18 Visual obstruction scores when viewing a chick sized object in commercial crops and non-crop areas. 90 5.19 CCA biplot of habitats by chick diet. 92 5.20 Total number of invertebrates found in long term set-aside and game crop areas using two different sampling methods. 93 5.21 The quantity and taxonomic diversity of invertebrate groups eaten by human-imprinted pheasant chicks foraging in long-term set-aside and sown game crops. 93 5.22 Dietary composition of human -imprinted pheasant chicks foraging in game crop and long-term grassy set-aside. 94

9 5.23 Composition of Hemiptera in the diet of pheasant chicks foraging in game crop and long-term set-aside areas. 95 5.24 Composition of Hymenoptera in the diet of pheasant chicks foraging in game crop and long-term set-aside areas. 96 5.25 Vegetation structure of sown game crop and long-term grassy set- aside. 97 5.26 Visual obstruction scores when viewing a chick sized object in different set-aside habitats. 97 5.27 CCA biplot of non -crop habitats by chick diet. 98 6.1 The quantity and taxonomic diversity of invertebrate groups eaten by pheasant and grey partridge chicks. 110 6.2 The dietary composition of invertebrate groups eaten by pheasant and grey partridge chicks foraging together. 110 6.3 Comparing proportions of invertebrate orders found in the field by vacuum sampling and sweep netting with the proportions found in the diet of grey partridge chicks. 111 6.4 The interaction between chick age and species on the number of chicks visible over the field trials. 112 6.5 The average number of chicks visible d uring field trials in different habitat types. 112 6.6 Average distance between chicks and their human hander 113 7.1 Population trends in UK bird species compared with 1970 population levels, split by habitat type. 117 7.2 Territory densities on different crop types. 129 7.3 Relationship between skylark territory density and (a) vegetation structure, (b) boundary index. 130 7.4 Comparing proportions of invertebrate orders found in the field by vacuum sampling and sweep netting with the proportions found in the diet of lapwing chicks. 132 7.5 Comparing proportions of invertebrate orders found in the field by vacuum sampling and sweep netting with the proportions found in the diet of skylark chicks. 133 7.6 Comparing proportions of invertebrate orders found in the field by vacuum sampling and sweep netting with the proportions found in the diet of yellow wagtail chicks. 133 7.7 The quantity and taxonomic diversity of invertebrate groups eaten by human-imprinted pheasant chicks and wild skylark, yellow wagtail and lapwing chicks. 133 7.8 Comparison of the dietary composition of human -imprinted pheasant chicks with wild lapwing, skylark and yellow wagtail chicks foraging on arable farmland. 134 7.9 Composition of Hemiptera in the diets of human-imprinted pheasant chicks and wild lapwing chicks foraging on arable farmland. 136 7.10 Composition of Hymenoptera in the diets of wild lapwing and skylark chicks foraging on arable farmland. 137 7.11 CCA biplot of species including grey partridge. 13 8

10 1 INTRODUCTION AND BACKGROUND INFORMATION

1.1 Introduction

The common pheasant (Phasianus colchicus ) is an important gamebird across Europe and is the most common gamebird found on agricultural land. Over the twentieth century the intensification of agriculture has put more pressure on these man-made habitats and many farmland bird populations have declined (Chamberlain et al. 2000; Donald et al. 2001b; Gregory et al. 2004; Donald et al. 2006). Changes in the timing of cultivation, crop types sown and field size have deteriorated habitats and increased disturbance in a variety of ways which will be discussed in detail below. The increased use of pesticides on these intensive fields has led to a decline in invertebrate prey available for foraging birds (Southwood and Cross 1969; Wilson et al. 1999; Boatman et al. 2004; Holland et al. 2006; Taylor et al. 2006). Invertebrates are a key dietary requirement for the chicks of many farmland birds, including the pheasant and other gamebirds (Galliformes) (Savory 1989; Palmer et al. 2001; Holland et al. 2006), passerines (Passeriformes) (Newton 2004; Winspear and Davies 2005; Holland et al. 2006) and waders (Charadriiformes) (Kimmel and Healy 1987; Winspear and Davies 2005; Holland et al. 2006; Butler 2007). To reverse the decline in farmland biodiversity it is essential to find ways of modifying farming practices to support farmland birds, mammals and the seeds and invertebrates they feed on. This study investigates the foraging of pheasant chicks on different arable habitats during the breeding season and relates this to other gamebirds and farmland birds.

Measuring the suitability of habitats for foraging birds has always been a difficult issue (Cooper and Whitmore 1990; Hutto 1990; Wolda 1990). Conventional methods of measuring invertebrate abundance such as sweep-netting and vacuum sampling are often used to assess invertebrate abundance in different habitats (Leather 2005). Relative measures are easy to execute but are biased towards sampling only a part of the invertebrate fauna present; sweep-netting for example tends to favour the top of crops but misses out on ground-dwelling invertebrates. Absolute measures which capture the whole invertebrate community are more time consuming and are not always more biologically relevant. Conventional methods do not take into account the varying accessibility of different potential prey items to the birds (Cooper and

11 Whitmore 1990; Hutto 1990) or selective preference by the birds for one prey type over another (Hill 1985; Palmer et al. 2001; Moreby et al. 2006). It is possible to correct for this by scaling absolute counts using factors calculated by previous studies. One such method is the Chick Food Index developed by the Game and Wildlife Conservation Trust based on faecal analysis of grey partridges (Perdix perdix ) (Potts and Aebischer 1991). Another method is to use the birds themselves to assess arthropod availability in different habitats. By careful analysis of the arthropod fragments in bird faeces it is possible to identify what the bird has been eating (Green 1984; Hill 1985; Moreby 1988; Rosenberg and Cooper 1990)

Many studies have looked at avian diet by collecting samples from wild birds by dissecting the gut (Ford et al. 1938; Palmer et al. 2001; Smith and Burger 2005), the use of neck collars to collect crop samples (Orians 1966; Wilson 1966; Dyrcz and Flinks 2003), flushing the digestive tract with a saline solution or emetic (Moody 1970; Jenni et al. 1990; Gionfriddo et al. 1995; Hess 1997) or collecting faeces (Bryant 1973; Davies 1976; Davies 1977; Ralph et al. 1985; Pyke 1989; Smith and Burger 2005). Whilst these have provided an important source of information on general diet, wild birds often feed in several different habitats, so the merits of each cannot be considered separately, even when the feeding sites are known. To circumvent this issue birds can be raised in captivity and allowed to forage in specific habitat types before their droppings are collected. The raised birds are often imprinted onto a surrogate ‘mother’ figure - either a broody hen or a human researcher (Kimmel and Healy 1987). Imprinting onto a broody hen provides natural brooding conditions and perhaps more natural foraging behaviour. Imprinting onto a researcher has the advantage of being able to gather up the birds to collect their droppings without causing undue stress (Pyke 1989). Studies in the United States of America (USA) have used human-imprinted northern bobwhite quail (Colinus virginianus ) (Palmer et al. 2001; Smith and Burger 2005; Butler 2007) and greater sage-grouse (Centrocercus urophasianus ) (Huwer 2004) chicks to assess aspects of foraging, and researchers in Germany have carried out similar studies using grey partridge chicks ( Perdix perdix ) (Herrmann and Fuchs 2006).

The pheasant is a suitable candidate for such work as it has a long history of being successfully raised in captivity by humans (Edminster 1954; Robertson 1997). Wild

12 chicks start foraging soon after they are hatched (Starck and Ricklefs 1998) and the behaviour is thought to be innate since the hen neither feeds the chicks nor shows food to them (Robertson 1997). Rare cases of a hen indicating an item of prey to her chicks have been observed but these appear to be the exception rather than the rule (Robertson 1997). No information can be found on the use of human-imprinted pheasant chicks besides a few brief mentions implying it can be done (Kimmel 1985; Kimmel and Healy 1987; Regenscheid et al. 1987; Jalme et al. 2003).

1.1 Farmland as a natural resource

The total area of agricultural land has increased globally by 466% over the last three centuries, making it one of the most significant human alterations to the planet (Matson et al. 1997). Whilst the increase in land area under agriculture has slowed over the past century, yields have continued to increase (O'Connor and Shrubb 1986; Matson et al. 1997). Globally only 10.6% of the total land area is used for arable farming (CIA 2009), since much of the Earth’s surface has unsuitable growing conditions, being too hot, too cold, too mountainous or with unfavourable soil conditions. In the UK alone 18.7 million hectares (77% of the total land area) is agricultural land, including 41% grassland and 25% rough grazing. Cropped arable land covers 4.7 million hectares, the majority of which (69%) consists of cereal crops (DEFRA 2009a). With such a large proportion of non-urban areas being farmed for crops or livestock little truly natural habitat is available. Farmland has therefore become an important potential source of biodiversity, particularly in countries with a high population density.

Europe, being a temperate region, has favourable growing conditions allowing 25.5% of its land area to be farmed as arable (IBRD 2009). This amount varies between countries depending on their economic history, climate and terrain; much of Austria is mountainous (Schneider 2003) leaving only 16.8% arable land compared to 23.7% of the UK (IBRD 2009). Industrialisation in Austria only began on a large scale after the second World War (Schneider 2003) and the majority of Austrian farms are still small (averaging 14 ha) family-run subsistence farms (Quendler 2005) with strip farming commonly occuring. Strip farming increases habitat heterogeneity during the spring and early summer since several crop types are grown in a single field

13

Farming is not a new activity; people have been farming in Europe for over 6000 years (Boag and Tapper 1992). Early farming methods left many niches which plants and small animals have adapted to utilise. Hedgerows provide shelter for many plants and animals (Lewis 1969; Parish et al. 1994; Corbit et al. 1999; Thomas et al. 2001) and provide corridors linking different habitats (Forman and Baudry 1984). Crop rotation provides a heterogeneous environment with cover and food available throughout the year, allowing farmland to become a refuge for native flora and fauna as their natural habitat slowly contracts. Until the advance of mechanisation farming methods altered slowly, allowing many plants and animals to adapt and evolve to suit this expanding habitat. The result is that many species have come to rely on farmland as their primary or sole habitat.

1.1.1 Detrimental effects of the intensification of agriculture

In the past 150 years farming has changed dramatically, with a huge increase in mechanisation and specialisation (O'Connor and Shrubb 1986; Boag and Tapper 1992; Stoate et al. 2001). This has led to a severe decline in biodiversity and populations of farmland birds across the whole of Europe (Chamberlain et al. 2000; Donald et al. 2001b; Donald et al. 2006; Wretenberg et al. 2006). The changes associated with the increased intensification of farming have affected different taxa in different, and often interacting, ways (Siriwardena et al. 1998; Gregory et al. 2004; Newton 2004; Winspear and Davies 2005; Ahnström et al. 2008; Firbank et al. 2008). The major changes and their effect on bird populations are discussed below, but it is important to remember that these changes not only affect the avifauna but all plants and animals that utilise farmland habitats (Boag and Tapper 1992; Wilson et al. 1999; Stoate et al. 2001).

The number of tractors and associated machinery has increased dramatically on farmland since the 1940s (O'Connor and Shrubb 1986). Modern heavy machines create more disturbance of the soil and farmland than the slower traditional methods did (Newton 2004). This can prove fatal to the eggs and chicks of ground-nesting birds such as the lapwing (Vanellus vanellus ), skylark (Alauda arvensis ) and yellow wagtail (Motacilla flava ) (Johansson and Blomqvist 1996; Eaton and Bradbury 2003;

14 Newton 2004). With increased mechanisation comes the need for larger fields and the removal of many ancient hedgerows. These field boundaries provided essential habitats for nesting, roosting and foraging farmland birds. The grey partridge prefers to nest in grassy field margins (Blank et al. 1967; Panek 1997) whereas many passerines such as the yellowhammer (Emberiza citrinella ) and tree sparrow (Passer montanus ) nest within hedgerows (Stoate et al. 1998; Field and Anderson 2004; Whittingham et al. 2005). Hedges also provide important refugia and corridors for other wildlife, such as small mammals, invertebrates and plants (Lewis 1969; Forman and Baudry 1984; Micol et al. 1994; Walsh and Harris 1996; Verboom and Huitema 1997; Corbit et al. 1999; Thomas et al. 2001).

The increased use of agri-chemicals (Chamberlain et al. 2000; Ewald and Aebischer 2000) coupled with advances in crop genetics has allowed farmers to break away from the traditional rotation of agricultural land and to grow high yield crops continuously. The area of winter crops, especially wheat, and oilseed rape has increased greatly since the early 1980s, while the area of other cereals and many root crops has declined (Chamberlain et al. 2000). This increased specialisation has led to large fields dominated by a single crop species. Such homogenisation of the landscape is detrimental to biodiversity as it decreases the number of ecological niches available (Fuller et al. 1995; Matson et al. 1997; Henderson et al. 2009).

These monocultures require a continual high input of inorganic fertilisers and pesticides. The early synthetic pesticides such as DDT accumulated in the environment and had direct effects on non-target species, especially higher predators such as the peregrine and sparrowhawk (Ratcliffe 1970; Fry 1995). Even when pesticides have no direct effect on survival (Somers et al. 1972), insecticides and herbicides can have indirect effects via the food web. Herbicide use decreases available seed supplies for seed-eaters such as the yellowhammer, reed bunting (Emberiza schoeniclus ) and tree sparrow (Newton 2004). Insecticides and herbicides both decrease the invertebrate prey available; the latter indirectly by affecting the weed community (Rands 1985; Marshall et al. 2003; Taylor et al. 2006). This decline in available prey has affected the grey partridge, pheasant, yellowhammer, corn bunting (Miliaria calandra ) and many other farmland birds, which rely heavily on invertebrates during the breeding season (Southwood and Cross 1969; Warner et al.

15 1984; Rands 1985; Siriwardena et al. 1998; Wilson et al. 1999; Boatman et al. 2004; Holland et al. 2006; Kuijper et al. 2009).

The change from spring-sown to winter-sown crops began in the late 1960s (O'Connor and Shrubb 1986; Chamberlain et al. 2000) and has affected bird populations at two crucial times of year. Firstly, it removes over-winter stubble, which provides an important foraging habitat for many farmland birds (Fuller et al. 1995; Matson et al. 1997; Newton 2004; Gillings et al. 2005; Wilson et al. 2005; Winspear and Davies 2005; Henderson et al. 2009). Secondly, winter-sown cereals germinate earlier and create a taller, denser habitat during the breeding season. Many ground- foraging birds such as the skylark, yellowhammer and yellow wagtail prefer short vegetation with sparse growth or bare patches, making it easier to find prey (Poulsen et al. 1998; Toepfer and Stubbe 2001; Atkinson et al. 2004; Newton 2004; Whittingham and Evans 2004). Crop structure is also important in determining predation risk and birds that fly away from danger prefer shorter vegetation as it gives them a better view of approaching danger (Atkinson et al. 2004; Whittingham and Evans 2004; Wilson et al. 2005). The earlier harvesting of winter-sown cereals also disturbs breeding birds and can destroy both eggs and chicks (Winspear and Davies 2005).

Grasslands have not been immune to intensification; areas of rough grazing and hay production have declined with the increase in silage production and improved grasslands, both requiring high fertiliser inputs (Chamberlain et al. 2000). Silage is cut earlier in the year than hay causing disturbance to ground-nesting birds such as the corncrake (Crex crex ) (Cadbury 1980). Drainage of wet meadows has also occurred on a large scale, removing habitats essential to many wader species such as the lapwing and common snipe (Gallinago gallinago ) (Green 1988; Green et al. 1990; Johansson and Blomqvist 1996; Wilson et al. 2004; Winspear and Davies 2005).

1.1.2 Can agri-environment schemes benefit farmland birds?

In the 1960s the Common Agricultural Policy (CAP) came into effect to maintain strong state intervention in agriculture, which required the standardising of policies across the European Community. The CAP introduced set-aside payments in 1988 as

16 a measure to halt the wasteful and costly overproduction of produce such as grain and milk. Farmers were paid a subsidy above the cost of their crop to keep some land out of production. Set-aside became compulsory in 1992 at 15% of the farmed area but was reduced to 10% in 1996. The CAP reform in 1992 also brought in Regulation 2078/92, providing EU funding for nationally implemented schemes encouraging environmentally friendly production (Buller et al. 2000). In 1999 the EU introduced Agenda 2000 which gives greater opportunities to make direct payments for environmentally friendly farming (Anon 1999; Buller et al. 2000). Some of the procedures highlighted under Regulation 2078 include: • Reduce use of fertilsers and/or plant protection products (or keep previous reductions and introduce/continue organic farming) • Establish or maintain non-intensive production methods and grasslands • Reduce livestock stocking density • Use farming methods that protect the environment, natural resources and landscape • Rear local breeds in danger of extinction • Upkeep of abandoned farmland and woodland • Set-aside farmland for at least 20 years, especially the establishment of biotope reserves, national parks and protected hydrological systems. • Aid for training farmers in environmentally friendly management.

Countries within the EU have implemented different agri-environment schemes (AES) to varying degrees of success (Buller et al. 2000), such as the Single Payment Scheme (SPS). The SPS is the principle agricultural subsidy scheme within the EU and links subsidies to environmentally friendly farming practices (DEFRA 2009b). Due to the increase in crop value, compulsory set-aside was reduced to 0% in 2007 and financial support for these schemes was discontinued in 2008 (Europa 2007). The potential loss of these non-cropped areas may have a significant detrimental effect on farmland biodiversity, increasing the need for effective AES (Kubišta 1990; Corbet 1995; Vickery et al. 2004; Kaiser et al. 2006; MacDonald et al. 2007).

In the UK Environmentally Sensitive Areas (ESA) and the Countryside Stewardship Scheme (CSS) have been replaced by the Environmental Stewardship Scheme, which

17 allows farmers to claim funding for various AES implemented on their farms (Anon 2009). The Environmental Stewardship is a tiered scheme with Entry Level Stewardship (ELS) being available to all farmers. Other options include Organic Entry Level Stewardship (OELS) for organic farms and Higher Level Stewardship which combines with either ELS or OELS and targets key features (Anon 2009). Options available under ELS include aspects of hedgerow and ditch management, buffer strips, field margins that are naturally regenerated or sown with specified seed mixtures, overwinter stubble, beetle banks and undrilled skylark plots (Anon 2008).

Field margin options are one of the most common AES, due to the fact that many different options are available and they do not involve changes within the field. They may affect the management of existing structures such as hedgerows or ditches or require a corner or strip of field to be taken out of normal cultivation (Anon 2008). The wild bird seed mix and nectar flower mix are two options to sow on margins designed to encourage farmland birds and pollinators respectively. Options vary between schemes and countries and can include other seed mixes or naturally regenerated strips. Naturally regenerated and grass/wildflower mixes can provide greater potential invertebrate and seed food over the summer for birds (Kromp and Steinberger 1992; Vickery et al. 2002; Marshall et al. 2006). Mixes including both grass and wildflower seeds appear to be of greatest benefit to most invertebrates (Meek et al. 2002; Woodcock et al. 2008) although bees and butterflies require suitable nectar plants in the mix (Carvell et al. 2007). Conservation headlands are possibly the easiest margin option to implement as the crop is planted as usual but with an outer strip of crop (usually 6m) being selectively sprayed avoiding insecticides and broad-leaved pesticides. This strip helps to buffer the field margin and encourages additional plants and insects into the field (Hassall et al. 1992; Kleijn and van der Voort 1997; Moreby and Southway 1999). The increased diversity of potential food is beneficial to farmland birds such as the grey partridge (Potts 1986; Sotherton and Robertson 1990; Chiverton 1999) and also to small mammals (Tew et al. 1992a).

Agri-environment schemes have been shown to be beneficial to plants, invertebrates and mammals (Tew et al. 1992b; Kleijn and van der Voort 1997; Meek et al. 2002; Vickery et al. 2002; Klein et al. 2006; MacDonald et al. 2007; Smith et al. 2008a;

18 Smith et al. 2008b; Woodcock et al. 2008) but their effects on bird populations have been less successful (Klein et al. 2006; Marshall et al. 2006; Cole et al. 2007). Schemes acting on field margins will only influence a small proportion of the habitat used by the birds, to be effective AES must target the crop itself and be specific to the requirements of the birds (Klein and Sutherland 2003; Butler et al. 2007). For example, higher tier ESAs which enhanced the environment instead of just maintaining it have helped increase wader populations (Ausden and Hirons 2002; Wilson et al. 2007). Another example of a targeted AES available under the ELS scheme is the provision of skylark patches within the crop field. Skylark plots are undrilled sections of a minimum of 16 m 2 set away from hedgerows, trees or tramlines (Anon 2008). These do not enhance invertebrate abundance or diversity, nor do they provide nesting habitats (Morris et al. 2004; Smith et al. 2009), but do increase skylark chick survival by providing better foraging habitats (Morris et al. 2004; Clarke et al. 2007).

Organic farming is another AES existing in several countries and due to its low input system it too can benefit farmland birds such as the skylark (Wilson et al. 1997; Chamberlain et al. 1999b; Bartram and Perkins 2003; Henderson et al. 2009). The farming techniques used encourage invertebrate prey populations by the avoidance of pesticide use (Kromp 1989; Reddersen 1997; Pfiffner and Luke 2003; Bourassa et al. 2008). Due to the avoidance of inorganic fertilisers, organic crops grow more slowly and provider the sparser, shorter foraging habitat preferred by the skylark (Wilson et al. 1997). Organic farming also increases the abundance and/or biodiversity of invertebrates, plants and mammals (Kromp 1989; Bartram and Perkins 2003; Pfiffner and Luke 2003; Gabriel and Tscharntke 2007; MacDonald et al. 2007; Bourassa et al. 2008).

Austrians recognised the responsibility for farmland ecology during the 1980s and began implementing nation agri-environment programmes (AEPs) even before they joined the EU in 1995. Austria helps lead the way in ecological farming with agri- environment subsidies being paid to the majority of farms (71%) (Schmitzberger et al. 2005) and 10% of its total arable area is given over to organic farming (Molterer 1999). These AEPs have been shown to be beneficial to farmland plants, insects and birds and also beneficial at a landscape level (Kromp 1989; Kromp 1990; Klein and

19 Sutherland 2003; Wrbka et al. 2008). Austria is one of only two European countries where farmland bird populations are actually showing a positive trend (Donald et al. 2006). Large scale conservation laws in Austria allow landscape level programmes to be implemented but unfortunately these suffer from problems of communication between workers at each level (Panek 2002).

1.2 Natural history of the pheasant (Phasianus colchicus )

1.2.1 Taxonomy and distribution

The common pheasant (Phasianus colchicus ) (Galliforme: Phasanidae), is a bird well- known in western Europe. Loved by huntsmen, it has been voted the most hated bird in Britain by ornithologists who had it declared an honorary mammal (Robertson 1997). The order Galliformes contains all land based gamebirds, with ducks and other waterfowl in the sister order Anseriformes. Pheasants, together with chickens, grouse, partridges and Old World quail, make up the family Phasanidae.

The natural range of P. colchicus is from the eastern shore of the Black Sea to the Caspian sea and it extends eastwards towards the south-east corner of Asia (Edminster 1954; Hill and Robertson 1988). The distribution is not continuous; rather it occurs in a few distinct blocks, each of which contains several of the 30 subspecies of P. colchicus . The Japanese green pheasant, P. versicolor , is native to Japan and has been split into two subspecies. It is likely this species have been overly split as often happens when an animal is so closely studied by many people (Robertson 1997).

Man has greatly increased the pheasant’s distribution to the extent that it is one of the most widely introduced bird species (Hill and Robertson 1988). According to mythology the introduction to Europe began in 1300 BC when the Argo returned to Greece bringing with it pheasants from the Colchis region of the Caucasus. Certainly the Romans kept them as table birds as proven by surviving records on husbandry and recipes and probably extended the pheasant’s range through southern Europe (Robertson 1997). It is possible they also introduced the pheasant to Austria as the pheasant was well establish through mainland Europe prior to its introduction to Britain (Robertson 1997). Whilst obscure references to what may be a pheasant are

20 found as early as the twelfth century it is unlikely the pheasant became commonplace in Britain before the fourteenth century (Yapp 1983). The Normans are commonly held responsible for establishing the pheasant in Britain and reports of pheasant breeding in the wild in Britain are found by the fifteenth century (Hill and Robertson 1988; Robertson 1997). By the end of the seventeenth century it had increased its range to include Scotland, Wales and Ireland. Phasianus colchicus colchicus was the first to be introduced; later P. versicolor and other subspecies of P. colchicus were also introduced. These have interbred leaving the British population with varying characters from each race (Hill and Robertson 1988). Hereafter ‘pheasant’ refers to all of the introduced, and probably interbred, populations of the common pheasant found throughout Europe.

During the nineteenth and twentieth centuries the range of the pheasant in Europe continued to increase spreading north to include Norway, Finland and Sweden. Attempts to introduce pheasants to Russia and eastern Europe have mostly failed with the exceptions of northern Transcaucasia and a reintroduction to the northern Caucasus (Hill and Robertson 1988). Many attempts were also made to introduce the pheasant to North America during the eighteenth and nineteenth centuries, at last succeeding in the early 1880s in Willamette Valley, Oregon (Edminster 1954; Hill and Robertson 1988). After this uninspiring start several more successful introductions were made and the pheasant population has quickly spread. By the 1990s the pheasant had colonised over 35 states, nine Canadian provinces and a small part of Mexico (Robertson 1997). The best pheasant ranges in the USA remain in the northern regions and the pheasant is an established and important gamebird (Edminster 1954). Similar attempts to introduce the bird to mainland Australia during the nineteenth and twentieth centuries have all failed although the pheasant has been successfully released in New Zealand and on several smaller islands (Hill and Robertson 1988).

Whilst the pheasant received much attention in its introduced range relatively little has been known in the West about its native range. With improving relations between the East and West at the end of the twentieth century this can begin to be rectified. China contains more species of pheasant than any other country, including the common pheasant. It was once thought that the common pheasant was native to

21 marshlands but at the Pangquangquo reserve in the Shanxi Province the common pheasant is found primarily in shrubs, along forest edges and on farmland; only seldom is it found in marshlands (Robertson 1997). The pheasant is, however, very adaptable and thrives in many diverse habitats from fertile farmland and scrub to exposed coasts and islands, from the wide open American Midwest prairies to 3000 m high Chinese mountain tops (Robertson 1997; Wang et al. 2004). In its native range the pheasant is found at various altitudes but usually associated with meadows or grasslands and broad-leaved forests (Wang et al. 2004; Ai 2006). This supports the hypothesis that vegetation structure is the driving force determining pheasant distribution.

1.2.2 Ecology and habitat use

The pheasant’s behaviour during late autumn and winter was the first period to be well documented, as this includes the hunting season. As the weather gets colder birds come together to form flocks in good over-wintering habitats (Edminster 1954). In Britain there is a long history of planting woodlands specifically for pheasants to use over winter, with literature dating back over 100 years (Robertson 1997). Pheasants use woodland edges and are usually found no more than 30 metres into the wood. Consequently small woods, particularly ones which are long and thin, have the highest pheasant densities. In larger woods, wide woodland rides can successfully mimic the habitat found at the edge and be ideal for pheasants (Robertson 1997). Rather than favouring certain plant species the spatial structure of the woodland is important. Dense shrub cover up to six metres high is required to provide cover from predators and protection from the weather, but should not be too dense at ground height to allow easy movement (Robertson 1997). Young conifers, coppiced woodland and rhododendron all provide good cover, whilst open beech woods are less suitable. This is similar to the rhododendron and broad-leabed forests where they are found in their natural range (Wang et al. 2004; Ai 2006). The birds also spend a significant amount of time in crops such as kale and maize (Robertson 1997), as well as areas of wetland (Anderson 2002). The better the quality of winter habitat the healthier the hens in spring, leading to a more successful breeding season (Anderson 2002).

22 In March and April birds disperse from the woodlands and the cocks set up territories where they display to the hens. These territories are along boundaries with an open area for feeding adjacent to an area of dense cover. Unusually for birds, pheasants form polygynous harems with several females for each territorial male. The cock guards the females from interruption from other cocks and predators whilst they feed, although a hen may also visit the territories of other cocks. Hens remain with the cock for four to six weeks before leaving to build a nest away from the cock’s territory. The pheasant’s nest is a simple scrape in the ground which the hen will visit once or twice daily to lay her eggs. Once all her eggs are laid, usually totalling around 11, she will start incubating (Robertson 1997). If she loses her first batch of eggs she will lay a second, and even a third or fourth if she starts early enough. Most eggs lost are due to predation, either from corvids pre-incubation or mammalian predators once incubation has started. In agricultural fields disturbance can also cause significant losses (Edminster 1954; Robertson 1997). In Europe only one brood is ever successfully raised by the hen each year but in New Zealand the longer summer has occasionally allowed two broods to be raised (Robertson 1997). Hens prefer to nest in areas of set-aside and wetlands, but with much of their home ranges being given over to agriculture large numbers utilise crop fields (Edminster 1954; Robertson 1997; Anderson 2002; Bliss 2004); interestingly nesting success appears to be much lower in wetlands than in either set-aside or commercial crops (Bliss 2004) and it may be that there is increased predator activity near water. In their native range phesants prefer to nest in more covered areas and in larger tussocks to provide better shelter and concelment from predators, and they too favour sites nearer to water (Long et al. 2007).

Chicks hatch after 25 days incubation, with around four fifths hatching successfully (Robertson 1991; Robertson 1997; Bliss 2004). Pheasant chicks are precocial (Starck and Ricklefs 1998), they hatch with a covering of downy feathers and are able to walk and forage as soon as they have dried. The hen takes her chicks to forage in crop fields, set-aside areas and other patches of weedy grassland (Hill 1985; Draycott et al. 2002; Bliss 2004). Home ranges that include wetland areas show a higher chick survival rate (Bliss 2004) , possibly due to the cover they provide from predators and agricultural disturbance or an increased abundance of invertebrates near water. Again it is the vegetation structure that is most important in determining an area of good

23 chick foraging and woodlands tend to be avoided at this time of year (Bliss 2004). During their first couple of weeks chicks require an abundance of insects in their diet to supply sufficient protein for growth and essential amino acids for feather development (Savory 1989; Dahlgren 1990). Their foraging habitat should therefore provide plenty of slow moving invertebrates at ground level. Chicks are unable to thermoregulate during most of this time (Offerdahl and Fivizzani 1987) and require brooding from their mother during unfavourable weather conditions. If vegetation is too dense at ground level it can become saturated with water, soaking the chicks and often leading to death by hypothermia. Pheasant chicks are vulnerable to predation and mammalian predators are the principal cause of brood loss (Hill 1985; Bliss et al. 2006), therefore sufficient vegetation cover is required to protect the chicks from predators.

1.2.3 Why are pheasants important?

Historically cycles of depression and boom in the agricultural sector have brought much land in and out of agricultural use since the mid-nineteenth century (Boag and Tapper 1992). One such severe recession hit British farming in the late 1800s and as land was taken out of agricultural use an alternative purpose was found for it by a new cohort of the rich created by the industrial revolution who desired a country estate and the associated sporting lifestyle. This led to the creation of many country shooting estates and habitat management for game has altered very little since then, being mainly focused on winter habitat since most released birds will have been shot by spring (Robertson 1997). Today almost four fifths of birds shot for sport in the UK are pheasants and the vast majority of these are reared and released (PACEC 2006). With the advent of the First World War agriculture increased in Britain and manpower was required in the armed forces leading to a decline of shooting estates. The interwar peace brought another severe recession as imports recommenced and whilst farm employment declined gamekeepers were again in demand, although never reaching pre-war numbers (Boag and Tapper 1992). The Second World War had similar effects to the first, however the Government kept another recession at bay with a series of support programmes.

24 Currently the management of two-thirds of the rural land in the UK is influenced by shooting and two million hectares of this is managed specifically for shooting (PACEC 2006). Shooting organisers undertake much work that complements management done by conservation organisations thereby providing a public service at personal expense. This includes the creation and maintenance of woodlands, hedgerows, wetlands, beetle banks and conservation headlands and the carrying out of pest control. Arable land that is used for gamebird shooting tends to include areas of game crop such as sorghum or kale to provide over-winter food and cover. Natural grassland and sown seeds such as millet, sorghum, lucerne and wildflower mixes are also good game crops (Kubišta 1990; Maidens and Carroll 2002; Draycott et al. 2009) and these can also be used by other farmland bird species (Sage et al. 2005). The majority of this management relies on the shooting industry and would cease or alter drastically if shooting stopped (PACEC 2006). Despite being Britain’s most hated bird it seems the pheasant plays a crucial role in the management and conservation of habitats that benefit a host of other species.

1.3 Study aims

The principal aim of this study was to evaluate the foraging potential of different arable habitats for pheasant chicks. Human-imprinted pheasant chicks were used as a sampling tool to gain information about what invertebrates were consumed in the various habitats. The first aim of the project was to sucessfully develop a methodology to imprint the chicks and use them in field trials. The main hypothesis of the study was that non-cropped areas of farmland will provide better foraging in terms of the number of invertebrates available and in the types of invertebrates available. Different types of non-cropped habitat were compared to determine which management prescriptions are best for pheasant broods.

In order to validate the methods used the diets of wild and farmed pheasant chicks were compared with the hypothesis that no difference would be found in their diets. Chicks from wild gathered eggs were imprinted and compared to those bought from a game farm. Dietary data from previous studies at the field site were also included in the analysis. To remove any bias from using faecal samples factors were calculated

25 based on laboratory feeding experiments to correct for any differences in digestion rates for different invertebrate fragments.

Further hypotheses were postulated that other bird species would benefit from land managed for pheasant chicks, especially those species that have similar ecologies. In order to test this grey partridge chicks were imprinted and used in field trials together with the pheasant chicks. The study was extended to include data on the diets of wild skylark and lapwing broods to test the hypothesis that all species feed on similar invertebrates.

26 2 STUDY SITE AND GENERAL METHODS

2.1 Study site

Figure 2.1 Topographical map of Austria showing the location of the Seefeld estate (star) (Anon 2006).

All field work for this research was carried out on the Seefeld estate (48°42’45”N, 16°11’39”E), a 2,400 hectare arable farming estate located around Seefeld-Kadolz in the Weinviertel (“Wine Farthing”) of Niederösterreich (Lower Austria) (Figure 2.1). This is a low-lying agricultural region of north-east Austria close to the border of the Czech Republic. This region is part of an alluvium Tertiary basin composed of loess, an accumulation of sand, silt and clay (Egger et al. 1999). The soil type of the estate is loam consisting of 40 - 50% sand, 30 - 40% silt and 15 - 20% clay with a humus content of 2 - 2.5% and a pH value around 7.3 - 7.6. Couch grass ( Elymus repens ) dominates the grasses, especially as an initial coloniser of areas taken out of intensive cropping. Other grass species include Festuca and Poa species, cocksfoot ( Dactylis glomerata ) and timothy ( Phleum pratense ). Also common are agricultural weeds including thistles ( Cirsium species), sow-thistles ( Sonchus species), wild carrot (Daucus carota ) and thorn apple ( Datura stramonium ) amongst many others. A full vegetation list for the estate is given in Appendix I.

The majority of the estate (71%) is used for agriculture, with winter wheat being the dominant crop covering 37.1% of the arable area (averaged over 2007, 2008 and 2009). Spring wheat (3.0%), maize (14.6%), sugar beet (9.9%), winter (7.7%) and spring (6.6%) barley, oilseed rape (5.7%), potatoes (5.7%) and onions (0.5%) are also grown on the estate. North and east of these crop fields, on slightly higher ground, are 42 ha of vineyards producing international quality wines. The remaining land is taken up by coppiced woodland, rotational and long-term set-aside, and a large indoor pig farm. The land surrounding the estate is composed of further arable farmland and vineyards. The Seefeld estate is unusually large by Austrian standards where 89% of farms are small scale averaging 14 ha or less (Quendler 2005). The surrounding farms and their fields are managed in the traditional strip method with several different crops growing in each field whilst most of the estate’s fields consist of a monoculture or a single dominant crop type.

The principal benefits of using this site are two-fold. Firstly it allows the methodology to be tested on a farming site that is as ideal for gamebirds as any alternative. Previous studies of overwintering and breeding pheasant ecology have also been carried out on the estate providing a good background knowledge of the ecological system (Anderson 2002; Bliss 2004; Draycott et al. 2009). Secondly the use of imprinted chicks to investigate foraging in the field can only be carried out during warm, dry conditions. Being a land-locked continental country Austria’s weather is more predictable than in the United Kingdom, which allows more days in which to collect data; a significant factor with such a time-sensitive project. The average temperature over May and June is 16.3 °C with temperatures ranging from 6 to 37 °C (Draycott et al. 2009) with many days over 20 °C (Figure 2.2). Annual rainfall averages 485.8 mm with 25.9% of this occurring during May and June.

28 250 25 C) °

200 20

150 15

100 10

Rainfall in May and June (mm) 50 5 Average Average temperatureinMay and June( 0 0

Year Figure 2.2 Rainfall (columns) and average temperature (line) during May and June at the Seefeld estate.

The crop types and farming methods are similar to those used in the UK and the rest of Europe allowing some careful comparisons to be made. Whilst the climate is less variable than in Britain it has a similar range although in general with colder winters and hotter, drier summers. Another important difference is that there are fewer hedgerows, stone walls and fences compared to the UK with more tree lines and ditches marking field boundaries. Whilst the Seefeld estate has large fields, each consisting of a monoculture, such as are found in the UK, many of the surrounding fields are composed of traditional strip farming increasing the heterogeneity of the region during the late spring and early summer months.

The Hardegg family have managed the Seefeld estate since the fifteenth century and current management practices are designed to increase wild game populations on the estate. The principal game shot are the pheasant, European brown hare ( Lepus europaeus ), roe deer (Capreolus capreolus ), wild boar (Sus scrofa ) and several duck species. Numbers of pheasants and hares shot show a similar pattern over the years, possibly attributed to their sharing the same farmland habitats (Figure 2.3). Intensive predator control is primarily aimed against the red fox ( Vulpes vulpes ) and corvids. Larson traps were used to decrease the corvid populations until their use became

29 illegal. Numbers are now fairly consistent and are kept low by shooting. Foxes are shot and cubs killed by flushing with dogs, with consistent numbers being killed annually over the last 20 years (Figure 2.3). Besides rats (Rattus norvegicus ) and other small rodents, hedgehogs (Erinaceus europaeus ) are also a major egg predator of ground nesting birds and were present in high numbers during the 2009 study period (Pock, pers. comm.).

4500

4000

3500

3000

2500

2000

Numbers shot 1500

1000

500

0 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 Year

Figure 2.3 Bag records for pheasant (solid red), hare (solid orange), duck (broken green), fox (solid purple) and others (broken blue) on the Seefeld estate over the past 50 years.

Unusually for Europe no releasing of farmed pheasants takes place on the estate or surrounding area making the population of pheasants here purely wild. Austrian pheasant populations were at their peak in the 1960s but decreased in the 1970s when farming in Austria became more mechanized and pesticide use increased (Robertson 1997). Insecticide use is avoided on the Seefeld estate but herbicides are used routinely on the commercial crop fields and these are known to indirectly decrease invertebrate numbers by decreasing the variety of food plants available (Rands 1985; Sotherton and Robertson 1990; Marshall et al. 2003; Taylor et al. 2006). Bag records from shoots in Lower Austria in 1972 were at 18 pheasants per km² but decreased to four per km² by 2000; on the Seefeld estate, however, the harvest ranged from 16 to 54 birds per km² (Draycott et al. 2002). Figure 2.4 shows the decline in the number of pheasants shot against the increasing yields of winter wheat, both of which are due to

30 the intensification of agriculture. The estate’s spring population counts since the mid- 1990s show some areas with over 100 birds per km² and Robertson (1997) states that the pheasant breeding densities in the best areas of the Seefeld Estate were second only to those of Pelee Island, Canada, which had no mammalian land predators. Density of hen pheasants has on average increased on the estate since 1992 whilst the number of hens per cock has fluctuated around 3.2.

7000 4500

4000 6000 3500 5000 3000

4000 2500

3000 2000 1500 2000 ofNumberpheasants shot Wheat yield Wheat(kg/ha) yield 1000 1000 500

0 0

Year

Figure 2.4 Winter wheat yields (broken line) as a proxy for agricultural intensification and the number of pheasants shot (solid line) at the Seefeld estate over the past 50 years.

The Seefeld estate sits on reclaimed marshland, much of it lying along the Pulkau River upon which it relies for irrigation. This river, and the railway alongside it, runs west to east through the estate (Figure 2.5). During the 1950s the river was canalised, but during the “Trockenjahren” (“Arid Years”) of the 1980s the disadvantages of this were realised and during 1990s it was restored to a meandering course surrounded by wetland areas of reed beds and shrubs. Smaller streams and irrigation ditches cross the estate often emarginated by reeds. During this time the farm begam to use a more integrating management system reducing pesticide and fertiliser use and avoiding soil erosion with protection belts.

31

Figure 2.5 Field plan of the Seefeld estate. Towns of Obritz, Seefeld, Grosskadolz (together referred to as Seefeld-Kadolz) and Zwigendorf are labelled in capitals and named fields denote those belonging to the Seefeld estate. Estate farm tracks accessible by car are included as roads.

To help maintain wild game popultions sorghum is planted as a game crop to provide winter cover and the woodlands are coppiced with open rides being maintained. Supplemental feeding provides additional food for pheasants and deer during winter and spring. The flexible set-aside regulations in Austria allow game crops and cereal mixes with a rotational harvesting of strips which provides constant cover for the birds around the year and ensures a natural succession of newly-sown and established vegetation (Robertson 1997). The farm has 67 ha of long-term set-aside (Figure 2.6) which are to be left uncropped for 20 years, the first of these areas were removed from production in 1996, the lastest in 2001. Areas of sorghum are cut each March ensuring winter cover for game. The alfalfa and long-term areas of grass are cut every August whilst irrigation strips, banks and boundaries are cut when deemed necessary to prevent succession and maintain a healthy habitat. The benefits of these management practices are not limited to game species; avifauna observations reveal more than 85 species benefiting from pheasant habitat management (Anderson 2002) (also see Appendix II).

32

Figure 2.6 Example of an area of long-term set-aside on the Seefeld estate (Forsterwiese).

2.2 Chick foraging trials

Faecal analysis is the least invasive method of investigating diet and has been used successfully in many avian studies (Green 1984; Poulsen et al. 1998; Brickle and Harper 1999; Moreby and Stoate 2001; Palmer et al. 2001; Cummins and O'Halloran 2002; Butler 2007). In order to carry out a thorough examination of diet in specific habitats it is necessary to restrict the chicks’ foraging opportunities to a single habitat and to collect all faeces containing diagnostic fragments from that foraging session. In turn this can only be carried out using captive birds, however chicks that were allowed to forage in pens placed in the field showed high levels of stress when caught for faecal collection (Pyke 1989). To reduce this stress and allow natural foraging behaviour in this study, chicks were first imprinted onto a human handler who then took them to forage in a single habitat.

Very little work imprinting pheasants has been done (Kimmel 1985; Kimmel and Healy 1987; Regenscheid et al. 1987; Jalme et al. 2003), although other game species such as the northern bobwhite quail (Colinus virginianus ) (Palmer et al. 2001; Butler 2007), greater sage-grouse (Centrocercus urophasianus ) (Huwer 2004) and grey partridge (Herrmann and Fuchs 2006) readily accept human-imprinting and have been used in field studies. The methods used in these previous studies vary greatly due to

33 the aims of the research and the behaviour of the chicks. For this reason the methodologies used to both imprint the pheasant chicks and collect data from their foraging trials in this study first needed to be established

2.2.1 Imprinting

Pheasant eggs were obtained from the Velký Karlov game farm (Velký Karlov, Czech Republic) then incubated and hatched in a Brinsea Polyhatch and Brinsea Octagon 20 Advanced incubators. During incubation the temperature was kept at 39.5 °C in the Polyhatch or 37.7 °C in the Octagon and both maintained at approximately 45% relative humidity (RH). These temperatures are as per the manufacturer’s guidelines for these products and probably vary due to the different structures of the machines. Humidity was monitored by weighing six of the eggs (chosen at random) in each incubator and plotting weight loss over incubation. Healthy eggs loose 13% of their weight due to water loss over the incubation period, although the rate of loss can fluctuate during this time. Humidity was maintained through topping up water troughs below the eggs and adjusting ventilation of the incubator. In the Polyhatch eggs were set on their side and the rolling floor turned them twice hourly, in the Octagon eggs were either set on end or on their sides with automatic turning (through 90°) occurring on an hourly cycle. Turning was stopped 2-3 days before the expected hatching on day 24 and humidity was increased through the addition of extra water pans. Out of the six batches of pheasant chicks that hatched successfully over 2007 - 2009, five started hatching on day 24 and one on day 25. From one batch in July 2008 only a single chick hatched and two other eggs pipped then failed to hatch. Upon examination most eggs in this batch proved to be infertile. During the preceding batch (June 2008) many chicks died aged five to 10 days old, most probably from a parasitic infection of the egg. It was concluded that there was a problem with the game farm rather than our methods since previous and subsequent batches suffered no ill effects. The incubators were thoroughly washed in mild detergent and allowed to dry before each batch of eggs was set.

34

Figure 2.7 Imprinting and brooding the chicks during the first day.

Six to 12 hours after the chicks hatched they were transferred to a cardboard box (approximately 55 x 50 x 25 cm) for initial imprinting on the handler. Aluminium numbered legs rings were placed on the chicks to identify individuals. The imprinting process was conducted with the handler spending 8-10 hours a day sitting in with the chicks, calling softly to them and using hands to ‘brood’ them (Figure 2.5) (Kimmel and Healy 1987; Palmer et al. 2001).

Once they reached two to three days old the chicks were transferred to a brooder pen (150 x 135 x 50 cm) and imprinting continued. Temperature during imprinting was kept at 37 °C using a 250 W infrared bulb suspended over the box or pen. Chick starter crumb (purchased from Hrušovany and Jevišovkou) and water were provided ad libitum . Once outdoor trials began the time spent bonding with the chicks decreased unavoidably. From the second day chicks were fed mealworms ( Tenebrio molitor ) to help bond them to the handler and to introduce them to live food. At three and four days old the chicks were taken to forage on a rough lawn to introduce them to the natural climate and vegetation and to ensure they returned when called. This also allowed them to practice foraging before the field trials began. One hour of foraging outside prior to trials was aimed for but if weather prevented this 30 minutes was the minimum accepted. If at any stage a chick did not take to the imprinting and repeatedly made distressed ‘lost’ calls or refused to return to the handler that chick was removed from the others and housed elsewhere for the duration of the

35 experiments. When a chick was removed from the experiments or at the end of the trial period all leg rings were removed. Chicks were considered sucessfully imprinted if they would follow the handler during foraging practice and return to the handler promptly at the end of this practice. Chicks that took longer that five minutes to stop foraging and return to the handler were removed from field trials.

2.2.2 Field trials

In 2007 three ‘broods’ of five day old chicks were taken by different handlers to separate locations and allowed to forage for 30 minutes whilst the handlers stood still to see if the chicks would determine their own foraging path (Butler 2007). For one handler two chicks disappeared into the vegetation making lost calls, for another one chick refused to stay close, lost called continually and eventually had to be chased before collection. The ‘brood’ with the imprinter however stayed within 1.5 m foraging happily for the duration of the test. From this it was concluded that the handler must be involved with imprinting the chicks (subsequent batches imprinted by two handlers accepted both) and that they will follow the handler rather than choosing their own route through the crop. It was decided that the handler should walk along a random transect in each habitat with pauses to allow the chicks plenty of time to forage. This trial run also highlighted the importance of testing the strength of the imprinting before taking chicks into the field. Over the three study years only six chicks out of the 178 used in field trials were lost in the field (3.4%) implying that the methods used for imprinting and field trials is successful. This is a much lower rate of loss than that in previous studies where 13.5% bobwhite quail (Butler 2007) and 19.2% greater sage-grouse (Huwer 2004) were lost in the field.

To ensure that all diagnostic parts found in their faeces came from the trial the chicks were kept indoors and not fed mealworms for 24 hours before each trial (Palmer et al. 2001). All food was removed from the brooder two hours prior to the first trial to ensure feeding in the field. All trials were conducted between 12:00 and 19:30 on days when the air temperature was over 17 °C (or 20 °C if overcast) and ground vegetation was dry to the touch (Butler 2007). In each trial a ‘brood’ of four chicks were chosen at random and transported to the field site in bird bags and temporary leg rings allowed the identification of individual birds. All chicks used in trials were

36 between five and 12 days old since older chicks which were fledging were too difficult to collect without undue stress.

At the field site the ‘brood’ were placed at a predetermined random location and allowed to forage naturally. Where possible the sites were a minimum of 10 m from the boundary to avoid edge effects but this was impossible in some of the set-aside areas. The chicks were slowly walked along a 10 m transect moving two metre intervals every five to six minutes. If any chicks made lost calls or wandered too far they were called back then allowed to continue foraging. After 30 minutes all four chicks were collected as quickly as possible without scaring them. Thirty minutes was chosen as an optimal duration to ensure no fragments were lost in faeces in the field (Pyke 1989; Butler et al. 2004). The collection point was often placed on a tramline or sparse patch where the chicks could more easily be gathered. The chicks were then transported back to the laboratory in individual bird bags as this was deemed the least stressful method of transport. If any chick took too long to return or had to be chased it was removed from further trials. To increase the number of trials possible chicks were reused in later trials making sure that over 24 hours had elapsed between them and that each ‘brood’ was composed of different chicks.

During 2008 and 2009 certain aspects of chick behaviour during field trials were also recorded. At each five minute count the approximate distance of each chick from the handler was also recorded, with zero being a chick touching the handler’s shoes. Further distances were estimated to within the nearest metre. The number of chicks visible was also recorded at these five minute intervals starting five minutes into the trial and ending at 25 minutes. This can be linked to the vegetation structure and how much visual cover from predators each habitat provides. Any other interesting observations were noted for discussion.

2.2.3 Faecal collection and analysis

Following each trial ‘broods’ were kept in collection pens (30 x 40 x 29 cm) overnight with chick crumb and water provided ad libitum . The pens were constructed from 1cm wire mesh with a wire mesh floor raised 2 cm to allow the droppings to collect on a sheet below. Any chick that wandered into a different habitat type before

37 collection was rejected straight away as the faecal sample was deemed potentially contaminated. After 18 hours all faecal matter was collected together with any found in the bird bags and stored in plastic zip-lock bags in the freezer. The pens were then cleaned for the next ‘broods’.

The frozen faecal samples were transported back to the UK where the faecal material was analysed according to Moreby (1988). The faecal matter was thawed and washed through a 210 µm sieve to remove the uric acid and any fine debris that would cloud the sample. The cleaned faecal matter was then stored in IMS (Industrial Methylated Spirits) prior to analysis.

Each faecal sample was analysed separately and all equipment thoroughly cleaned in between samples. The faecal matter was transferred to 90 mm Petri dishes marked with a 10 mm grid and examined under a binocular microscope at approximately x16 magnification. Invertebrate fragments were identified using published guides (Ralph et al. 1985; Moreby 1988; Shiel et al. 1997) and personal communications with S. Moreby (GWCT), D. Quicke (Imperial College London) and J. Flanders (University of Bristol). All fragments were identified to order and family where possible.

2.3 Invertebrate sampling

Following each chick trial conventional invertebrate samples were taken from each site to compare with the faecal sample. Sweep net samples were taken in 2007, 2008 and 2009 and vacuum samples in 2008 and 2009. Previous research has shown the difference between suction sampling and chick diet resulting from chick preference (Potts and Aebischer 1991; Moreby et al. 2006), but many invertebrate studies use sweep-netting rather than suction sampling for reasons of cost or practicality (Bechinski and Pedigo 1982; Cooper and Whitmore 1990). Since pheasant chicks might be expected to forage solely at ground level it would appear vacuum sampling is more appropriate, however on frequent occasions chicks were observed taking insects from the vegetation as high as they could reach, even jumping for prey items that had caught their attention. In the denser grass clumps chicks were also observed climbing over rather than through the vegetation demonstrating that they are not restricted to ground dwelling prey.

38

The total number of invertebrates caught by sweep netting is generally higher than by vacuum sampling (Costa and Corseuil 1979; Randel et al. 2006), as a single sweep samples both a greater area and a greater proportion of the habitat. The smaller sampling area of a vacuum sampler means more samples need to be taken from a habitat in order to accurately assess the invertebrates present. The vacuum sampler only collects small invertebrates at ground level (pers. obs. of larger beetles not being collected) whereas the sweep net only collected invertebrates from the vegetation, albeit across a greater vertical distribution. Studies comparing the techniques vary in their findings depending on the invertebrate taxa considered and the habitat sampled (Banks and Brown 1962; Costa and Corseuil 1979; Bechinski and Pedigo 1982; Harper et al. 1993; Buffington and Redak 1998; Standen 2000). There appears to be strong correlation between the methods for many invertebrate taxa (Banks and Brown 1962; Reddersen 1997; Buffington and Redak 1998; Standen 2000), however differences do occur, particularly for certain groups within the Coleoptera (Staphylinidae), Diptera, Hemiptera (Auchenorrhyncha) and Araneae (Linyphiidae). Various studies have concluded that sweep netting is appropriate to use in grassland and crop fields (Fenton and Howell 1957; Banks and Brown 1962; Bechinski and Pedigo 1982; Törmälä 1982) and since the structure of the different habitats used in this study are similar, bias from sweep netting should be equal across them making this method acceptable (Törmälä 1982). The benefit of also using vacuum sampling is that it will also collect the ground invertebrates that are available to the chicks and the use of both sampling methods can provide more complete data on insects available to the chicks (Standen 2000).

Along each transect one sweep net sample consisted of ten sweeps of 180° evenly spaced. In 2008 a modified McCulloch leaf blower was used and in 2009 a Vortis Insect Suction Sampler (from Burkard Manufacturing Co. Ltd.). Both samplers had a collecting area of approximately 0.2 m2 and 60 seconds of sampling was performed along the 10 m chick transects: sixty seconds continual suction of the modified leaf blower and six 10 second sucks of the Vortis. Samples were transferred to zip-lock plastic bags which were labelled and frozen prior to sorting and identification. All invertebrates were identified at least to the level of order or family for Coleoptera and certain Hemiptera groups (Chinery 1993), more detailed identification was deemed

39 unnecessary since this was the lowest level at which faecal fragments could be identified.

2.5 Vegetation survey

A vegetation survey was carried out at each field site following the chick trials. Four different measures of vegetation structure were each taken at five points along the transect to best quantify the habitat with reference to chick behaviour. The measurements were taken to either side of the transect to avoid any effect of prior trampling. Two standard measures, percent vegetation cover and vegetation height, were taken along with other more biologically relevant measures. Vegetation height was measured using a technique modified from Robel (1970) using a pole 150 cm tall marked at 5 cm intervals. This pole was viewed from a height of 1 m and a distance of 4 m (Anderson 2002) and the lowest 5 cm section which was at least half-covered was recorded to eliminate bias from rare tall stands. The percentage of vegetation cover was estimated using a 0.25 m² quadrat subdivided into 25 equal squares. This quadrat was also used to measure the ratio of dicotyledons compared to monocotyledons. The vegetative structure of these groups is very different since dicotyledons tend to have wide open leaves compared with the blades of most monocotyledons. Many phytophagous invertebrates specialise on different plant types (Schoonhoven 2005) so it may be that this ratio has an effect on chick diet.

Vegetation density at chick height was measured indirectly by measuring chick visibility using a laser pointer mounted horizontally five centimetres above the ground. The distance between the laser and the furthest point it hit was measured at each cardinal direction. This method was used to get an estimation of a chick’s line of sight which is useful with regard to both prey detection and chick movement (Gillings 2004). The density of a crop at chick height will also affect both the cover the vegetation provides and how easily a chick can move through the habitat. Very dense habitats may slow down a chick’s movements (pers. obs.) and remain waterlogged after rain which can increase the risk of hypothermia (Robertson 1997).

The crop’s efficiency as visual cover from predators was assessed using the visual obstruction technique more commonly used to assess nest cover (Anderson 2002).

40 Visual obstruction is ranked from one to four with one being 0-25% covered and four being 75-100% covered. In this study a tennis ball (being approximate chick size) was viewed from a distance of 1m from two angles: directly above and from the side at a height of 0.5 m (Figure 2.6). This represents how visible the chicks would be to both avian (top-down view) and mammalian (side view) predators.

Figure 2.8 Measuring the visual obstruction score of a chick sized tennis ball.

41 3. DIFFERENTIAL RECOVERY OF INVERTEBRATE FRAGMENTS

Direct analysis of a bird’s diet is more biologically relevant than taking insect samples from the foraging habitat. Several techniques are available to determine what has been consumed: dissection of the digestive tract, flushing of the tract with saline, ligature use to prevent swallowing, faecal analysis and direct observation. The latter two techniques are the least invasive; however, direct observation is often impossible in the field.

Dietary reconstruction from faecal analysis relies on identifying fragments that have survived digestion. Since the composition of these diagnostic fragments varies the rate of digestion will vary between different groups; hard, chitinous fragments more commonly survive than softer parts. To account for this differential digestion it is possible to establish factors with which to correct the raw fragment counts (Custer and Pitelka 1974; Green 1984; Green and Tyler 1989; Butler 2007). Correction factors for pheasant chicks foraging in Lower Austria are here established, using laboratory feeding trails, which are to be used during the rest of this study.

3.1 Introduction

To determine what foods items a bird has consumed there are a variety of techniques available, the most invasive of these being by post mortem examination of the contents of the digestive tract (crop and/or gizzards). In some studies the birds have been found dead by other means (Ford et al. 1938), but in others birds have to be purposely killed (Palmer et al. 2001; Butler et al. 2004; Butler and Gillings 2004; Smith and Burger 2005). This raises ethical issues surrounding the treatment of vertebrates in research and is almost invariably unacceptable in the study of rare or endangered species. Some studies circumvent these issues by the use of neck collars (ligatures) to collect crop samples from live birds (Orians 1966; Wilson 1966; Robertson 1973; Dyrcz and Flinks 2003), or by flushing the digestive tract (Moody 1970; Jenni et al. 1990; Gionfriddo et al. 1995; Hess 1997). These methods are highly invasive and mortality rates with flushing vary greatly between different bird species from 0% up to 30% (Durães and Marini 2003) making its use in some studies unacceptable. The use of ligatures has been observed to modify behaviour of the

42 parent birds (W ilson 1966; Robertson 1973) and the begging frequency of nestlings (Orians 1966; Johnson et al. 1980). They can also increase gasping rates (Johnson et al. 1980) and mortality, especially in younger chicks, although mortality rates again vary greatly between species (Wilson 1966; Mellott and Woods 1993) . Samples taken using ligatures are not unbiased since small items can often still pass the ligature and larger items may be coughed up or taken by the parent (Orians 1966; Robertson 1973; Johnson et al. 1980; Mellott and Woods 1993) . Ligatures also have the disadvantage that only food items from a single foraging foray are collected (Moreby and Stoate 2000) biasing any generalisations that are drawn about diet .

A non-invas ive and therefore more ethically acceptable alternative is the a nalysis of faecal samples to determine diet by identifying invertebrate fragments and/or seeds that have survived digestion. This method has been used successfully in many studies of both wild birds (Green 1984; Poulsen et al. 1998; Brickle and Harper 1 999; Moreby and Stoate 2001; Cummins and O'Halloran 2002) and captively reared birds (Green and Tyler 1989; Pyke 1989; Palmer et al. 2001; Butler 2007). This technique collects items from a longer time frame compared with the use of neck collars (Moreby and Stoate 2000) and so often incorporates a series of foraging trips.

All these techniques req uire the identification and counting of the number of food items found in the sample. The problem of using faecal samples is that soft bodied prey items such as Collembola will be completely digested or fragmented beyond recognition (Moreby and Stoate 2000) . Hard or chitinous fragments such as mandibles, chelicerae, femur and tibia will pass through the digestion tract relatively intact and can be used to identify the prey eaten (Ralph et al. 1985; Moreby 1988; Shiel et al. 1997) but some of these will still be completely broken down or retained within the digestive tract. The methods for accou nting for this differential digestion of prey items vary with some studies calculating factors for the different invertebrate taxa relative to a single taxa (Custer and Pitelka 1974; Green 1984) and some omitting them entirely (Poulsen et al. 1998; Brickle and Harper 1999; Mo reby and Stoate 2001; Cummins and O'Halloran 2002). The most robust method uses the following formula devised by Green & Tyler (1989):

Where the proportion in the diet of prey type j (Pj) is related to the fragment count (n) for the different prey items, the number of fragments recovered in the faeces per invertebrate eaten, also termed the correction factor, (f) and the number of identifiable invertebrate taxa eaten (K). In order to use this formula the correction factor (f) is required. Since it is unlikely that digestion rates will be identical across all bird species it is advisable to calculate these factors for each new species studied. Intraspecific variation may also occur due to different geographical regions or dietary differences between habitats making it more accurate to calculate independent correction factors.

3.2 Methods

Thirty-five one day old chicks were bought from the Velký Karlov game farm in July 2008. They were housed in a brooder pen (1.5 x 1.35 x 0.5 m) kept at 37 °C using a 250 W infrared bulb with food and water provided ad libitum . Chicks were used in feeding trials at five, seven, nine and 11 days old. Food was removed at least two hours prior to the trials to encourage chicks to eat during each trial. On each day the trials were run, 12 randomly selected chicks were placed as pairs into six individual boxes (approximately 30 x 40 x 29 cm) and offered defrosted invertebrate food. In total 24 pairs of chicks were used in these trials. With the exception of the Formicidae, insect prey items were obtained from cultures kept at Imperial College London and stored frozen. Formicidae were collected from wild ant nests found around the site and stored frozen. Every invertebrate offered was whole, as far as could be determined by a precursory examination. Each day three boxes were given a low quantity of food and three a high quantity (Table 3.1) to take into account different digestion rates after different quantities were eaten. Starting times of the feeding trials were staggered at 13:00, 13:30 and 14:00 with one high quantity and one low quantity trial starting at each time. This staggering reflected the foraging times used in the field trials and allowed time for a single researcher to conduct all laboratory trials.

44 Table 3.1 Quantities of invertebrates used during feeding trials and the diagnostic fragments that can be obtained from each with number of fragments per individual.

High Low quantity quantity Diagnostic fragment Diptera small Drosophila 10 5 Femur (6), wing (2) large Musca 5 0 Femur (6), wing (2) Coleoptera small Trilobium 50 5 Femur (6), tibia (6), mandible (2) medium Dermestes 5 1 Femur (6), tibia (6), mandible (2) large Tenebrio 5 0 Femur (6), tibia (6), mandible (2) Lepidoptera Ephestia 10 2 Mandible (2) Hymenoptera Formicidae 10 5 Femur (6), tibia (6), mandible (2)

Chicks were given 30 minutes to eat the insects before being removed to collection pens (30 x 40 x 29 cm) and given chick crumb and water ad libitum to reflect the method used during field trials. The pens were constructed from 1 cm wire mesh with a wire mesh floor raised 2 cm to allow the droppings to collect on a sheet below. Any insects not eaten were counted then disposed of. Faeces were collected from the pens at one, three, six, 18 and 24 hours and stored in separate plastic zip-lock bags before being frozen. At 24 hours the chicks were removed from the pens which were then cleaned for the next trial. Due to the limited number of chicks available 13 chicks had to used a second time although in different pairings and after a minimum of 96 hours.

The frozen faecal samples were transported back to the UK where the faecal material was analysed according to Moreby (1988). The defrosted faecal matter was washed through a 210 µm sieve removing the uric acid and any fine debris that would otherwise cloud the sample. The cleaned faecal matter was then stored in IMS prior to analysis. The faecal matter examined in 90 mm Petri dishes marked with a 10 mm grid under a binocular microscope at approximately x16 magnification. Fragments were identified back to each taxa fed during the trial. Each faecal collection was analysed separately and all equipment thoroughly cleaned in between samples.

Accumulative recovery was plotted for each fragment type to determine whether collecting faeces from field trials after 18 hours is acceptable. Differences in total recovery (over 24 hours) for fragments from chicks offered high or low quantity diets were investigated in R (Ihaka and Gentleman 1996) using paired t-tests based on start time.

45 3.2.1 Correction factors

To determine the correction factors (f) to be used for imprinted pheasant chicks in the rest of this study the number of fragments recovered was divided by the number of that fragment eaten (number of insects eaten multiplied by the number of that diagnostic parts per insect) and averaged for each diagnostic type. This assumes that each insect was consumed in its entirety. With the Coleoptera, most commonly with Dermestes , there were six incidents when only the head or thorax and abdomen were eaten and in these cases the counts for mandibles or femur and tibia were adjusted accordingly. Fragment counts used were taken from the 18 hour collection since this is the time allocated for faecal collection during the field trials.

These factors were compared to those used in other studies (Custer and Pitelka 1974; Green 1984; Butler 2007) to determine appropriate values for those taxa not included in this feeding trial. By comparing which fragments had similar values to each other in these previous studies and by considering the size and nature of each fragment appropriate correction factors could be determined. Values for fragments from unidentifiable taxa were calculated from the averages of that fragment type.

3.3 Results

Of the 1311 insects offered only 664.5 (39.7%) were eaten by the chicks: 90 (66.7%) Drosophila , 13 (21.7%) Musca , 344.5 (56.7%) Trilobium , 16.5 (22.9%) Dermestes , 4.5 (7.5%) Tenebrio , 75 (52.1%) Ephestia and 91 (50.6%) Formicidae (various common species). In both the Diptera and Coleoptera it appears that a higher percentage of smaller species was consumed and there was no evidence of a change to larger items as age increased (Figure 3.1). Due to the small sample size at each age (n=3-6) no statistical analysis was attempted.

Cumulative recovery of fragments was plotted over the 24 hours (Figure 3.2) and indicates that for many fragments over 50% are lost during digestion. The plots also show a levelling off of the number of fragments recovered after 18 hours although there is a significant difference between the counts at 18 and 24 hours (t 277 = -4.20, P<0.001). Although significant, this difference is small since over 75% of all

46 fragments recovered were collected within 18 hours (Table 3.2). The largest discrepancy was for Tenebrio tibia and Dermestes mandibles, of which only 79.2% and 88.9% respectively were recovered in the first 18 hours. For all other fragments over 97% of those recovered were within the first 18 hours. The exception being that no Tenebrio mandibles were recovered over the 24 hours, possibly because only 4.5 were eaten.

25 Drosophila Musca 20 Trilobium Dermesties Tenebrio 15 Ephestia Formicidae

10 Average number eaten

5

0 4 5 6 7 8 9 10 11 12 Age (days) Figure 3.1 Variation in the number of insects eaten by chicks of different ages. Colour is used to denote the different Orders; broken line small items, long dashes medium items and solid lines large items within each order (where applicable).

Table 3.2 Number of fragments recovered at 18 hours compared with 24 hours. Prey item Diagnostic Fragment recovery at 18h fragment (as % of total recovery) Drosophila Wing 100.0 Leg 100.0 Musca Leg 97.1 Trilobium Femur 98.5 Tibia 98.0 Mandible 99.6 Dermestes Femur 98.2 Tibia 100.0 Mandible 88.9 Tenebrio Femur 100.0 Tibia 79.2 Mandible - Ephestia Mandible 100.0 Formicidae Femur 98.8 Tibia 98.0 Mandible 97.6

47

(a)

(b)

(c)

Figure 3.2 Cumulative proportion of fragments returned over 24 hours from the faeces of hand-reared pheasant chicks. ( a) Diptera fragments ( Musca and Drosophila ), (b) Trilobium fragments, ( c) Dermestes fragments. Eighteen hour mark used during field trials shown bbyy vertical line. (d)

(e)

(f)

Figure 3.2 (cont.) Cumulative proportion of fragments returned over 24 hours from the faeces of hand-reared pheasant chicks. (d ) Tenebrio fragments, (e) Ephestia fragments, (f) Formicidae fragments. Eighteen hour mark used during field trials shown by vertical line. * ** * ***

Figure 3.3 Proportion of insect fragments returned (± standard error) when offered high quantity (n = 12) and low q uantity (n = 12) diets (with standard errors). * indicates significance at α = 0.05, ** at α = 0.0 1, *** at α = 0.001.

Overall the proportion of fragments returned was influenced by the number of insects offered (Figure 3.3) with a higher proportion returned when fewer insects were offered (t = -5.36, P < 0.001). This effect varies with the insect and fragment type as most show no significant difference in return rate with respect to the number offered. In part this may be due to the high variation in the number eaten compared with the number offered. Trilobium ma ndibles are recovered at a greater rate when offered a smaller number of insects (t = -2.31, P < 0.05) as are Formicidae tibia (t = -2.66, P < 0.05) and femur (t = -3.60, P < 0.01).

3.3.1 Correction factors

The number of identifiable fragments recovered after 18 hours was used in conjunction with Green and Tyler’s (1989) formula to calculate the correction factor (f). Factors were compared to those found in other studies and these comparisons were used to est ablish factors for taxa not included in this study (Table 3.3). For example since the correction factors established for the pheasant closely resemble d those calculated for the northern bobwhite quail ( Colinus virginianus ) in America (Figure 3.4) (Butler 2007) this justified the use of Bulter’s other values for these other taxa: Araneae, Neuoptera , Hemiptera, Orthoptera and Isoptera . Table 3.3 Correction factors (f) to be used in dietary reconstruction. Taxa Fragment F Araneae Fangs 1 1.09 Pedipalp 2 1.09

Neuroptera Fangs 2 2.18

Diptera Wing 0.05 (small) Leg 0.13 (large) Leg 2.57 (Empididae) Front tibia 3 0.86

Hemiptera (Aphididae) Tibia 4 0.13 (Homoptera) Hind tibia 1 0.71 Leg 5 2.13 (Heteroptera) Front tibia 1 0.71 Labrum 5 0.36

Orthoptera Mandible 1 0.72

Isoptera Mandible 1 0.9

Lepidoptera Mandible 0.53

Hymenoptera Femur 3.14 Tibia 2.86 Mandible 1.06 Fore-wing 6 0.05 (small) Leg 4 0.13 (Tenthredinidae Larvae) Mandible 7 0.53

Coleoptera 10 Femur 2.11 Tibia 4 Mandible 0.58 (Carabidae, Front tibia 8 1.33 Scarabidae) (Elateridae) Peg 9 0.29 (Chyrsomelidae larvae) Mandible 7 0.53

Unknown/other Femur 9 2.46 Tibia 10 3 Mandible 10 0.72

1From Butler, 2worked out from Araneae fang, 3worked out from large Diptera leg, 4worked out from small Diptera leg, 5worked out from Homoptera hind tibia, 6worked out from Diptera wing, 7worked out from Lepidoptera mandible, 8worked out from Coleoptera tibia, 9worked out from Coleoptera mandible, 10 average taken.

51

Figure 3.4 Compariso n of correction factors (f) calculated for the pheasant (n = 24) (with standard error) and bobwhite quail (Butler 2007).

3.4 Discussion

After 18 hours the recovery rates of most fragments types declined, in many cases to zero or close to zero. In all cases over 75% of fragments were returned within the first 18 hours; 79.2% of Tenebrio tibia and 88.9% Dermestes mandibles were recovered. No Tenebrio mandibles were recovered over the 24 hours. For all other fragments over 97% of those recovered were within the first 18 hours. This validates the use of 18 hours for faecal collectio n, since very little data would be gained after this time. A longer collection period would lead to the loss of a day of field trials, a serious problem with such limited time. With more space, money and , more importantly , field assistants, collection time could be increased.

The overal l proportion of fragments returned var ied with the number of insects offered, although this was influenced by only a few fragment types, predominantly from the Formicidae. This implies that pheasants may be able in some way to alter their digestion based on available diet although the smal l scale of this study makes such links tenuous. The avian digestive tract is very flexible and various species are able to modulate their digestive enzymes, absorption rate, retention time and gut size based on the quantity and quality of food available (Karasov 1996). Due to the variation in the number of insects eaten compared to the number offered these findings must remain speculative. There are two main reasons why this discrepancy exists; firstly that the chicks were too well fed prior to the trials to eat the insects. Secondly, the chicks’ stress levels may have been elevated to such a degree that they were oblivious to the food items. It is likely that a combination of both factors was at fault, although from observations the chicks behaved in an agitated manner in their feeding boxes, running to and fro and making distressed calls. In future studies it is worth bearing in mind the importance of acclimatising the chicks to the study pens before the commencement of feeding. In this study space was limited meaning chicks had to be transferred between the brooder pen, individual feeding boxes and collection pens, which is likely to have increased stress levels.

Unfortunately it was impossible to know how many insects were encountered by the chicks during the field trials therefore the results from the high and low quantity trials were averaged to produce the correction factors. These correction factors calculated for the pheasant chicks closely resemble those calculated for the bobwhite quail in a previous study (Butler 2007) indicating that despite these two species being in different families (Phasianidae and Odontophoridae respectively), different continents (Europe and America) and of different sizes, their digestive systems work in similar ways. This justifies the use of factors calculated for one Galliforme with another foraging on invertebrates in a similar habitat. It also implies that feeding strategy and diet might be more accurate predictors of digestive rates than taxonomy, i.e. that the digestive system is adapted to the foraging niche of animal. Analogous characteristics such as bill size and shape often occur when birds forage on similar diets (Beecher 1951; Lack 1983; Lovette 2008) and other examples of convergent evolution are found throughout nature (eg. (Gregory 1951; Werdelin 1986; Diamond 1991; Pettigrew 1991).

53 4 THE DIET AND FORAGING BEHAVIOUR OF FARMED AND WILD STRAIN HUMAN-IMPRINTED PHEASANT CHICKS

The use of human-imprinted chicks to investigate avian diet is becoming increasingly popular (Palmer et al. 2001; Huwer 2004; Herrmann and Fuchs 2006; Butler 2007) since it provides more biologically relevant results than traditional invertebrate sampling techniques (Wolda 1990). This method relies on the assumption that results gathered using human-reared chicks are applicable to wild chicks (Butler 2007). The overall aim of this study is to use human-reared and -imprinted pheasant chicks to assess the foraging potential of different farmland habitats for wild broods. Since foraging and diet are known to be innate behaviours in pheasant chicks (Robertson 1997) the assumption is that farm-bred chicks raised inside on starter crumb have not lost this behaviour. To test this assumption a mixed batch of wild-strain and farmed- strain pheasant chicks were imprinted onto a human handler. Mixed broods were then used in field trials to determine if any behavioural or dietary differences occurred. Faecal samples collected in previous years from the estate were also tentatively compared with samples gathered during this study.

4.1 Introduction

When considering the value of habitats for breeding birds it is important to consider food availability within these habitats. Young chicks require a high quantity of invertebrates in their diet for successful development (Offerdahl and Fivizzani 1987; Savory 1989; Dahlgren 1990; Ohlsson and Smith 2001; Liukkonen-Anttila et al. 2002; Southwood and Cross 2002) yet traditional methods of invertebrate sampling often fail to take account of the microhabitats used by different birds (Wolda 1990) and invertebrates (Gillott 1995), or of any preference shown by the birds (Mastrota and Mench 1995; Hartley et al. 1999; Gamberale-Stille and Tullberg 2001; Moreby et al. 2006). It is therefore important to find out what birds are actually eating in these habitats. There are several ways in which this can be achieved. The direct observation of what invertebrates are eaten sounds simple but requires a great deal of skill and luck to be able to successfully identify what a bird has picked up and whether the item is then consumed or not (Regenscheid et al. 1987; Herrmann and Fuchs 2006). A range of techniques have been developed for investigating the contents of the

54 digestive tract ranging from dissection of specimens (Ford et al. 1938; Palmer et al. 2001; Butler et al. 2004; Smith and Burger 2005) to the use of emetics, flushes or neck-collars to collect a sample of what has been eaten (Orians 1966; Wilson 1966; Moody 1970; Robertson 1973; Gionfriddo et al. 1995; Hess 1997; Durães and Marini 2003; Dyrcz and Flinks 2003). Alternatively, faecal samples can be collected and invertebrate remains identified (Green 1984; Pyke 1989; Poulsen et al. 1998; Brickle and Harper 1999; Moreby and Stoate 2001; Palmer et al. 2001; Cummins and O'Halloran 2002; Butler 2007).

Several studies are now combining these techniques with imprinting the chicks onto human handlers to allow the foraging habitat to be controlled and ensure all items consumed are counted (Palmer et al. 2001; Huwer 2004; Smith and Burger 2005; Herrmann and Fuchs 2006; Butler 2007). One drawback of imprinting is that not all bird species can be used; altricial chicks which rely on feeding by their parents are unsuitable for such studies. On the other hand precocial chicks such as gamebirds (Galliformes) are able to walk soon after hatching and the majority of groups search for their food without parental assistance (Starck and Ricklefs 1998). Phasianidae chicks (including the pheasant) hatch covered with downy feathers and within hours are up and following their mother. Although she does not feed them her chicks are still reliant on her for warmth (Offerdahl and Fivizzani 1987; Gdowska et al. 1993; Robertson 1997; Starck and Ricklefs 1998) and will remain with her until they are able to fend for themselves. The use of imprinted gallinaceous chicks in studies relies on the assumption that the diet and foraging behaviour of these chicks accurately reflects that of the wild chicks (Palmer et al. 2001; Huwer 2004; Butler 2007). Although this assumption is based on experience and observation of game chicks it is rarely tested. Butler (2007) investigating dietary differences between wild and imprinted bobwhite quail found that this assumption holds at the level of order. Slight discrepancies within orders can be explained by encounter rates or the fact that the wild chicks could not afford to be so fastidious in their choice due to their need for such a high number of invertebrates in their diet. It is a different matter with other aspects of behaviour however: reared pheasants, grey partridge and bobwhite quail have lower survival rates than wild birds due to decreased predator avoidance behaviour (Dowell 1990; Robertson 1997), wild pheasants are better fliers than reared

55 and released ones (Robertson et al. 1993) and hand-reared hen pheasants abandon their nests at a higher rate than wild hens (Sage et al. 2003).

Differences between wild and imprinted chicks may be due to the loss of parental stimuli, a loss of inherited skills, or a mixture of the two. Since hen pheasants play no active role in the foraging of their chicks other than choosing the foraging location it may be assumed that any differences will be due to a loss of inherited skills within a farmed strain. To test this hypothesis, chicks from farmed and wild eggs were raised together and imprinted on a human handler. Feeding trials were carried out in different arable habitats to determine if the foraging behaviour and diet of these two strains differed significantly.

4.2 Methods

During April and May 2008 eggs were collected from wild pheasant nests found around the Seefeld estate by researchers and farm workers. Due to the high temperatures at that time eggs were stored temporarily in a fridge (approximately 5 ºC) or cool box (approximately 10-15 ºC), then transferred to a wine cellar (ambient temperature approximately 11 ºC) prior to incubation. Pheasant eggs were bought from the Velký Karlov game farm and incubated along aside the wild eggs in the Brinsea Polyhatch and Brinsea Octagon 20 Advanced incubators (as described in Section 2.2.1). Each incubator contained both wild and farmed pheasant eggs separated by a wire fence. Over the two months 114 farmed eggs and 78 wild eggs were incubated with the majority of the wild eggs being collected during May.

Newly hatched chicks to be used in field trials were imprinted as described in Section 2.2. Wild-strain chicks had white numbered rings and farmed-strain had blue and red numbered rings to identify their origin. Chicks from both strains were raised and imprinted together to ensure any differences found were due to origin not husbandry. During May and June 20 field trials were conducted each using two wild-strain plus two farmed-strain chicks chosen at random. Each chick was marked on their back with permanent marker pen before each trial, wild-strain with green and farmed-strain with red, to allow the strains to be distinguished in the field. Foraging trials were

56 conducted on a range of sites as available: winter wheat (7), spring wheat (4), summer barley (1), potato (1), maize (1), long-term set-aside (3) and game crop (4).

4.2.1 Diet

Faecal samples were collected for each strain by using two collection pens per trial. Samples were collected and analysed as in Section 2.2.3 and the correction factors established in Chapter 3 were applied. The number of invertebrates and the number of invertebrate groups eaten by each strain were tested using paired t tests on normalised data (square root of the counts). Differences in dietary composition between the strains were tested using compositional analysis (Aebischer and Robertson 1993). Month and chick age were also included as explanatory variables in the model, then interactions and terms were removed stepwise to determine the simplest model. Invertebrates consumed were grouped into Araneae, Hemiptera, adult Hymenoptera, adult Coleoptera, ‘Larvae’ (containing Coleoptera, Lepidoptera and Tenthredinidae larvae) and ‘Other’ (containing Diptera and unidentified invertebrates). The proportion of each group in the diet was calculated by dividing each by the total and any zeros converted into 0.0001 to allow further calculations. To account for the unit- sum constraint of proportional data each group was then divided by ‘Other’ and the resulting values transformed using natural logarithms. These values were analysed in R (Ihaka and Gentleman 1996) using a Multivariate Analysis of Variance (MANOVA) having used the function cbind to bind the invertebrate groups into a single response variable.

Previous studies at Seefeld involving radio-tagging wild broods (Anderson 2002) yielded faecal samples from chicks aged 3-14 days old; seven samples were collected from 2001 and 12 from 2002. Some of these had already been processed and the raw counts were not corrected for differential digestion. For this reason compositional analysis was carried out (as above) comparing this uncorrected data with uncorrected data collected during 91 imprinted chick trials carried out in 2007 and 2008. A ranking matrix was produced comparing the log-ratios of all group pairings within the diet to determine which groups were causing any significant differences. The t values required in the matrix were calculated from F values generated by an Analysis of Variance (ANOVA) test. Using ANOVA rather than t-tests allows any interaction

57 between factors to be accounted for. The number of invertebrates and the number of invertebrate groups eaten by the wild and imprinted chicks was tested using Mann- Whitney tests since the sample size of the two groups is different.

4.2.2 Behaviour

Chick distance from the handler was recorded at five minute intervals throughout the trial starting five minutes into the trial and ending at 25 minutes. Zero was recorded if a chick was touching the handler’s shoes and further distances were estimated to within the nearest metre. Chick strain was identified by their red or green marks. The number of chicks of each strain visible was recorded at the same time.

Distance from the handler was tested in R using a Generalised Linear Model (GLM) using chick strain, age, habitat and the time into the trial as explanatory variables. Distance at each five minute increment was then tested using a GLM with chick strain, age and habitat as the explanatory variables. To test how visible the different strains were in the field a GLM was performed using a bound (again with cbind) response variable of the number of chicks visible and not visible at each time. Chick strain, habitat, time and age were used as the explanatory variables. All models were simplified step-wise to remove unnecessary terms and interactions.

4.3 Results

Forty-two (36.8%) of the farmed eggs hatched compared with 34 (43.6%) of the wild eggs. Five (14.7%) of the wild-strain chicks died within their first five days whilst only two (4.8%) of the farmed-strain chicks died within that time. Imprinting rates also varied between the strains with 85% of the farmed-strain and 100% of the wild- strain chicks successfully imprinting onto their human handler.

4.3.1 Diet

No significant difference was found between the number of invertebrates eaten by the chicks belonging to different strains (t 19 = 0.36, P = 0.72); nor was there any difference in the number of different groups eaten (t 19 = 0.84, P = 0.41) (Figure 4.1).

58 Here “groups” refers to the lowest taxonomic level each fragment could be identified to; mostly order or family. The compositional analysis shows that there is no significant difference between the proportions of different invertebrates found in the diets of the wild and farmed strain chicks (F 5,33 = 0.98, Wilk’s Λ = 0.87, P = 0.44)

(Figure 4.2). The only factor significantly affecting diet was month (F 5,34 = 6.63, Wilk’s Λ = 0.51, P < 0.001).

80 Farmed 70 (n=20) Wild 60 (n=20 50

40 Count 30

20

10

0 Number of invertebrates Number of invertebrate eaten groups eaten

Figure 4.1 The quantity and taxonomic diversity of invertebrate groups eaten by farmed and wild strain imprinted pheasant chicks (with standard errors).

59 1.00 0.00 0.00 Araneae Hemiptera 0.90 0.17 0.17 Larvae 0.80 0.05 0.04 Hymenoptera Coleoptera 0.16 0.70 0.19 Other

0.60

0.50

0.40 Proportion in diet Proportion 0.58 0.30 0.56

0.20

0.10

0.05 0.00 0.03 Farmed Wild Chick strain

Figure 4.2 The dietary composition of invertebrate groups eaten by farmed and wild strain imprinted pheasant chicks (2008).

Comparing data collected from imprinted chicks during 2007 and 2008 to wild faeces collected during 2001 and 2002 showed there was a significant difference in dietary composition (F 5,100 = 13.69, Wilk’s Λ = 0.59, P < 0.001). This effect was compounded by an interaction between brood type and habitat (F5,100 = 2.56, Wilk’s Λ = 0.89, P < 0.05). The main differences are that the wild broods ate significantly fewer Hymenoptera and more Araneida and larvae than imprinted chicks (Figure 4.3 and

Table 4.1). The wild broods also ate a greater number (w = 4734.0, n 1 = 91, n 2 = 19, P

< 0.05) and a wider range (w = 4425.0, n 1 = 91, n 2 = 19, P < 0.001) of invertebrates than the imprinted chicks (Figure 4.4).

60 1.00 0.05 Araneida 0.08 0.01 0.09 Hemiptera 0.90 0.04 Larvae 0.09 0.80 Hymenoptera Coleoptera 0.32 0.11 0.70 Other

0.60

0.50

0.40 Proportion in diet Proportion 0.61 0.30 0.51

0.20

0.10

0.04 0.05 0.00 Imprinted Wild broods Pheasant chicks

Figure 4.3 The dietary composition of invertebrate groups eaten by imprinted (2007 – 2008) and wild (2001 – 2002) pheasant chicks.

Table 4.1 Ranking matrix of the relative differences between the diets of imprinted (2007 – 2008) and wild (2001 – 2002) pheasant chicks. Within the matrix (+) indicated a row taxa is found at greater proportions in the diets of imprinted pheasant chicks, (-) means the opposite, triple sign indicates significance at α = 0.05.

Numerator Denominator Rank Hymenoptera Coleoptera Hemiptera Larvae Other Araneae Hymenoptera +++ +++ +++ +++ +++ 5 Coleoptera --- + +++ +++ +++ 4 Hemiptera --- - + + + 3 Larvae ------+ + 2 Other ------+ 1 Araneae ------0

61 300 * Farmed (n=91) 250 Wild (n=19)

200

150 Count

100

*** 50

0 Number of Number of invertebrate invertebrates eaten groups eaten

Figure 4.4 The quantity and taxonomic diversity of invertebrate groups eaten by imprinted (2007 – 2008) and wild (2001 - 2002) pheasant chicks (with standard errors). * indicates significance at α = 0.05, *** at α = 0.001.

4.3.2 Behaviour

There was no significant difference in the number of farmed or wild strain chicks visible over the trial (z = 0.37, P = 0.71). There was a significant difference in the distance of the chicks from the handler between the two strains (Table 4.2). The wild- strain chicks tended to stay closer to their handler than the farmed-strain chicks (Figure 4.5). Both types of chick also tended to move further away from their handler during the 30 minute trial, although the interaction between age and time into trial was more significant (Table 4.2).

1.7 Farmed (n=20) 1.6 Wild (n=20) 1.5

1.4

1.3

1.2 Distance fromDistance hander (m) 1.1

1 0 5 10 15 20 25 30 Time into trial (minutes)

Figure 4.5 Average distance between chicks and handler over the 30 minute field trial for farmed (broken line) and wild (solid line) strain imprinted pheasant chicks.

Table 4.2 Summary of the GLM investigating factors affecting the distance of imprinted pheasant chicks from their human handler. Estimate s.e. t value P value Chick strain -0.19 0.068 -2.79 <0.01 ** Time into tr ial -0.06 0.023 -2.40 <0.05 * Age -0.06 0.048 -1.27 0.20 Time:Age 0.01 0.003 2.83 <0.01 ** * indicate significance at α = 0.05, ** at α = 0.01

Separate GLMs at each five minute interval show that the effect of age is only significant for the latter half of the trial (Table 4.3). Older chicks tend to wander further from the handler over the duration of the trial (Figure 4.6).

63 2.5 5 days 2.3 (n=3) 6 days 2.1 (n=5) 1.9 7 days (n=4) 1.7 8 days 1.5 (n=3) 9 days 1.3 (n=3) 1.1 10 days (n=2) 0.9 Distance from handler (m) 0.7 0.5 0 5 10 15 20 25 30 Time into trial (minutes)

Figure 4.6 Average distance between imprinted pheasant chicks and handler over the 30 minute field trial at different ages.

Table 4.3 Summary of the GLMs investigating factors affecting the distance of imprinted pheasant chicks from their human handler at different time intervals. Five minutes: Estimate s.e. t value P value Chick strain -0.28 0.120 -2.34 <0.05 * Age -0.02 0.038 -0.49 0.63 Habitat -0.14 0.118 -1.18 0.24

Ten minutes: Estimate s.e. t value P value Chick strain -0.18 0.162 -1.28 0.28 Age < -0.001 0.051 -0.01 0.99 Habitat 0.031 0.157 0.19 0.85

Fifteen minutes: Estimate s.e. t value P value Chick strain -0.21 0.147 -1.40 0.17 Age 0.11 0.052 2.16 <0.05 * Habitat -0.34 0.153 -2.24 <0.05 *

Twenty minutes: Estimate s.e. t value P value Chick strain -0.10 0.138 -0.76 0.45 Age 0.11 0.046 2.29 <0.05 * Habitat 0.16 0.136 1.19 0.24

Twenty-five minutes: Estimate s.e. t value P value Chick strain -0.17 0.189 -0.91 0.36 Age 0.14 0.062 2.18 <0.05 * Habitat -0.15 0.186 -0.79 0.43 * indicates significance at α = 0.05

64 4.4 Discussion

Hatching rate was lower and post-hatching mortality higher in wild-strain eggs than in farmed eggs. This could be due to storage of the wild eggs prior to incubation (Ipek et al. 2006; Ko żuszek et al. 2009), a variation in fertility rates between wild and captive pheasants, or a difference in the condition of the wild and captive hen pheasants. Farmed pheasants will not have the stresses of hunger, weather, or predation and are able to be in top condition by the breeding season; in the wild, hen pheasants need to build up their resources prior to breeding (Dahlgren 1990; Robertson 1997; Draycott et al. 1998). Adverse weather or limited forage may decrease a wild bird’s fitness and thus the fitness of her chicks. The low hatching and survival rates for the farmed- strain pheasants were probably due to a common infection in the eggs (C. Davies, GWCT, per. comm. 2008). Over three days 11 chicks of about a week old died; the brood was given tylosin (a broad spectrum antibiotic) after which no further deaths occurred. Field trials were carried out with these chicks after discussion with the land owner since it is likely the infection is one present at low levels in the wild population.

It is known that hen pheasants play no active role in teaching their chicks to feed and that their foraging behaviour is instinctive (Robertson 1997). The lack of any differences in the diet of the two strains of chicks indicates that chick foraging and diet are behaviours so deeply innate in pheasants that they do not loose it in spite of being from captive stock. This in turn implies that it is acceptable to use pheasant chicks from commercial farms in studies investigating the diet of wild pheasant chicks. It is possible that the imprinting had a greater effect on foraging and diet than assumed here, but the lack of any evidence that hen pheasants teach their chicks to feed supports the belief that any effect of nurture on diet is insignificant. The major difference in foraging is that the human handler does not know the best micro-habitats that hen pheasants choose for their chicks to forage in. Brooding hens at Seefeld prefer to use set-aside areas, including game crop; high use of game crop and wetland areas seem to improve chick survival (Anderson 2002; Bliss 2004). Broods were most often found in agricultural fields due to this being the most prevalent habitat type available. Hill (1985) found that pheasant broods in England preferred to use rough grass and weedy areas as well as cereal fields. During this study chicks were taken to a mixture of habitat types known to be used by wild pheasant broods.

65

Ideally, diet and behaviour of wild broods as well as imprinted broods would be studied by radio-tracking hens and allowing imprinted chicks to feed in the same areas (Butler 2007). Radio-tracking allows the location of the night roost to be determined and faeces from wild chicks to be collected the following morning. Initially it was intended to collect faeces from wild broods by this method, but unfortunately financial constraints made it impractical. Comparing data collected from imprinted chicks during 2007 and 2008 with wild broods’ faeces collected during 2001 and 2002 showed there was a significant difference in dietary composition but this effect was compounded by an interaction between brood type and habitat. Faecal samples from both studies showed that Coleoptera were the most common order consumed followed by Hymenoptera, Hemiptera and larvae. In the previous study Hymenoptera and Diptera were found at a higher frequency in the faeces than the sweep nets, whilst the quantity of Hemiptera was greater in the sweep net samples than in the diet (Anderson 2002). These preferences are similar to those shown by imprinted chicks, which also prefer to eat Hymenoptera and tend to avoid the Hemiptera (Chapter 5).

These results must be viewed with caution since the wild broods had access to more foraging time and a wider foraging area that contained more habitat types than were investigated in the latter trials. This is illustrated by the greater number and diversity of invertebrate prey consumed by the wild chicks. Of the seven broods followed in 2001, three were found in more than one habitat type on the day faecal samples were collected. Reared chicks can afford to be more fastidious in their choice of prey since they have continual access to food in the laboratory. Wild chicks must eat a high proportion of the invertebrates they encounter to maintain healthy growth and development (Offerdahl and Fivizzani 1987; Savory 1989; Dahlgren 1990; Ohlsson and Smith 2001; Liukkonen-Anttila et al. 2002; Southwood and Cross 2002). There was also at least five years between the sampling dates of the wild broods’ faeces and the imprinted chick trials. Yearly fluctuations in insect communities due to their specific patterns of abundance and external factors including weather and farming practices, especially pesticide use (Drake 1994; Reddersen 1997; Marshall et al. 2003; Schowalter 2006; Taylor et al. 2006; Cole et al. 2007; Kishimoto-Yamada et al. 2009), may lead to the differences in diet discovered here.

66 The differences in imprinting rate and behaviour might be explained by a strong selective pressure for wild chicks to remain closer to their mother. A chick that wandered off in the wild would be at risk from exposure to the weather and to predators, and would be unable to survive long without brooding. Exposure is a common factor leading to chick death, either directly, or indirectly via starvation or predation (Hill 1985; Dahlgren 1990; Gdowska et al. 1993; Robertson 1997; Bliss 2004). Chicks that are reared on game farms have no need of a ‘mother figure’, as their environment is controlled to ensure no chilling occurs and that predators are excluded. Close observation of chicks in the laboratory and in the field disclosed no other behavioural differences between the two strains. Heinz (1973) found no difference in response to conspecific calls between pheasant chicks from wild and farmed eggs, supporting the finding here that many aspects of chick behaviour are deeply innate.

67 5 THE DIET OF PHEASANT CHICKS FORAGING IN DIFFERENT ARABLE HABITATS

Like many other farmland birds pheasant chicks require a high proportion of invertebrates in their diet for successful growth and development, particularly during their first two weeks. The intensification of agriculture has decreased the availability of insect prey. Set-aside areas originally implemented under the Common Agricultural Policy (CAP) have helped preserve invertebrate biodiversity. The cessation of set- aside subsidies has added another threat to invertebrates and insectivorous farmland birds; various agri-environmental schemes are now available which it is hoped will maintain and increase invertebrate biodiversity.

The merits of the various arable habitats have been assessed for chick foraging using human-imprinted pheasant chicks. The following crop types were investigated: winter sown cereals, spring sown cereals and non-cereal crops. No difference in diet was found between chicks foraging in different crop types; however, spring sown cereal has the densest vegetation. This study also highlights the importance of set-aside areas for foraging pheasant chicks. Set-aside areas provide a better quality of forage and greater cover from predators than the crop fields. In particular long-term set-aside appears to provide better foraging than sown game crops, probably due to its more open vegetation structure. The denser structure of sown set-aside may provide greater cover from predators yet may also limit the hen’s ability to spot danger and hinder the chicks’ foraging attempts.

5.1 Introduction

Arable land has changed over the past century as advances in mechanisation, agro- chemicals and crop genetics have allowed a more intensive agriculture to develop (Boag and Tapper 1992; Ewald and Aebischer 2000). The following changes, whilst increasing crop production, have led to a decline in farmland biodiversity. • Increased use of agro-chemicals (pesticides, herbicides and inorganic fertilisers) • Loss of hedgerows and field edges as field size increased

68 • Increased mechanisation leads to more disturbance of the soil and farmland • Changes in crop type allows sowing to occur in autumn removing overwinter stubble • Increased specialisation results in loss of habitat heterogeneity at a landscape scale • Loss of rotational or mixed cropping reduces soil fertility and increases habitat homogeneity • Higher grazing densities leads to changes in vegetation structure

These changes have all been discussed in detail in Chapter 1. The increased use of pesticides has led to a decline in invertebrate diversity due not only to direct causes from insecticides but also from the loss of food plants and habitat due to increased herbicide use (Rands 1985; Wilson et al. 1999; Taylor et al. 2006). Habitat homogeneity decreases the niches available and increased disturbance of the soil also decreases invertebrate biodiversity. The biodiversity of farmland birds is also decreased by these advances in agriculture, with different taxa being most affected by different changes depending on their ecology and behaviour (Siriwardena et al. 1998; Gregory et al. 2004; Newton 2004; Ahnström et al. 2008; Firbank et al. 2008). The loss of habitat homogeneity, weeds and over-winter stubble have been important factors for several farmland specialists (Fuller et al. 1995; Siriwardena et al. 1998). Many species have also been adversely affected by the decline in their invertebrate prey (Rands 1985; Siriwardena et al. 1998; Boatman et al. 2004). Many chicks, including pheasant and grey partridge chicks, require a high proportion of invertebrates in their diet . Invertebrates are high in protein and contain essential amino acids required for feather development (Savory 1989; Southwood and Cross 2002). Chicks on a low protein diet develop at a slower rate and often with deformities that cannot later be corrected (Ohlsson and Smith 2001).

Set-aside areas were introduced in 1988 under the CAP as a measure to halt combat overproduction. Set-aside became compulsory in 1992 and farmers got paid to keep a proportion of their farmed area out of production. In 2007 compulsory set-aside was reduced back down to 0% and in 2008 set-aside subsidies were abolished altogether (Europa 2007). The loss of these non-cropped areas is likely to have a detrimental

69 effect on farmland biodiversity (Kubišta 1990; Corbet 1995; Vickery et al. 2004; Kaiser et al. 2006; MacDonald et al. 2007) although it is hoped that the AES that have been introduced throughout Europe will help to retain some of these areas.

This study aims to investigate the invertebrate prey items consumed by foraging pheasant broods in different arable habitats to identify those best for brood rearing. A variety of crop types have been looked at: winter sown cereals, spring sown cereals and non-cereal crops. Previous studies have found preferences for both birds and invertebrates between different crop types; spring sown cereals consistently support greater abundances than other crop types (Chamberlain et al. 1999a; Dwyer 1999; Browne et al. 2000; Donald et al. 2001a; Wilson et al. 2001; Surmacki 2005). The importance of non-crop areas is also investigated. Many fields on the study site contain irrigation strips or long-term set-aside areas on a 20 year cycle. Several wetland areas have been created along the river; the grassy edges of these areas dry out during the early summer and have been included in this study. The term set-aside is used here to describe all non-cropped, non-wooded areas of the arable estate. Long- term set-aside areas are also referred to here as ‘grassy areas’ since they are composed primarily of self-seeded grasses. Due to the importance of game shooting on the estate, sorghum (Poaceae: Sorghum ) is planted as a game crop (sometimes known as a cover crop) to provide overwinter shelter. In 2007 four seed mixes were planted to test their potential as brood rearing game crops. Unfortunately, due to the changes in set-aside regulations, the mixes could not be planted in subsequent years. There are also a few areas of alfalfa on the estate that were used in these foraging trials. These areas are grouped together as sown set-aside areas or game crop for this study.

This study is unique in its use of human-imprinted chicks as the sampling method. The advantages and problems of this method are discussed at length in previous chapters. The main advantage is that it allows a scientific methodology to be applied to faecal analysis, a technique that often suffers from being purely observation of wild behaviour rather than experimental manipulation. It also allows the habitat to be sampled from the birds’ perspective, making it more biologically meaningful than other methods (Hutto 1990; Wolda 1990).

70 5.2 Methods

During the 2007, 2008 and 2009 breeding seasons (May - July) 366 pheasant eggs were bought from the Velký Karlov game farm and incubated in the Brinsea Polyhatch or Brinsea Octagon 20 Advanced incubators (as described in Section 2.2.1). Seventy-eight wild eggs were also collected in 2008 and their resu lts combined with the farmed eggs since no difference in chick diet was found (Chapter 4). Newly hatched chicks were fitted with numbered rings and imprinted to be used in field tria ls as described in Section 2.2.

During 2007 field trials were carried ou t in May, June and July; during 2008 field trials occurred only in May and June due to the July batch failing to hatch and in 2009 one series of field trials was carried out in June. Diffe rent farmland habitats were available for trials in May, June and Ju ly, and over the three years, depending on other research constraints, sowing and harvesting schedules . Four different seed mixes were tested as potential brood rearing cover in 2007 (Table 5.1) but unfortunately these trials could not be repeated in 2008 or 2009 due to changes in set-aside regulations.

Tables 5.1 Seed mixes sown as potential brood rearing cover providing food and shelter for chicks.

Winter sown cereals were harvested during late June and July, meaning these habitats had to be surveyed early in the breeding season. Sugar beet, potatoes, maize and the sown set-aside areas tended to emerge in early June and so were unavailable for the May trials. Long-term grassy set-aside areas were available throughout the season. The number of field trials conducted is shown in Table 5.2. Although this led to different crops being surveyed during different months this reflected the habitats available to wild broods at those times and so was deemed acceptable.

Table 5.2 Number of field trials in different farmland habitats over 2007, 2008 and 2009. Habitat Type Crop 2007 2008 2009 Total May June July May June June Crop Winter Wheat 3 7 2 6 18 cereal Barley 2 2 Spring Wheat 2 2 1 5 cereal Barley 3 1 3 7 Other Sugar beet 2 1 1 1 5 Potato 2 1 1 4 Maize 2 2 1 1 6 Set-aside Natural Grass 4 5 4 7 2 22 Sown Sorghum 4 2 4 2 12 Seed mixes 4 8 12 Alfalfa 2 1 3

The value of different habitats was assessed in three stages, firstly looking at different commercial crops: winter sown cereals (wheat and barley), spring sown cereals (wheat and barley) and other crops (sugar beet, potato and maize). The value of non- crop areas was then assessed by comparing all commercial crop fields with all non- crop habitats. Finally the merits of different set-aside schemes were investigated, both long-term set-aside and sown game or cover crops.

5.2.1 Diet

Faecal samples were collected as in Section 2.2.3 and correction factors from Chapter 3 applied to the raw fragment counts. The number of invertebrates eaten and the number of invertebrate groups eaten in different habitats were tested using Student’s t-tests or Analysis of Variance (ANOVA) on normalised data (square-root of the counts). Tukey’s pairwise comparisons were performed as post-hoc tests with ANOVA to determine where significance lay. Compositional analysis (Aebischer and Robertson 1993) was carried out to determine whether chick diet varied significantly

72 between the habitat types. Month, Year and Chick Age were also included as explanatory variables in the model, interactions and terms were removed stepwise to determine the simplest model. Invertebrate prey were grouped into Araneae, Hemiptera, adult Hymenoptera, adult Coleoptera, ‘Larvae’ (containing Coleoptera, Lepidoptera and Tenthredinidae larvae) and ‘Other’ (containing other orders and any unidentified invertebrates) and log ratios produced as Section 4.2.1. In R (Ihaka and Gentleman 1996) the invertebrate groups are bound into a single response variable using cbind and significance tested with a MANOVA. A ranking matrix was produced comparing the log-ratios of all group pairings within the diet to determine which groups were causing any significant differences. The t values required in the matrix were calculated from F values generated by an ANOVA test. Using ANOVA rather than t-tests allows any interaction between factors to be accounted for.

Standard invertebrate samples were also collected from the field using a sweep net and vacuum sampler (as described in Section 2.3) either the same day or within two days depending on weather. The proportion of each invertebrate group found in the field was compared with the proportion found in the chicks’ diet to determine any preferences for or avoidance of certain groups (Hill 1985). These proportions were normalised using arcsine then tested using paired t-tests. A comparison of the two sampling methods was analysed the same way. The number of invertebrates collected by the standard methods was compared by paired t-tests; the total number of individuals collected was tested as is and then again after the removal of any groups that were not found in the chicks’ diet in any samples collected. Paired t-tests were used here to remove any influence of date or habitat. The total number of invertebrates collected in the different habitats was compared using ANOVA or Student’s t-test on normalised data (taking the squared root) if the samples were of approximately equal size and Kruskal-Wallis or Mann-Whitney tests if sample sizes varied greatly.

5.2.2 Vegetation

Vegetation surveys were carried out over 2-3 days following the final field trial of each month as described in Section 2.4. GLMs were carried out to compare the habitats in terms of vegetative structure using the error structures in Table 5.3. Habitat,

73 month and year were used as explanatory variables in the GLMs and the models simplified step-wise to determine which factors affected each response variable. Correlations between the various vegetation measurements were tested using Pearson’s correlation test having first normalised the data as required (Table 5.3).

Table 5.3 Data used to assess vegetation structure. Type of data Function to normalise Error structure Height (cm) Normal None Gaussian Vegetation cover (%) Percentage Arcsine square-root Gaussian* Dicotyledons:monocotyledons Proportion Arcsine Gaussian* Line of sight (cm) Normal Reciprocal Gaussian* Tennis ball cover (1-4) Proportion Arcsine Binomial Number of chicks visible Proportion Arcsine Binomial *Normalise data then use Gaussian errors.

Canonical correspondence analysis (CCA) was used to test the effect of uncorrelated vegetative features together with Day, Year and Chick Age on chick diet in MVSP (v3.1). The prey items were considered at their lowest possible grouping although unidentified items were removed from the analysis. Since rare species are known to skew the results of correspondence analyses (Shaw 2003), any items occurring in fewer than three samples were removed and rare species were also down-weighted in the analysis. The variance inflation factor (VIF) was considered and any variable with a VIF over 20 was rejected, since a high VIF implies redundancy in that variable with respect to the others (Ter Braak 1986). The variables were also tested against the CCA case scores for axes one and two using Pearson’s product-moment correlation tests. A significant correlation indicates that variable is influencing chick diet.

5.3 Results

During the three years the average hatching rate was 49.8%; however, during 2008 hatching and survival rates were low due to an egg infection. Excluding 2008 from the results gives an average hatching rate of 57.5%. This is less than in wild broods (Robertson 1997) but seems on average with other hand-reared rates where eggs had been stored for a few days prior to incubation (Ipek et al. 2006; Ko żuszek et al. 2009). Average imprinting rates were 82.5% in 2007, 91.3% in 2008 and 87.9% in 2009. The 2008 rate is higher due to the inclusion of wild pheasant eggs. If only farm-bought eggs are considered the average imprinting rate over the three years was 86.4%.

74

5.3.1 Invertebrate sampling and chick preference

The sweep net collected significantly more individual invertebrates than the vacuum sampler (t = 2.19, P < 0.05). After the removal of groups not discovered in the chicks diet (Mollusca, Thysanoptera, Collembola, parasitic Acari, Phthiraptera and adult Lepidioptera) no significant difference was found between these sampling methods (t = -0.91, P = 0.37) (Figure 5.1).

140 * Vacuum sampler 120 (n=50) Sweep net (n=96) 100

80

60

40

20 Number of invertebrates ofNumberinvertebrates collected 0 Total Total (chick prey)

Figure 5.1 The number of invertebrates collected by different sampling methods (with standard errors). * indicates significance at α = 0.05.

Table 5.4 Comparing the proportion of different taxa collected in sweep net and vacuum samples t value Degrees of freedom P value Araneae -0.08 49 0.935 Hemiptera -4.78 49 <0.001 *** Larvae 1.77 49 0.083 Hymenoptera 0.58 49 0.566 Coleoptera 0.42 49 0.674 Other 4.27 49 <0.001 ***

Comparing the proportions of different invertebrate groups found in the diet of imprinted chicks with those found in sweep nets and vacuum samples taken in the same locations shows that although there are discrepancies between the latter two methods they always differ from the chick’s diet in the same direction (Figure 5.2). The vacuum sampler collected significantly more of the group ‘Other’ (Table 5.4) than the sweep net due to the large number of Diptera suction sampling collected. The sweep net collected significantly more Hemiptera than the vacuum sampler (Table 5.4). The only difference when considering chick preference lies in the group larvae where the sweep net samples are significantly lower than the chicks’ diet (t = 2.62, P < 0.05) whereas the vacuum samples are not (t = -1.55, P = 0.13) (Tables 5.5 and 5.6).

The other groups that occur at a greater frequency in the chicks’ diet than in the sweep net sample are the Hymenoptera and the Coleoptera (Table 5.5). The Araneae, Hemiptera and ‘Other’ all occur at higher proportions in the field than in the pheasant chicks’ diet (Table 5.5).

0.6 Vacuum *** (n=50) *** a Sweep 0.5 *** (n=96) Diet a a *** (n=96) 0.4 a

0.3 b

Proportion b b b 0.2 b b c *** * 0.1 a a c a ab b b 0 Araneae Hemiptera Larvae HymenopteraColeoptera Other

Figure 5.2 Comparing proportions of invertebrate orders found in the field by vacuum sampling and sweep netting with the proportions found in the diet of pheasant chicks (with standard errors). * indicates significance at α = 0.05, *** at α = 0.001, different letters denote significance.

Within orders the only significant preferred families are Formicidae (t = -7.67, P < 0.001) and Tenthredinidae (t = 2.61, P < 0.05) (comparing with sweep net and vacuum samples respectively) (Figure 5.3). These are also the only two cases when the proportions in the sweep and vacuum samples differ significantly (Table 5.4). The only significant avoidance is for other wasp families (comparing with sweep net samples). There appears to be an avoidance of Aphididae, but this trend is not significant.

Table 5.5 Comparing the proportion of different taxa found in the diet of pheasant chicks with those collected in sweep net samples t value Degrees of freedom P value Araneae -5.17 95 <0.001 *** Hemiptera -13.65 95 <0.001 *** Larvae 2.62 95 0.010 * Hymenoptera 5.76 95 <0.001 *** Coleoptera 9.31 95 <0.001 *** Other -6.69 95 <0.001 ***

Table 5.6 Comparing the proportion of different taxa found in the diet of pheasant chicks with those collected in vacuum samples t value Degrees of freedom P value Araneae 4.28 49 <0.001 *** Hemiptera 2.62 49 0.012 * Larvae -1.55 49 0.127 Hymenoptera -3.87 49 <0.001 *** Coleoptera -9.87 49 <0.001 *** Other 10.52 49 <0.001 ***

a a ***

b *** a

* b a b c c

Figure 5.3 Comparing proportions of invertebrate families found in the field by vacuum sampling and sweep netting with the proportions found in the diet of pheasant chicks (with standard errors). * indicates significance at α = 0.05, *** at α = 0.001, different letters denote significance.

5.3.2 Foraging in different commercial crops

Over the three years trials in 20 winter sown cereal, 12 spring sown cereal and 15 other crop habitats were conducted; the majority of these were in winter wheat since this was the most dominant crop in all three years (36.5%, 37.6% and 37.2% respectively). Fewer invertebrates were caught in the non-cereal crops (Figure 5.4) but the difference is significant only in the vacuum samples (H 2 = 13.96, P < 0.01) and not the sweep net samples (H 2 = 4.96, P = 0.08).

160 Winter sown cererals (n=20) 140 Spring sown cereals (n=12) 120 Other crops (n=15)

100

80

60

40

Number ofNumber invertebrates 20

0 Vacuum sampler Sweep net

Figure 5.4 Total number of invertebrates found in different crop types using two different sampling methods (with standard errors). ** indicates significance at α = 0.01, different letters denote significance.

Diet

Chicks foraging in winter and spring sown cereals ate a greater number and variety of invertebrates than chicks foraging in other crop types (Figure 5.5), although this difference is not significant for the total number of invertebrates consumed (F 2,46 = 2.75, P = 0.08). Significantly more invertebrate groups were consumed in winter cereals than non-cereal crops (F 2,46 = 5.38, P < 0.01). No significant difference was found in the composition of diet for chicks foraging in the different crop fields (F 10,76 = 1.12, Wilk’s Λ = 0.76, P = 0.36) (Figure 5.6). Month was the only factor found to significantly affect dietary composition (F 10,80 = 3.01, Wilk’s Λ = 0.53, P < 0.01).

78 250 Winter sown cereals (n=20)

200 Spring sown cereals (n=12

Other crops (n=15 150 Count 100 *

50 a ab b

0 Number of invertebrates Number of invertebrate Eaten groups eaten

Figure 5.5 The quantity and taxonomic diversity of invertebrate groups eaten by human- imprinted pheasant chicks foraging in crop fields (with standard errors). * indicates significance at α = 0.05, different letters denote significance.

1.00 0.00 0.00 0.01 Araneae 0.12 Hemiptera 0.90 0.21 0.16 0.04 Larvae 0.80 Hymenoptera 0.03 0.04 Coleoptera 0.19 0.70 0.22 Other 0.24 0.60

0.50

0.40 Proportion in diet Proportion 0.60 0.54 0.30 0.46

0.20

0.10

0.04 0.06 0.04 0.00 Winter sown Spring sown Other crops cereals cereals

Figure 5.6 Dietary composition of human-imprinted pheasant chicks foraging in crop fields.

Crop type had no significant effect within the Hemiptera (F 4,74 = 0.59, Wilk’s Λ =

0.94, P = 0.67) or Hymenoptera (F 4,76 = 2.15, Wilk’s Λ = 0.81, P = 0.08) groups. There was a significant effect of the Month:Year interaction on the composition of

Hymenoptera families consumed (F 2,38 = 4.24, Wilk’s Λ = 0.82, P < 0.05), although the high value of Wilk’s lambda indicates a weak relationship. Crop type affected the proportions of the different larval groups consumed (F 4,32 = 7.47, Wilk’s Λ = 0.27, P

< 0.001) (Figure 5.7), but this effect varied as a function of year (Crop:Year, F4,32 =

5.46, Wilk’s Λ = 0.35, P < 0.01) and chick age (Crop:Age, F4,32 = 4.17, Wilk’s Λ = 0.43, P < 0.01).

1.00 Coleoptera 0.17 0.90 Lepidoptera Tenthredinidae 0.80

0.70 0.57 0.64 0.60

0.50 0.67

0.40 0.00

Propportion Propportion diet in 0.30 0.20 0.20 0.43

0.10 0.16 0.17 0.00 Winter sown Spring sown Other crops cereal cereal

Figure 5.7 Proportions of larvae types eaten by pheasant chicks foraging in different crop fields.

Ranking matrices (Table 5.7) comparing the three crop types pairwise showed that the difference lay in the absence of Lepidoptera larvae and the high proportion of Tenthredinidae larvae in the diet of chicks foraging in spring sown cereals; also in the high proportion of Lepidoptera and low proportion of Coleoptera larvae consumed in the other crops. Splitting the data by year showed that the proportion of Lepidoptera larvae in the diet declined over the three years, whilst the proportion of Tenthredinidae increased in the cereal crops. Coleoptera larvae were more prolific in 2008 than in either 2007 or 2009 (Figure 5.8). Although this effect may be due to the

80 significant effect of year (F 2,16 = 8.75, Wilk’s Λ = 0.48, P < 0.01) and the small sample sizes for some habitats in some years.

Table 5.7 Ranking matrices of the relative differences in the larval component of the diet of pheasant chicks foraging in different cereals: (a) spring- and winter-sown cereals. Within the matrix (+) indicated a row taxa is found at greater proportions in spring cereals, (-) means the opposite. Numerator Denominator Rank Tenthredinidae Coleoptera Lepidoptera Tenthredinidae + +++ 2 Coleoptera - + 1 Lepidoptera --- - 0

(b) spring-sown cereals and other crops. Within the matrix (+) indicated a row taxa is found at greater proportions in other crops, (-) means the opposite. Numerator Denominator Rank Lepidoptera Tenthredinidae Coleoptera Lepidoptera +++ +++ 2 Tenthredinidae --- + 1 Coleoptera --- - 0

(c) winter-sown cereals and other crops. Within the matrix (+) indicated a row taxa is found at greater proportions in winter cereals, (-) means the opposite. Numerator Denominator Rank Coleoptera Tenthredinidae Lepidoptera Coleoptera +++ +++ 2 Tenthredinidae --- + 1 Lepidoptera --- - 0 Triple sign indicates significance at α = 0.05.

The interaction between chick age and crop type was not tested statistically due to the small sample size of some age categories, five of which are from a single trial brood.

Within the larval groups both month (F 4,32 = 8.38, Wilk’s Λ = 0.24, P < 0.001) and the

Month:Year interaction (F 2,16 = 16.90, Wilk’s Λ = 0.32, P < 0.001) were also significant. Crop type and month had the strongest relationships with dietary composition shown by their low Wilk’s lambda values.

81

Figure 5.8 The interaction between year and crop type on the proportion of different larval groups consumed by pheasant chicks foraging in spring and winter sown cereals and in non- cereal (other) crops. Dark grey: Coleoptera; white: Lepidoptera; light grey: Tenthredinidae.

Vegetation

Winter sown cereal is taller than non-cereal crops (t 42 = 2.52, P < 0.05) (Figure 5.9) but provides less visual obstruction from above (t 44 = -2.60, P < 0.05) (Figure 5.10) and a greater proportion of chicks were visible whilst foraging in winter sown cereals compared to non-cereal crops (t 31 = -2.34, P < 0.05). Spring sown cereals have a greater percentage cover of vegetation than non-cereal crops (t 44 = 2.13, P < 0.05) (Figure 5.9), although this did not provide a greater visual obstruction score from above (t 44 = -1.30, P = 0.20) (Figure 5.10). Spring sown cereals do provide greater visual obstruction from the side compared to non-cereal crops (t 44 = 3.33, P < 0.01) (Figure 5.10). Spring sown cereals also had the lowest line of sight distance (Figure

5.9) but the effect of this is confounded by the significant interaction with month (t 41 = -2.25, P < 0.05). All other comparisons between crop types were not significant. The proportion of dicotyledons was not tested since values were nearing either zero or 100 depending on the crop type

82 100 100 * Winter Cereal * a 90 a 90 (n=20) ab b Spring Cereal 80 b 80 (n=12) b 70 70 Other crops (n=15) 60 ** 60 a 50 50 cm

Percentage 40 40

30 30 b 20 b 20

10 10 N/A 0 0 Vegetation (% Dicotyledrons Chick line of Vegetation cover) (% vegetation) sight (cm) height (cm)

Figure 5.9 Vegetative structure of commercial crops (with standard errors). * indicates significance at α = 0.05, ** at α = 0.01, different letters denote significance.

4 a ab * Winter Cereal 3.5 (n=20) * b 3 a Spring Cereal ab (n=12) 2.5 b Other crops 2 (n=15) 1.5 1

Visual obstructionVisual score 0.5 0 Above Side

Figure 5.10 Visual obstruction scores when viewing a chick sized object in different commercial crops (with standard errors). * indicates significance at α = 0.05, ** at α = 0.01, different letters denote significance.

5.3.3 The benefits of non-crop areas to pheasant chicks foraging in arable farmland

Over the three years 47 field trials were conducted in commercial crop fields and 49 field trials in non-crop areas. These non-cropped areas included both long term set- aside and sown game crops; in this section they are referred to as simply set-aside. In 2008 and 2009 the non-cropped areas decreased in line with EU changes in set-aside regulations from 11.7% in 2007 to 8.2% in 2008 and 8.1% in 2009. Significantly more invertebrates were found in the non-cropped areas using data from both the sweep net (t 93 = -6.55, P < 0.001) and vacuum sampler (W = 736.0, P < 0.01) (Figure 5.11).

250 *** Crop (n=47) 200 ** Set aside (n=49)

150

100

50 Number ofNumberinvertebrates

0 Vacuum sampler Sweep net

Figure 5.11 Total number of invertebrates found in cropped and non-cropped areas using two different sampling methods (with standard errors). ** indicates significance at α = 0.01, *** at α = 0.001.

Diet

No significant difference was found in the number of invertebrate prey consumed (t 78

= 1.02, P = 0.31) nor the diversity of invertebrate prey taken (t 74 = 0.64, P = 0.53) by pheasant chicks foraging in cropped and non-cropped arable areas (Figure 5.12). A significant difference was found in the composition of prey types taken (F 5,87 = 3.81, Wilk’s Λ = 0.82, P < 0.01) (Figure 5.13). Proportionally more Hymenoptera are consumed in the non-crop areas and more Hemiptera consumed in the crop fields

(Table 5.8). Month (F 5,87 = 3.94, Wilk’s Λ = 0.67, P < 0.001) and year (F 5,87 = 2.63, Wilk’s Λ = 0.87, P < 0.05) also significantly affect what invertebrates are consumed but no interactions between these terms are significant.

180 Crop 160 (n=47) Set aside 140 (n=49) 120

100

Count 80

60

40

20

0 Number of invertebrates Number of invertebrate consumed groups consumed

Figure 5.12 The quantity and taxonomic diversity of invertebrate groups eaten by human- imprinted pheasant chicks foraging in crop and non-crop areas (with standard errors). * indicates significance at α = 0.05, ** at α = 0.01, *** at α = 0.001.

1.0 0.010.06 0.01 Araneae 0.9 0.16 Hemiptera 0.03 Larvae 0.04 0.8 Hymenoptera Coleoptera 0.7 0.21 0.42 Other 0.6

0.5

0.4 Proportions diet in 0.3 0.55 0.43 0.2

0.1

0.04 0.04 0.0 Crop Set aside

Figure 5.13 Dietary composition of human-imprinted pheasant chicks foraging in crop and non-crop areas.

85 Table 5.8 Ranking matrix of the relative differences between the diets of human-imprinted pheasant chicks foraging in crop and non-crop areas. Within the matrix (+) indicated a row taxa is found at greater proportions in crop fields, (-) means the opposite, triple sign indicates significance at α = 0.05. Numerator Denominator Rank Hemiptera Larvae Coleoptera Araneae Other Hymenoptera Hemiptera + +++ +++ +++ +++ 5 Larvae - + + + +++ 4 Coleoptera --- - + + +++ 3 Araneae --- - - + +++ 2 Other ------+ 1 Hymenoptera ------0

Within the larvae group there is no significant effect of habitat type (F 2,47 = 2.55,

Wilk’s Λ = 0.90, P = 0.09) but the interaction of habitat and year was significant (F 2,47 = 7.08, Wilk’s Λ = 0.77, P < 0.01). Analysing each year separately (Table 5.9) found that the effect of habitat was only significant in an interaction with chick age in 2007. In 2009 only two non-crop areas were surveyed so statistical tests could not be run, however in the crop fields all larvae consumed were Tenthredinidae and in the non- crop areas only Lepidoptera larvae were eaten. Month (F 4,94 = 4.06, Wilk’s Λ = 0.73,

P < 0.01), year (F 2,47 = 6.08, Wilk’s Λ = 0.80, P < 0.01) and the Month:Year interaction (F 2,47 = 5.09, Wilk’s Λ = 0.82, P < 0.01) also significantly affected the composition of larvae in the diet.

Table 5.9 Compositional analysis results comparing the larval component of the diet of pheasant chicks foraging in crop and non-crop areas in different years.

Year Factor Wilk’s Λ F value Degrees of freedom P value 2007 Habitat 0.946 0.54 (2,19) 0.591 Month 0.776 1.28 (4,38) 0.294 Age 0.935 0.66 (2,19) 0.527 Habitat:Age 0.700 4.07 (2,19) 0.034 * 2008 Habitat 0.933 0.64 (2,18) 0.538 Month 0.948 0.49 (2,18) 0.613 Age 0.856 1.28 (2,18) 0.303 2009 (Sample size too small. Crop: all Tenthredinidae; Non-crop: all Lepidoptera.)

Within the Hemiptera habitat type had a significant effect on dietary composition

(F 2,64 = 9.28, Wilk’s Λ = 0.78, P < 0.001). A significantly higher proportion of Aphididae were consumed in the crop fields and a significantly higher proportion of Heteroptera consumed in the non-crop areas (Figure 5.15) (Table 5.5). No other factors were significant on their own but the Month:Year interaction (F 2,64 = 4.24,

Wilk’s Λ = 0.88, P < 0.05) and the Month:Chick Age interaction (F 4,128 = 2.98, Wilk’s Λ = 0.84, P < 0.05) were both significant.

86

Habitat type also has a significant effect on the Hymenoptera component of chick diet

(F 2,87 = 4.928, Wilk’s Λ = 0.898, P < 0.01). Formicidae made up a greater proportion of the diet of chicks foraging in non-crop areas than in the crop fields (Figure 5.16) (Table 5.6). The interaction between habitat and year was significant within the

Hymenoptera (F 2,87 = 7.188, Wilk’s Λ = 0.558, P < 0.01) and the lower value of Wilk’s lambda means the interaction had a stronger effect than the habitat type alone. The proportion of Formicidae and other wasps seems to fluctuate in antiphase between the years. The dominant group in each habitat type also fluctuates. The proportion of Tenthredinidae seems to decline from low to absent in the set-aside areas but increases in the crop fields in 2009 (Figure 5.17). Year alone is not a significant predictor of diet composition of hymenopteran groups (F 2,87 = 1.390,

Wilk’s Λ = 0.969, P = 0.255) but month (F 4,174 = 2.955, Wilk’s Λ = 0.877, P < 0.05) and the Month:Year (F 2,87 = 3.631, Wilk’s Λ = 0.923, P < 0.05) interaction are significant.

1.00 0.08 Heteroptera 0.90 OtherHomoptera 0.80 0.21 0.45 Aphid 0.70

0.60

0.50 0.17 0.40

Proportion Proportion diet in 0.70 0.30

0.20 0.39

0.10

0.00 Crop Set aside

Figure 5.14 Composition of Hemiptera in the diet of pheasant chicks foraging in crop and non-crop areas.

87 Table 5.10 Ranking matrix of the relative differences in the Hemiptera component of the diet of pheasant chicks foraging in crop and non-crop areas. Within the matrix (+) indicated a row taxa is found at greater proportions in crop fields, (-) means the opposite, triple sign indicates significance at α = 0.05. Numerator Denominator Rank Aphid Other Homoptera Heteroptera Aphid + +++ 2 Other Homoptera - +++ 1 Heteroptera ------0

1.00 0.07 0.03 0.90

0.80 Tenthredinidae Wasp 0.50 0.70 Formicidae

0.60 0.66

0.50

0.40 Proportion in diet in Proportion 0.30 0.46 0.20 0.27 0.10

0.00 Crop Set aside

Figure 5.15 Composition of Hymenoptera in the diet of pheasant chicks foraging in crop and non-crop areas.

Table 5.11 Ranking matrix of the relative differences in the Hymenoptera component of the diet of pheasant chicks foraging in crop and non-crop areas. Within the matrix (+) indicated a row taxa is found at greater proportions in crop fields, (-) means the opposite, triple sign indicates significance at α = 0.05. Numerator Denominator Rank Other wasps Tenthredinidae Formicidae Other wasps + +++ 2 Tenthredinidae - +++ 1 Formicidae ------0

88

Figure 5.16 Composition of Hymenoptera in the diet of pheasant chicks foraging in crop and non-crop areas over 2007 - 2009. Dark grey: Tenthredinidae; white: other wasps; light grey: Formicidae.

Vegetation

Vegetation in non-crop areas contains on average a greater proportion of dicotyledons

(t 92 = 2.86, P < 0.01) and provides greater cover than commercial crops in terms of percentage cover (t 91 = 4.76, P < 0.001) (Figure 5.18). Visual obstruction is greater from the side in set-aside but this is confounded by an interaction with year (t 90 = - 2.55, P < 0.05). Although visual obstruction from above is greater in non-crop areas

(Figure 5.19) this difference is not significant (t91 = 1.46, P = 0.15). Chicks have a longer line of sight (t 92 = 5.02, P < 0.001) in commercial crops (Figure 5.18). The proportion of chicks visible in the field is greater in non-crop areas during May, but not during June (interaction: t 45 = 2.16, P < 0.05), possibly in part due to the limitation in crop habitats available during May.

89 90 90 *** Crop 80 80 (n=47) *** 70 70 Set aside (n=49) 60 60

50 50

** cm 40 40 Percentage 30 30

20 20

10 10

0 0 Vegetation Dicotyledrons Chick line of Vegetation cover (%) (% vegetation) sight (cm) height (cm)

Figure 5.17 Vegetative structure of commercial crops and non-crop areas (with standard errors). * indicates significance at α = 0.05, ** at α = 0.01, *** at α = 0.001.

4 Crop 3.5 * (n=47) 3 Set aside (n=49) 2.5 2 1.5 1

Visual Visual obstruction score 0.5 0 Above Side

Figure 5.18 Visual obstruction scores when viewing a chick sized object in commercial crops and non-crop areas (with standard errors). * indicates significance at α = 0.05, ** at α = 0.01, *** at α = 0.001.

Multivariate statistics

Significant correlations are found between most of the vegetative measures. The proportion of dicotyledons correlates with vegetation height (r = -0.353, P < 0.001), percent cover (r = 0.256, P = 0.011) and visual obstruction scores from above (r = 0.461, P < 0.001) and the side (r = 0.230, P < 0.001). Percent cover also correlates with the visual obstruction scores from both above (r = 0.462, P < 0.001) and the side (r = 0.517, P < 0.001) and also with chick line of sight (r = 0.558, P < 0.001). Visual obstruction scores from above correlate with those from the side (r = 0.388, P < 0.001). No other pairings correlate. The number of chicks visible does not correlate with any other measures but this was only measured in 2008 and 2009 and so has been excluded from the multivariate statistics.

Canonical correspondence analysis (CCA) using vegetation cover, vegetation height, date, year and chick age shows that date, year and percentage vegetation cover explain much of the variation, shown by their long arrow lengths (Figure 5.20). Axis one has a high eigenvalue of 0.47 and explains 10.9% of the variation in the data, axis two has a lower eigenvalue of 0.19 and explains only 4.3% of the variation. Date corresponds positively and year negatively with axis one and vegetation height corresponds with axis two. All the factors correlate to axes one or two or both with the exception of chick age, which does not correlate to either axis and so is the only factor included that is not significantly affecting chick diet. There is no clear separation of habitat type by diet although some trends appear (Figure 5.20). The winter cereals are only available at early dates, mostly before the sown set-aside and other crops have appeared. The cereal crops form a tight cluster at the top left of the plot whilst the other crops and sown set-aside areas all show great variation in both the insect prey they contain and their vegetative features. Long term set-aside falls low on axis two but has a wide spread along axis one with a lot of overlap with sown set-aside and non-cereal crops.

91

Figure 5.19 CCA biplot of habitats by chick diet. The environmental variables are: Day , date; Year, year; Age, chick age; Cover , percent vegetation cover; Height, vegetation height. Vector scaling 4.09.

A similar clustering and overlapping pattern is found when CCA is performed using chick line of sight and the proportion of dicotyledons instead of vegetation height and percent cover. Here axis one has an eigenvalue of 0.47 explaining 10.9% of the variation and axi s two has an eigenvalue of 0.21 and explains 4.9% of the variation in the data. The VIFs and Pearson’s correlation coefficients of both sets are very similar but since more of the variation is explained by using vegetation height and cover only that plot is shown.

5.3.4 Comparison of long-term set-aside and game crop schemes

Twenty-two field trials were conducted in long term set-aside or other areas of naturally regenerated weeds and grasses over the three years. Twenty -seven trials in rotational set-aside and sown game or cover crops were also carried out , consisting of 12 in sorghum game crop, 12 in trial seed mixes and three in alfa lfa. No significant difference was found in the number of insects caught in the different non -crop habitats either using the vacuum sampler (W = 50.0, n 1 = 6, n 2 = 9, P = 0.86) or sweep net (H 6 = 4.97, P = 0.55) (Figure 5.21 ). 300 Game crop 250 (n=27) Grass 200 (n=22)

150

100

50 Number ofNumber invertebrates

0 Vacuum sampler Sweep net

Figure 5.20 Total number of invertebrates found in long term set-aside (Grass) and game crop areas using two different sampling methods (with standard errors).

Diet

Pheasant chicks ate more invertebrates in the long term set-aside than in the sown game crop areas (t 34 = -3.55, P < 0.01) but the same number of invertebrate groups (t 40 = -1.22, P = 0.23) (Figure 5.22).

180 ** Game crop 160 (n=27) Grass 140 (n=22) 120 100 80 Count 60 40 20 0 Number of Number of invertebrates invertebrate groups consumed consumed

Figure 5.21 The quantity and taxonomic diversity of invertebrate groups eaten by human- imprinted pheasant chicks foraging in long term set-aside (grass) and sown game crops (with standard errors). ** indicates significance at α = 0.01.

There is a significant difference in the dietary composition of pheasant chicks foraging on long term set-aside and game crops (F 5,41 = 6.57, Wilk’s Λ = 0.56, P < 0.001). The ranking matrix (Table 5.7) indicates this difference is due to the high proportion of Hymenoptera consumed in the long term set-aside areas (Figure 5.23).

Month also significantly affected the composition of pheasant diet (F 10,82 = 2.21, Wilk’s Λ = 0.62, P < 0.05).

1.00 0.01 0.07 0.05 0.00 Araneae 0.90 0.04 0.02 Hemiptera Larvae 0.80 Hymenoptera 0.27 Coleoptera 0.70 Other 0.61 0.60

0.50

0.40 Proportion in diet 0.55 0.30

0.20 0.29

0.10 0.06 0.00 0.03 Game crop Grass

Figure 5.22 Dietary composition of pheasant chicks foraging in game crop and long term grassy set-aside.

Table 5.12 Ranking matrix of the relative differences between the diets of pheasant chicks foraging in long term set-aside and game crop areas. Within the matrix (+) indicated a row taxa is found at greater proportions in game crop, (-) means the opposite, triple sign indicates significance at α = 0.05. Numerator Denominator Rank Other Araneae Hemiptera Coleoptera Larvae Hymenoptera Other + + + + +++ 5 Araneae - + + + +++ 4 Hemiptera - - + + +++ 3 Coleoptera - - - + +++ 2 Larvae - - - - + 1 Hymenoptera ------0

Habitat significantly affects the proportion of Hemiptera groups consumed by the chicks (F 2,64 = 9.28, Wilk’s Λ = 0.78, P < 0.001), with more Homoptera consumed in the game crop and more Heteroptera in the grass areas (Figure 5.24) (Table 5.8).

Whilst none are significant on their own, the Month:Year (F 2,64 = 4.24, Wilk’s Λ =

94 0.88, P < 0.05) and Month:Chick Age (F 4,128 = 2.98, Wilk’s Λ = 0.84, P < 0.05) interactions both significantly affect the Hemiptera components of chick diet.

1 Heteroptera 0.9 Other Homoptera 0.8 0.44 0.45 Aphid 0.7

0.6

0.5 0.15 0.19 0.4 Proportion Proportion in diet

0.3

0.2 0.41 0.35

0.1

0 Game crop Grass

Figure 5.23 Composition of Hemiptera in the diet of pheasant chicks foraging in game crop and long term set-aside areas.

Table 5.13 Ranking matrix of the relative differences in the Hemiptera component of the diet of pheasant chicks foraging in game crop and long term set-aside areas. Within the matrix (+) indicated a row taxa is found at greater proportions in game crop, (-) means the opposite, triple sign indicates significance at α = 0.05. Numerator Denominator Rank Heteroptera Aphid Other Homoptera Heteroptera + + 2 Aphid - + 1 Other Homoptera - - 0

Within the Hymenoptera component of the diet habitat has a significant effect (F 2,42 =

6.49, Wilk’s Λ = 0.76, P < 0.01), as do year (F 2,44 = 9.79, Wilk’s Λ = 0.69, P < 0.001) and chick age (F 2,44 = 4.78, Wilk’s Λ = 0.82, P < 0.05). The difference due to habitat is because there is a greater proportion of other wasps eaten by chicks foraging in game crop areas (Figure 5.25) (Table 5.9).

95

Figure 5.24 Composition of Hymenoptera in the diet of pheasant chicks foraging in game crop and long term set-aside areas .

Table 5.14 Ranking matrix of the relative differences in the Hymenoptera component of the diet of pheasant chicks foraging in game crop and long term set-aside areas. Within the matrix (+) indicated a row taxa is found at greater proportions in game crop, ( -) means the opposite, triple sign indicates significance at α = 0.05. Numerator Denominator Rank Other wasps Tenthredinidae Formicidae Other wasps +++ +++ 2 Tenthredinidae --- + 1 Formicidae --- - 0

Within the larval groups there was no significant affect of habitat on composition

(F 2,22 = 0. 19, Wilk’s Λ = 0.98, P = 0.83 ) but there was a significant affect of year

(F 2,22 = 4.25, Wilk’s Λ = 0.72, P < 0.05).

Vegetation

There was no significant difference in height (t 47 = -0.83, P = 0.41) or chick line of sight distance (t 45 = 0.73, P = 0.47 ) in the different types of set-aside (Figure 5.2 6). Sown game crops he ld a greater proportion of dicotyledons than the grass areas and percentage vegetation cover wa s greater in sown game crop than grass areas (Figure 5.26) but in both cases there is a significant interaction with month (percent cover: t 41

= -3.25, P < 0.01; dicotyledons: t 44 = 2.39, P < 0.05). There was no difference in visual obstruction when viewed from the side (t 44 = -1.50, P = 0.14) but the game crop provided greater cover from above (t 44 = -0.07, P < 0.001) (Figure 5.27). There was no significant difference in the number of foraging chicks visible in each habitat during the field trials (t 12 = 1.77, P = 0.10).

100 100 *** *** Grass 90 90 (n=22) Game crop 80 80 (n=27) 70 70 60 60 50 50 cm 40 40 Percentage 30 30 20 20 10 10 0 0 Vegetation (% Dicotyledrons Chick line of Vegetation cover) (% vegetation) sight (cm) height (cm)

Figure 5.25 Vegetative structure of sown game crop and long term grassy set-aside (with standard errors). *** indicates significance at α = 0.001.

4 *** Grass (n=22) 3.5 3 Game crop (n=27) 2.5 2 1.5 1

Visual obstructionscore Visual 0.5 0 Above Side

Figure 5.26 Visual obstruction scores when viewing a chick sized object in different set-aside habitats (with standard errors). *** indicates significance at α = 0.001.

Multivariate analysis

CCA was run using the proportion of dicotyledons, chick line of sight, date, year and chick age. Axis one has a high eigenvalue of 0.5 8 and explains 15.2% of the variation in the data, ax is two has an eigenvalue of 0.31 and explains 8.1% of the variation. Year correlates positively, and date negatively , with axis one and the proportion of dicotyledons correlates positively with axis two. Chick age and chick line of sight do not correlate with either axes and so are not significantly influencing chick diet.

Th e alfalfa areas are the only ones to separate from the other habitat types and appear to be influenced by their high proportion of dicotyledons (Figure 5.28). The seed mixes overlap slightly with the long term grassy set-aside areas with the latter falling lower down axis two. Seed mix one separates out slightly from the other seed mixes by its lower values on both axes. Sorghum plots overlap the seed mixes and the long term set-aside with more intermediate values on axis two.

Figure 5.27 CCA biplot of non-crop habitats by chick diet. The environmental variables are: Day, date; Year, year; Age, chick age; Dicots , proportion of dicotyledons; LoS, chick line of sight. Vector scaling 3.75.

Running a CCA using vegetation height and percent cover instead of chick line of sight and proportion of dicotyledons gave a similar scatter plot but axes one and two only explained 19.9% of the variation between them compared to 23.3% in the previous analysis.

5.4 Discussion

5.4.1 Insect sampling methods

These results support previous studies of insects in farmland in noting different counts of invertebrates with different sampling techniques (Costa and Corseuil 1979; Standen 2000; Randel et al. 2006), with more invertebrates being collected by the sweep net than the vacuum sampler. Certain invertebrate groups collected in the field were not seen in the chick faeces; this could be due to them occurring out of the reach of chicks (eg. adult Lepidioptera), being too small to be of interest to the chicks or to survive digestion (eg. Collembola, Thysanoptera, parasitic Acari, Phthiraptera), or because chicks seemed uninterested in them (eg Mollusca). Once these groups have been removed this study finds no difference in the total number of potential chick prey items collected by the two techniques but proportionally more Diptera and Formicidae and fewer Hemiptera and Tenthredinidae are collected by vacuum sampling than by sweep netting. This highlights the different niches sampled by the two techniques; the vacuum sampler is best at collecting small flying insects (flies and small wasps) whilst the sweep net is better at collecting groups that cling on to the vegetation (bugs and sawfly larvae). Pheasant chicks most commonly feed by picking prey items off the vegetation or ground since flying insects tend to remain out of reach (personal observation). In the areas used in this study more insects were observed on vegetation than on bare ground; those on the ground were predominately larger beetles, which are less likely to be eaten by the young chicks due to their size. From this study it would appear that the sweep net is an appropriate tool for measuring insect availability to foraging chicks, especially in low vegetation, when held low to the ground.

99 5.4.2 Preferred prey items

By comparing the proportion of invertebrate groups in these field samples to the proportions found in the diet of pheasant chicks foraging in the same habitats, it is possible to determine which invertebrates are of most dietary importance to the chicks. Chicks tend to eat greater proportions of Hymenoptera, Coleoptera and insect larvae and fewer Hemiptera, Aranae and ‘Others’ than are available. Within the order Hymenoptera, Formicidae and Tenthredinidae are eaten in greater proportion than available whilst other wasp families appear to be avoided. No other families appear to be significantly preferred or avoided, although there is a trend to avoid Aphididae. This would tie in with previous studies that have shown aphids to be of low nutritional value (Borg and Toft 1999; Toft 2005). These findings are consistent with the chick food index for grey partridge (Potts and Aebischer 1991), which finds that small ground beetles (Carabidae) and caterpillars (Lepidoptera and Tethredinidae larvae) are of more importance in the chicks’ diet than certain Hemiptera groups (Miridae, Cicadellidae, Aphididae). Hill (1985) also found ground beetle and Tenthredinidae larvae to be preferred by pheasant chicks foraging in similar farmland habitats. Coleopteran families, Formicidae, Tenthredinidae, Hemiptera (including Aphididae) and Diptera are important prey items for many different species of farmland birds (Wilson 1966; Johansson and Blomqvist 1996; Poulsen et al. 1998; Wilson et al. 1999; Moreby and Stoate 2001; Dyrcz and Flinks 2003; Holland et al. 2006). In contrast a study of the grey partridge in eastern UK found that chick survival was negatively affected by a high proportion of Formicidae in their diet (Browne et al. 2006). Interestingly the same study found that in the laboratory both Formicidae and Coleoptera supplements led to increased growth rate implying that both groups have similar nutritional benefits.

Spiders have a higher protein content (at 55-60%) than adult Coleoptera (50%), whilst various larvae (Lepidoptera, Coleoptera and Symphyta) have a relatively low protein content (38-47%) (Cross 1966; Ramsay and Houston 2003). In spite of this spiders were seldom consumed, possibly due to orb weavers being mostly found higher in the vegetation whilst ground-dwelling spiders can move very quickly. All these invertebrate groups are similar in the essential amino acids they contain (Ramsay and Houston 2003). These larvae do contain proportionally more fat (16-31%) than other

100 invertebrate groups including adult Coleoptera and Hymenoptera (6-8%) (Cross 1966). The high abundance of Coleoptera probably outweighs their lower nutritional content making them an important dietary component. The same is probably true for Aphididae which is an important group (Holland et al. 2006) despite their low nutritional value (Borg and Toft 1999; Toft 2005) due to their high abundance in crop fields. Feeding studies of marine mesograzers found that a lower quality diet cannot replace a high quality diet despite compensatory feeding (Cruz-Rivera and Hay 2000); however, studies of grey partridge chicks found that even low quality prey items such as aphids can be beneficial in low proportions as part of a mixed diet (Borg and Toft 1999; Borg and Toft 2000).

This method of comparing diet and field samples includes influences due to both chick preference and how easily chicks can find and capture the different prey items. Some potential prey items may be avoided due to their size or colour; aposematic colouration is common in insects and predators often avoid these red insects (Roper 1990; Mastrota and Mench 1995; Poulsen et al. 1998; Gamberale-Stille and Tullberg 2001; Moreby et al. 2006). Other insects are camouflaged (de Ruiter 1952; Heinrich 1979; Chinery 1993; Noor et al. 2008) and so may be difficult for the chicks to detect unless they move. Some prey items are very quick moving and may run, jump or fly (Chinery 1993) out of the chicks’ reach. Due to their size pheasant chicks are only able to access those invertebrates that are found on the ground or in the lower levels of vegetation; this means many insects that fly or live only at the top of plants are unavailable to them.

5.4.2 Beneficial farmland habitats

Whilst no difference in dietary composition was found between different crop types, chicks foraging in cereal crops appear to eat a greater diversity of insects and more insects (although not significantly more). The vacuum sampling results indicate that this trend is probably due to more invertebrates being found in the cereal crops rather than any difference in foraging strategy caused by vegetative differences. Spring cereal appears to provide better cover for foraging chicks than non-cereal crops, although chicks are more hidden by these non-cereal crops than by winter sown cereals. Spring sowing of cereals is a farming technique that has declined as winter

101 sown strains became widely available (Ewald and Aebischer 2000). The switch from spring to winter sowing is detrimental to many farmland bird species as it removes the stubble fields that provide an essential over-winter food source (Newton 2004; Winspear and Davies 2005). The structure of spring cereal has also been shown to be beneficial to ground nesting and foraging birds as the later sowing keeps the crop more accessible to the birds (Odderskær et al. 1997; Wilson et al. 2001; Whittingham and Evans 2004).

Non-crop areas such as set-aside land, uncultivated field margins, flower strips, conservation headlands and beetle banks have been suggested as techniques to improve farmland biodiversity. Previous studies have discovered that agri- environmental schemes such as these can increase invertebrate biodiversity (Sotherton and Robertson 1990; Kromp and Steinberger 1992; Kromp 1999; Meek et al. 2002; Carvell et al. 2007; Cole et al. 2007; Smith et al. 2008a; Smith et al. 2008b; Woodcock et al. 2008), which in turn can benefit insectivorous birds and mammals (Hill and Robertson 1988; Kubišta 1990; Poulsen et al. 1998; Kaiser et al. 2006; MacDonald et al. 2007). Results vary greatly with different schemes, locations and scale (Sotherton 1998; Purtauf et al. 2005; Tscharntke et al. 2005; Marshall et al. 2006; MacDonald et al. 2007; Wrbka et al. 2008). Different taxa often show different responses: invertebrates and plants appear to benefit most from AESs whilst many bird species show no positive results (Klein and Sutherland 2003; Klein et al. 2006; Cole et al. 2007). This may be due to the high mobility of birds allowing them to utilise a wide range of areas. Targeted AESs are more likely to benefit the targeted groups than general options, however what is advantageous for one species may be detrimental to others (Klein and Sutherland 2003; Klein et al. 2006; Butler et al. 2007; Wilson et al. 2007). This study found no significant difference in the number of invertebrates consumed nor in the diversity of invertebrate groups consumed by pheasant chicks foraging in cropped and non-cropped areas, but there was a significant difference in dietary composition. Proportionally more Hymenoptera, especially Formicidae, were consumed by pheasants foraging in the non-crop areas and more Hemiptera, in particular Aphididae, by those in the crop fields. Since Hymenoptera and Formicidae are prey items preferred by chicks and Hemiptera and Aphididae are prey they tend to avoid it appears that non-crop areas provide a better foraging habitat. The multivariate biplot shows that the diet of chicks foraging in non-

102 cereal crops and sown game crops are more varied than those foraging in either cereals or naturally regenerated set-aside. The diets of chicks foraging in winter and spring sown cereals are composed of the same assemblage of prey types and this differs slightly from that of chicks foraging in naturally regenerated set-aside.

Once it is determined that non-cropped areas are of value to foraging chicks the question remains: which non-cropped habitats provide the most benefits? This study found no difference in the number of invertebrates in the different set-aside habitats, but the chicks ate more in the long term set-aside areas than the sown areas. This implies that the foraging structure of the long term, naturally regenerated areas (predominately grasses) may provide an easier foraging habitat for the chicks. The sown areas tend to be taller and denser than the naturally regenerated areas, which may hinder chick movement. Very dense vegetation can be a danger to young chicks as it retains water after rain and can cause the chicks to become chilled (Robertson 1997). Since game chicks cannot thermoregulate completely until at least 9 - 14 days old (Offerdahl and Fivizzani 1987; Gdowska et al. 1993; Pis 2002), chilling can quickly lead to hypothermia. The ideal habitat for chick foraging is one with a high level of cover from predators yet fairly open at ground level. It is unclear from this, and previous studies, what the optimum vegetation cover is to combine shelter from predators with ease of movement. It may be that no such optimum occurs and hen pheasants move their chicks between different habitats to take advantage of each depending on the weather, perceived predation risk and the energy requirements of her brood (Real and Caraco 1986; McNamara and Houston 1992; Suhonen 1993; Olsson et al. 2002). Bad weather will reduce chick foraging time since they cannot thermoregulate and require brooding from their mother (Gdowska et al. 1993; Panek 1997; Robertson 1997). A more heterogeneous environment will be of greater value since it will combine all features required for safe and successful foraging. Heterogeneity is likely to be higher in areas that are left to regenerate naturally for several years than in areas which are ploughed and re-sown annually.

The diet of chicks foraging in the different set-aside types varies significantly with more of the preferred Hymenoptera being consumed in the long term set-aside areas. The assemblages of prey consumed in the four seed mixes overlap greatly with the assemblage consumed in the sorghum; the only sown habitat that does not fall within

103 this grouping is the alfalfa, but only a few alfalfa areas were sampled. Naturally regenerated set-aside has a slight overlap with the sown set-aside and is characterised by its low proportion of dicotyledons. The diets of chicks foraging in both the sown areas and the naturally regenerated areas contain a high proportion of the prey groups the chicks prefer (86% and 92 % respectively). This provides some support for the hypothesis that set-aside areas which are allowed to regenerate naturally are of particular benefit to foraging chicks. Not only do they support their preferred prey types in higher numbers they also provide an essential refuge from in-field activities such as agrochemical spraying and irrigation. Previous research has shown that permanent cover leads to increased brood size and chick survival of grey partridge chicks on agricultural land (Panek 1997).

Set-aside areas were common under the CAP scheme which paid farmers to take land out of production to try to balance the market. The increased demand for produce has seen much of this land re-cropped over the past two years (Europa 2007). This study supports others in suggesting that the loss of CAP set-aside areas may prove to be detrimental to the breeding success of Galliformes, and other farmland birds (Kubišta 1990; Corbet 1995; Steffan-Dewenter and Tscharntke 1997; Poulsen et al. 1998; Henderson et al. 2000; Donald et al. 2001a; Steffan-Dewenter and Tscharntke 2001; Vickery et al. 2004; Kaiser et al. 2006). It is essential that agri-environment schemes that will encourage farmers to keep these pockets of land out of production are considered. It must also be noted that some management of these areas outside of the breeding season is essential to prevent succession into scrub and woodland, since these habitats are avoided by breeding pheasants (Hill 1985; Bliss 2004; Bliss et al. 2006; Draycott et al. 2009).

104 6 DIETARY AND BEHAVIOURAL COMPARISON OF HUMAN- IMPRINTED GREY PARTRIDGE AND PHEASANT CHICKS

The grey partridge is a lowland gamebird that, like the pheasant, is commonly found on arable farmland during the breeding season. Grey partridge numbers across Europe have declined since the 1950s, primarily due to the increased use of herbicides (Southwood and Cross 1969; Rands 1985; Sotherton and Robertson 1990). As with pheasant chicks, grey partridge chicks require a high number of invertebrates in their diet for successful growth and development. Herbicides influence partridge numbers indirectly by causing a decline in these invertebrate prey items leading to an increase in chick mortality. To halt this decline some agri-environment schemes have been aimed at increasing invertebrate diversity and abundance and providing suitable brood-rearing cover on farmland.

This study compares the diet and behaviour of foraging grey partridge chicks with that of pheasants in an attempt to illustrate the similarities and differences between these species. Chicks of both species were together imprinted onto a human handler and mixed-species broods used in field trials. No difference in diet was detected, nor were any major variations in behaviour observed. This implies that agri-environment practices aimed at improving the breeding success of one of these two species are likely to benefit the other. It also supports the use of results obtained from one species being extrapolated to the other, including those discussed previously in this thesis.

6.1 Introduction

The pheasant is the most commonly shot gamebird in the UK (Canning 2005) and is reared and released in large numbers throughout Europe and America. Consequently the population of wild pheasant in the UK is almost non-existent and in many places numbers are masked by released birds (Canning 2005). Other gamebirds also share their farmland habitat with the pheasant: the red-legged partridge ( Alectoris rufa ) and the grey partridge. The red-legged partridge’s natural range is south-western Europe but it has become naturalised in England, where it is also released for shooting (Heinzel et al. 1995; Robinson 2005). The natural range of the grey partridge stretches across Europe, including the United Kingdom, and it has been released across much

105 of North America (Edminster 1954; Potts 1986). After the Second World War grey partridge numbers across Europe declined due to increasing rates of chick mortality (Blank et al. 1967), triggering a switch in shooting from wild grey partridges to reared and released pheasants and red-legged partridges (Potts 1986). Hereafter ‘partridge’ refers to the grey partridge unless indicated otherwise. Weather is known to have a major influence on annual chick survival (Panek 1997; Draycott et al. 2002) and was the suspected cause of the partridge decline; however, fluctuations in weather did not correlate with the decline in bag records of the grey partridge (Potts 1986). Herbicides were introduced in the 1950s and their use has since become widespread; the decline in partridge numbers across Europe can be linked to this change in agriculture with lags occurring in countries where wide-spread herbicide use came later such as Poland, France, Hungary and the Netherlands (Potts 1986; Kuijper et al. 2009). The subsequent decrease in weed diversity on farmland led to the decline in insect diversity as their food plants and shelter disappeared (Southwood and Cross 1969; Rands 1985). Grey partridge chicks, like pheasant chicks, require invertebrates during their early weeks to gain the proteins they require for successful growth (Southwood and Cross 2002). The decline in their insect prey led to the decreased survival rates of partridge broods (Southwood and Cross 1969; Potts 1986). Other secondary factors contributed to their decline such as the loss of gamekeepers after the war leading to increased predation rates and the loss of suitable habitat as arable farming intensified (Potts 1986). These factors combined have also affected many other farmland birds including the pheasant and ground-nesting farmland birds such as the skylark, lapwing and corn bunting (Siriwardena et al. 1998; Wilson et al. 2001; Whittingham and Evans 2004; Winspear and Davies 2005; Firbank et al. 2008).

The grey partridge is considered to be vulnerable across Europe due to its declining populations (Tucker and Heath 1994; EBCC 2000). In order to preserve and increase populations of grey partridges and other farmland birds it is important to preserve their habitats and prey populations. As discussed in Chapter 5, preserving non- cropped areas on arable farmland benefits pheasant chicks by providing them with an optimum source of prey, and with shelter. Although originally a steppe or grassland species the grey partridge is found on arable farmland with broods being raised in the same habitats as pheasant chicks (Potts 1986). It is therefore likely that factors benefitting one species will also benefit the other. This study aimed to test this

106 hypothesis by comparing the diets of pheasant and grey partridge chicks foraging in the same habitat.

Grey partridges, unlike pheasants, form monogamous pairs during mid to late winter and remain together throughout the breeding season (Edminster 1954). Nests are commonly built in field margins and building begins during April (Edminster 1954), with ideal nesting habitats being incomplete hedgerows or grass tracks with cover along one edge only (Cross 1966). Conservation headlands were the original agri- environment scheme prescribed to increase partridge brood survival (Potts 1986) and it could be expected that other schemes aiming to increase invertebrate abundance will benefit the partridge. The partridge also differs from the pheasant in that once the chicks have hatched both parents play a role in looking after their brood (Edminster 1954; Potts 1986). Although there is some evidence that partridge parents teach their chicks to eat insects (Potts 1986) other studies have made use of the innate feeding behaviour and food preferences of grey partridge chicks (Regenscheid et al. 1987; Herrmann and Fuchs 2006; Moreby et al. 2006).

6.2 Methods

In 2009, 60 grey partridge ( Perdix perdix ) eggs were purchased from Fasanerie Manfred Renger (Herzberg, Germany) and 60 pheasant eggs from the Velký Karlov game farm. The partridge eggs were incubated in the Brinsea Octagon 20 Advanced at 37 °C and 40 - 50% relative humidity. The pheasant eggs were incubated in the Brinsea Polyhatch as described previously (see Section 2.2.1), and all eggs were similarly monitored for humidity levels. Previous pheasant batches incubated this way had an incubation period of exactly 24 days and grey partridges are expected to take 23-25 days (M. Ford, GWCT, per. comm. 2009) so both species were placed into the incubators on the same day.

Upon hatching, chicks of both species were imprinted together for use in field trials as described in Section 2.2. To identify individuals, chicks were ringed using coloured aluminium rings that could be easily removed after the trials. Pheasant chicks had 4 mm yellow and red rings, whilst grey partridge took 3 mm pink and blue rings. Two pheasant and two grey partridge chicks were chosen at random to make up each brood

107 during the field trials. During June, 12 field trials were conducted in different habitat types: winter wheat (6), summer wheat (1), summer barley (3), game crop (2). These habitats were chosen to reflect samples taken from wild birds nesting or foraging in the same areas (Chapter 7) and also to increase the sample size of the spring sown cereals (Chapter 5).

6.2.1 Diet

Faecal samples were collected and analysed as in Section 2.2.3; two collection pens were used for each trial, one for each species. Correction factors were applied as established in Chapter 3. Due to the similarities between correction factors developed here for pheasant chicks and those developed for other birds (Custer and Pitelka 1974; Green 1984; Butler 2007) it was deemed acceptable to use the same factors for the grey partridge.

The number of invertebrates and the number of invertebrate groups eaten by the different species were tested using paired t tests on normalised data (square root of the counts). Differences in dietary composition between the species were tested using compositional analysis (Aebischer and Robertson 1993) with chick age also included as an explanatory variable with any non-significant interactions and terms removed stepwise. Invertebrates consumed were grouped into Araneae, Hemiptera, Hymenoptera, Coleoptera, ‘Larvae’ (containing Coleoptera, Lepidoptera and Tenthredinidae larvae) and ‘Other’ (containing Diptera, Orthoptera and any unidentified invertebrates). Log ratios were produced as in Section 4.2.1 and these values analysed in R (Ihaka and Gentleman 1996) using a MANOVA having first bound the invertebrate groups into a single response variable using the function cbind.

Invertebrate samples were also collected from each field using a sweep net and Vortis sampler (as described in Section 2.3) on the same day as the chick field trial. Dietary preference of the grey partridge chicks was investigated by comparing the proportions of each invertebrate group found in the chicks’ diet with the proportions found in the field (Hill 1985). The proportions were first normalised using arcsine and then tested using paired t-tests to remove any influence of date or habitat.

108 6.2.2 Behaviour

At every five minute interval during the field trial each chick was located (if possible) and its distance from the handler recorded. If a chick was touching the handler’s shoe a distance of zero was recorded, further distances were estimated to within the nearest metre. The first count was taken at five minutes into the trial to allow chicks time to spread out and explore their surroundings. At each count the number of each species visible was also recorded.

The number of chicks visible was tested in R using a GLM with binomial errors and species, habitat, time into trial and chick age as explanatory variables. The response variable was generated by combining the number of chicks visible and not visible using cbind. Distance from the handler was also tested in R using a GLM with species, age, habitat and the time into the trial as explanatory variables. All models were simplified step-wise to remove unnecessary terms and interactions.

6.3 Results

In early June, 34 (56.7%) pheasant and 22 (36.7%) grey partridge chicks hatched, with the grey partridges starting a day later than the pheasants. Another grey partridge chick hatched four days later and was excluded from trials due to the age difference. Four (17.4%) of the grey partridge chicks died within the first few days, whereas all of the pheasant chicks survived. Imprinting rates were similar for both species, with 82.4% of grey partridge and 87.9% of pheasant chicks successfully imprinting onto their human handlers. No grey partridge chicks and only one pheasant chick (3.3%) were lost in the field during these trials.

6.3.1 Diet

Pheasant chicks eat more invertebrates (t = -2.3, P < 0.05) and a wider range of invertebrate groups (t = -3.3, P < 0.01) than the grey partridge chicks (Figure 6.1).

109 60 Pheasant * (n=12) 50 Grey partridge (n=12) 40

30

Count ** 20

10

0 Number of invertebrates Number of invertebrate eaten groups eaten

Figure 6.1 The quantity and taxonomic diversity of invertebrate groups eaten by pheasant and grey partridge chicks (with standard errors). * indicates significance at α = 0.05, *** at α = 0.01.

At the level of order, however, no difference was found in the dietary composition of these two game species (F 5,18 = 1.78, Wilk’s Λ = 0.67, P = 0.17) (Figure 6.2). Chick age did not significantly affect dietary composition either (F 5,17 = 1.73, Wilk’s Λ = 0.66, P = 0.18), habitat was not tested due to the small sample size of individual habitats.

1.00 0.00 0.01 Araneida 0.19 0.90 0.22 Hemiptera Lepidoptera 0.80 0.03 0.04 Hymenoptera 0.70 0.13 Coleoptera 0.60 0.28 Other

0.50

0.40

Proportion in diet Proportion 0.61 0.30 0.40 0.20

0.10 0.04 0.00 0.04 Pheasant Grey partridge

Figure 6.2 The dietary composition of invertebrate groups eaten by pheasant and grey partridge chicks foraging together.

Within the order Hemiptera no difference in composition was detected (F 2,18 = 2.4,

Wilk’s Λ = 0.79, P = 0.12); nor was any found within the order Hymenoptera (F 2,21 = 1.74, Wilk’s Λ = 0.86, P = 0.20). Chick age had no significant effect for either order

(Hemiptera: F 2,17 = 0.10, Wilk’s Λ = 0.99, P = 0.90; Hymenoptera: F 2,20 = 2.2, Wilk’s Λ = 0.82, P =0.13).

The sweep net and Vortis samples gave similar results so only those from the sweep net will be discussed here. Hymenoptera (t 11 = 3.72, P < 0.01) and Coleoptera (t 11 = 4.59, P < 0.01) were found in greater proportions in the diet of the grey partridge than in the field. The proportions of Hemiptera (t 11 = -8.60, P < 0.001) and ‘Other’ (t 11 = - 4.51, P < 0.01) were greater in the field than in the chicks’ diet (Figure 6.3). 0.8 *** Vacuum a 0.7 ** (n=12) a ** 0.6 Sweep ** (n=12) 0.5 a Diet a (n=12) 0.4 a a 0.3 b

Proportion 0.2 b b 0.1 b b b 0

Figure 6.3 Comparing proportions of invertebrate orders found in the field by vacuum sampling and sweep netting with the proportions found in the diet of grey partridge chicks (with standard errors). ** indicates significance at α = 0.01, *** at α = 0.001.

6.3.2 Behaviour

During the trials the interactions between species and habitat and between species and chick age significantly affect number of chicks visible (Table 6.1). There appears to be a positive relationship between the number of chicks visible and chick age with the grey partridges and a negative relationship for the pheasants (Figure 6.4). In the commercial crop fields there is no different between the species regarding how many chicks are visible (t = -0.004, P = 0.997) but in the game crop areas the grey partridge were significa ntly more visible (z = 02.88, P < 0.01) (Figure 6.5); however the small sample size of the game crop habitat (n = 2) makes this result unreliable.

Table 6.1 GLM results showing variables affecting the number of chicks visible during field trials. Variable t value P value Species 1.96 0.05 Habitat 1.35 0.18 Time into trial -2.22 0.03 * Chick age 0.30 0.76 Species:Habitat -2.17 0.03 * Species:Age -1.98 0.05 * Time:Age 2.09 0.04 * * indicates significance at α = 0.05.

Figure 6.4 The interaction between chick age and species on the number of chicks visible over the field trials.

1.2 * Pheasant 1 Grey Partridge

0.8

0.6

0.4

Proportion Proportion ofchicksvisible 0.2

0 Commercial crops Game crop (n=2) (n=10) Habitat

Figure 6.5 The average number of chicks visible during field trials in different habitat types . * indicates significance at α = 0.05.

The grey partridge chicks stayed significantly closer to their human handler than the pheasant chicks (Figure 6.6). Distance was also signif icantly influenced by the three - way interaction between habitat, time into the trial and chick age but no interaction with species was significant (Table 6.2) .

***

(n=12) (n=12)

Figure 6.6 Average distance between chicks and their hum an hander (with standard errors). *** indicates significance at α = 0. 001.

Table 6.2 GLM results showing variables affecting the distance of foraging chicks from their human handler.

Variable t value P value Species 3.84 <0.001 *** Habitat 2.88 0.004 ** Time into trial 2.99 0.003 ** Chick age 5.46 <0.001 *** Habitat:Time -3.96 <0.001 *** Habitat:Age -2.89 0.004 ** Time:Age -3.37 <0.001 *** Habitat:Time:Age 4.04 <0.001 *** ** in dicates significance at α = 0.01, *** at α = 0.001 .

6.4 Discussion

Pheasant chicks appear to eat more invertebrates and to eat more invertebrate ty pes than the partridge chicks. T his is likely to be due to their larger size since larger chicks will require more nutr ients and will therefore have to eat more. Pheasant chicks have also been found to have a higher peck rate than the grey partridge (Kimmel 1990); assuming the same peck success rate between species this would lead to the pheasants consuming more invertebrates. By eating more invertebrates they are also likely to eat more invertebrate taxa by chance, since although preferences occur chicks tend to eat whatever is available to them. Being larger, the pheasants will also be able to tackle larger prey items than the grey partridge, meaning a greater range of taxa are available to them. Interestingly, there was no difference in the composition of the chicks’ diet between the two species at the level of order; nor was there any different in dietary composition within the orders Hymenoptera or Hemiptera. This implies there is no difference in preference for different prey between pheasant and partridge chicks at the level of order or family. This is supported by the comparison of the partridge’s dietary preference with that of the pheasant (Section 5.3.1); both species show a significant preference for Hymenoptera and Coleoptera and avoid Hemiptera and ‘Other’. The group ‘Other’ is principally composed of Diptera, implying that flies are avoided by these chicks, possibly because they are difficult to catch and often remain out of reach. Previous research has found that Heteroptera, sawfly larvae and carabid beetles are most preferred by partridge chicks (Vickerman and O'Bryan 1979; Hill 1985; Potts 1986; Potts and Aebischer 1991). Discrepancies may be due to differences in year, location, habitat type, sampling method or a combination of these factors.

Previous studies of mixed-species broods found that pheasant chicks were more aggressive and dominated the brood (Kimmel 1990). No such bullying was observed during this study, although the pheasant chicks appeared more energetic and adventurous. Partridge chicks appear to stay closer to their human handler than the pheasant chicks. One reason for this difference may be that they imprint more strongly than the pheasant chicks, since chicks that have a weaker imprinting instinct will be expected to wander further from their mother. Similar success rates at imprinting were found between the two species however, implying that their imprinting instinct is of equal strength. Another possible reason for this difference in distance may be simply due to the size difference between the species. Grey partridges are smaller than pheasants and the reduced distance may simply be in proportion to their size. Unfortunately, no biometrics were taken so this hypothesis remains untested. The three-way interaction between habitat, chick age and time into

114 trial makes it difficult to reach any meaningful conclusion. Ideally further studies would be conducted with grey partridge chicks in order to confirm these findings and investigate any other factors affecting their foraging.

The grey partridge shares similar arable habitats with the pheasant and as such management that is made for one species will likely affect the other. Grey partridges have declined over the past 60 years due to the decline in invertebrate prey on intensive farmland (Blank et al. 1967; Southwood and Cross 1969; Potts 1986). The decline in one game species has been balanced by the increased releasing of captively reared red-legged partridge and pheasant poults (Davey and Aebischer 2008). The disadvantage of this switch is that the habitat management for game is now focused on autumn and winter habitat requirements and so neglects the breeding season, a key period for grey partridge survival (Blank et al. 1967). In order to reverse the decline of grey partridges it is therefore important to provide good brood rearing habitat. This habitat must contain a high number of invertebrate prey and also provide adequate shelter and protection from predators. It is hoped that agri-environment schemes such as the Environmental Stewardship scheme in the United Kingdom will help maintain and increase populations of many farmland birds, including the grey partridge. In the UK the Biodiversity Action Plan (UK BAP) is a programme designed to evaluate, protect and restore the decline of biodiversity. The UK BAP has listed priority species and habitats for conservation which includes the grey partridge and certain arable features they use such as field margins, hedgerows and farmland (Anon 2007). Part of the plan includes the design and testing of AESs with respect to the grey partridge. The similarities in diet found by this experiment show that one way these schemes could be tested is to use human-imprinted pheasant chicks to determine which management prescriptions provide the best chick foraging habitats.

115 7 THE HABITAT USE AND DIETS OF SKYLARK AND LAPWING CHICKS SHARING ARABLE FARMLAND WITH BREEDING PHEASANTS

Previous chapters have investigated the diet and behaviour of gamebirds foraging in arable habitats, here the study is expanded to consider some of the wild farmland birds sharing the fields. Farmland specialists have declined over the past century due to the intensification of farming, which acts on different species in a variety of ways. This study focuses on three ground-nesting species: the skylark, lapwing and yellow wagtail. The diets of chicks of these three species were investigated by locating wild nests or broods and collecting faecal samples. The invertebrate component of their diets was compared with that of human-imprinted pheasant chicks to determine whether the latter could be used to investigate general foraging potential. No data on non-gamebird populations exists for the Seefeld estate so the territory density of breeding skylarks was also investigated.

Skylark territory density on the Seefeld estate is comparable with that found on arable land in the UK and varies across habitats as the breeding season progresses. The single field of sorghum contained the highest density of skylark territories and the lowest density was found in oil seed rape. Territory density was also negatively affected by vegetation height and boundary height. Human-imprinted pheasant chicks ate proportionally more Hymenoptera and Hemiptera than the wild skylark and lapwing chicks, whose diets also varied significantly from each other. A CCA plot shows the birds grouped by order with the lapwing overlapping with both the gamebirds and the passerines. All the species studies showed a preference for Coleoptera and a tendency to avoid Hemiptera, although this avoidance was not always significant. These similarities imply that there may be some benefit to wild birds, in particular ground feeding gamebirds and waders, from habitats managed for breeding pheasant populations.

7.1 Introduction

Farmland bird populations have declined over the latter half of the twentieth century, more so than any other group of bird species (Figure 7.1), and this decline has been greatest in farmland specialists (Siriwardena et al. 1998; BTO 2006).

116

Figure 7.1 Population trends in UK bird species compared with 1970 population levels, split by habitat type. (DEFRA 2009c)

This decline is caused by the increased intensification and mechanisation of farming (Warner et al. 1984; Fuller et al. 1995; Chamberlain and Fuller 2001; Newton 2004; Peach et al. 2004). These changes in farming practice have affected different farmla nd bird species in three main ways (O'Connor and Shrubb 1986; Green 1988; Stowe et al. 1993; Peach et al. 1994; Poulsen et al. 1998; Brickl e and Harper 1999; Chamberlain and Crick 1999; Donald et al. 2001a; Toepfer and Stubbe 2001; Wilson et al. 2001; Whittingham et al. 2005; Winspear and Davies 2005) :

1. Habitat structure Factors such as the decline in mixed farming, crop rotation and crop diversity have decreased the habitat heterogeneity of farmland. The decline in spring tillage and earlier harvests due to the planting of winter-sown crops reduces nest ing and foraging suitability as crops become denser and taller earlier in the year. It also increa ses nest damage due to farming activities. Hedgerow removal and drainage have also decreased the number of good foraging and nesting areas for different species. Species severely affected include: lapwing, turtle dove (Streptopelia turtur ), stone curlew (Burhinus oedicnemus ), skylark, yellow wagtail, song thrush (Turdus philomelos ), yellowhammer, cirl bunting (Emberiza cirlus ), reed bunting, corncrake and snipe.

2. Food availability (over-winter) The loss of over-winter stubble due to the wide spread sowing of winter-sown crops has decreased over-winter foraging opportunities for many species. Increased use of pesticides has compounded the problem. Species severely affected include: skylark, yellowhammer, cirl bunting, reed bunting and corn bunting.

3. Food availability (breeding season) Increased pesticide use decreases the availability of invertebrate and weed food. This, combined with a loss of suitable nesting habitats, leads to decreased juvenile survival. Species severely affected include: grey partridge, skylark, turtle dove, corn bunting and linnet (Carduelis cannabina ).

The effects of these changes on different bird species vary with the ecology of the species. It should be noted that these changes have not been studied for all species and are likely to impact in more ways and on more species than here discussed. The loss of invertebrate prey due to the increased use of pesticide has been discussed in Chapter 6 as it has been the main factor driving the decline of the grey partridge (Potts 1986; Ewald and Aebischer 2000). This loss of invertebrate prey affects all insectivorous birds, especially chicks which usually require much higher proportions of invertebrates than their parents (Holland et al. 2006). The change from spring to autumn or winter sowing of crops has adversely affected practically all farmland bird species at two crucial times of the year: over-wintering and breeding. The winter- sowing of crops removes over-winter stubble which provided an essential food source to many granivorous and insectivorous birds (Gillings et al. 2005; Perkins et al. 2008; Siriwardena et al. 2008). Winter-sown crops germinate earlier and create a taller, denser habitat during the breeding season; this is not ideal for either nest building or foraging (Poulsen et al. 1998; Chamberlain et al. 1999a; Browne et al. 2000; Wilson et al. 2001; Sheldon et al. 2004; Whittingham and Evans 2004; Winspear and Davies 2005). The drainage of wet meadows reduces soil permeability and adversely affects wader species such as common snipe and lapwing (Stoate et al. 1998; Winspear and Davies 2005; Bolton et al. 2007), whilst hedgerow removal affects many farmland

118 birds such as the yellowhammer, linnet, whitethroat (Sylvia communis ) and grey partridge (Stoate and Szczur 2001; Vickery et al. 2002; Winspear and Davies 2005).

Yellowhammers, linnets and many other farmland birds nest in the field margin and forage along field boundaries, farm tracks and within the fields while ground-nesting species such as the yellow wagtail, skylark and lapwing nest in the field. This study aims to determine the diet of birds nesting and foraging primarily within the crop fields focusing on the skylark, lapwing and yellow wagtail. The latter is only included from one nest and so is discussed in less detail than the skylark and lapwing. Yellow wagtails (Passeriforme: Motacillidae) are commonly found on farmland or estuaries (Robinson 2005) preferring soils which are more permeable as these areas hold an increased abundance of prey items above the soil (Gilroy et al. 2008). Yellow wagtails feed by taking insects off the ground or by catching them in the air, rather than by probing the soil in the manner of waders (Davies 1977). The breeding season and behaviour of the yellow wagtail and skylark are similar, although the yellow wagtail lacks the aerial display of the male skylark.

The skylark, lapwing and yellow wagtail require high proportions of invertebrates in their diets (Holland et al. 2006) and so should, in theory, benefit from management designed to increase invertebrate abundance. Whilst some evidence of this exists (Wilson et al. 1997; Vickery et al. 2002; Wrbka et al. 2008) it is difficult to test, since birds may travel a long way to forage and other aspects of vegetation structure will determine the foraging potential of a habitat patch (Wolda 1990; Cole et al. 2007). This study compares the diets of these three wild study species with the diet of human-imprinted pheasant chicks to determine whether the latter could be successfully used to assess foraging potential of habitats for other farmland birds.

7.1.2 Skylarks on arable land

The skylark is a small ground-living songbird (Passeriforme: Alaudidae) commonly found on grassland and farmland, particularly in treeless areas, across western Eurasia and into north Africa (Heinzel et al. 1995). Studies have shown that a tall dense field boundary will result in lower skylark territory density than more open field edges (Wilson et al. 1997; Poulsen et al. 1998). During the breeding season male skylarks

119 find and hold a territory of suitable breeding habitat. Male skylarks have an obvious display flight and a high-pitched musical song, which they deliver whilst flying up to 100 m high where they circle their territory before descending in a series of diving and hovering movements (Heinzel et al. 1995). These display flights vary in length from short flights of a few minutes to long flights sometimes lasting over 40 minutes (pers. obs.). The females also sing but this tends to be less frequently and with shorter song flights. Skylark pairs will often be seen foraging together with the male following the female around the foraging ground in a series of short flights. Although the female does all the incubating, both parents will help feed the chicks, especially just before they fledge when they require a larger quantity of food. Both adult and young skylarks require a large proportion of invertebrates in their diet (Holland et al. 2006).

The highest skylark territory densities in the UK are found during April to June and are on areas of set-aside and spring-sown cereals rather than winter-sown cereals (Poulsen et al. 1998; Chamberlain et al. 1999a; Browne et al. 2000; Donald et al. 2001a). Actual numbers are higher on winter-cereals since these cover a much larger land area (Browne et al. 2000). Over the breeding season habitat use by the skylarks shifts as winter-sown cereals become too tall and dense and spring-sown crops germinate (Poulsen et al. 1998; Toepfer and Stubbe 2001). Skylarks prefer shorter and less dense vegetation between 15 and 50cm high (Wilson et al. 1997; Wakham- Dawson et al. 1998; Chamberlain et al. 1999a; Toepfer and Stubbe 2001). Exact values differ between studies due to other factors such as behaviour; it is likely that the shorter vegetation will be better for foraging whilst slightly taller (20-50cm) vegetation provides better nesting cover. Skylarks often forage in bare patches and tramlines even though these areas tend to have a lower abundance of insect prey than the surrounding crops (Odderskær et al. 1997; Wakham-Dawson et al. 1998). This is probably because these areas are more easily accessible and provide a better view of approaching predators. Tramlines can be detrimental to skylark populations though as they provide routes through the field for ground-based predators. Predation, especially from mammals, is the main cause of nest failure (Wilson et al. 1997; Donald et al. 2002) and predation rates are highest next to tramlines (Donald et al. 2002). Whilst skylark territory densities are higher on areas of set-aside than in the cereal crops,

120 survival is lower, probably due to the density-dependant effect of predation from a high number of skylarks in a relatively small area (Donald et al. 2002).

Although the skylark is listed as of ‘least concern’ in the IUCN Red List (IUCN 2009) due to its extensive range, populations across Europe have declined significantly (Tucker and Heath 1994; Browne et al. 2000; EBCC 2000). This decline is attributed mainly to the loss of suitable foraging habitat, although it is likely the decline in available invertebrate prey augments this (Wilson et al. 1997; Holland et al. 2006). The increase in winter-sown crops has created a denser and taller habitat than spring- sown crops create, particularly early in the breeding season, which makes foraging more difficult (O'Connor and Shrubb 1986; Chamberlain et al. 1999a; Browne et al. 2000; Donald et al. 2001a; Toepfer and Stubbe 2001). The UK population declined by 55% during the last quartile of the twentieth century (Chamberlain and Crick 1999) and the Austrian population is also declining, although less rapidly (Tucker and Heath 1994). At a European level the skylark is considered vulnerable and of conservation concern at level SPEC 3 (Species of European Conservation Concern) due to its rapid decline and depleted population (Tucker and Heath 1994). The skylark is on the UK Red List since it has not shown a significant recovery since its decline (Robinson 2005).

7.1.3 Lapwings on arable land

The northern lapwing, here simply referred to as the lapwing, is a large plover (Charadriiforme: Charadriidae) found all across Europe and western Eurasia with some populations over-wintering in north Africa (Heinzel et al. 1995). Lapwings are commonly found on areas of wet grassland, marsh and bog but also on short turf and farmland. In the UK 95% of lapwings are found on farmland, reflecting the dominance of this habitat (Wilson et al. 2001). Large over-wintering populations are often found on estuarine and coastal mudflats and sandbanks (Heinzel et al. 1995).

Lapwings begin breeding early in the season and reach their peak breeding density in April, earlier than the skylark and yellow wagtail (Robinson 2005). Although originally a wetland bird, lapwings can often be found on cereal crops and rough grazing, and show a tendency to prefer spring-sown cereals (Johansson and Blomqvist

121 1996; Wilson et al. 2001). Predation rates on arable land tend to be lower than on grassland but the destruction of nests and increased disturbance due to cultivation can be a major problem (Galbraith 1988; Blomqvist and Johansson 1995). Upon hatching, chicks tend to remain in, or near, the nest for the first couple of days, before the parents lead them to better foraging areas, often areas of adjacent grassland (Galbraith 1988; Blomqvist and Johansson 1995; Johansson and Blomqvist 1996).

The lapwing is of similar conservation status to the skylark, being on the UK Red List and of European SPEC 2, and is vulnerable as its population is also concentrated in Europe (Robinson 2005). Numbers in the UK have declined by nearly 50% over the last decade of the twentieth century (Wilson et al. 2001), however populations in Austria have shown a slight increase (EBCC 2000). Globally lapwings have a large range and their decline is not rapid enough to count as threatened on the IUCN Red List, leaving them as another species of least concern (IUCN 2009).

7.2 Methods

The data for this chapter were mainly collected by two students as part of their Master’s degrees. During 2008 a pioneering study of breeding behaviour of skylarks on the Seefeld estate was carried out. The methodology was altered for the 2009 project to focus on nestling diet and expanded to include other farmland chicks.

7.2.1 Breeding skylark territories

During 2008 skylark territories around Seefeld were mapped on 24 fields during early May and early June. Fields were surveyed for between half an hour and one hour (depending on field size) by walking the perimeter and pausing at suitable view points to observe song flights. The number of displaying males was counted in each field and the maximum number of singing males at a time was taken as the number of territories within each habitat. If a territory was observed to cross into an adjacent habitat each was said to contain 0.5 territories (Wilson et al. 1997; Poulsen et al. 1998). Sketch maps were used in the field to determine the territory locations. The fields were divided up into two sets (A and B) and within each set three or four adjacent fields were clumped together to make up a survey group. Survey groups were

122 visited four times a day: early morning, late morning, early afternoon and late afternoon. To ensure no bias due to daily activity cycles the groups were rotated within the set so each field was surveyed at all times of day (Poulsen et al. 1998) giving four counts, the highest of which was taken as the number of territories. For each set the mid-season surveys began a month after the early-season ones, giving another four counts. Surveys were only carried out in dry weather with a light wind since males tend to avoid displaying in adverse weather (Wilson et al. 1997). If a field was being sprayed or was otherwise disturbed the survey was postponed for a day.

In 2009 a smaller scale study was carried out in conjunction with intensive nest finding efforts. Due to the main aim of this study being chick diet, fewer fields were surveyed and a less structured surveying schedule adhered to. Territories were mapped in late April, early May, late May and early June based on surveys lasting at least an hour, often longer, where the observer sat in a hunting hide, car or at the field’s edge.

Vegetation surveys were performed as described in Section 2.5, although only the Robel pole and quadrat were used. The field boundary was categorised using an arbitrary system developed by Poulsen and colleagues (1998). The boundary types were scored as follows:

0: adjacent crop, track, short grass 1: tall grass, scrub, set-aside, small scrubby hedgerow 2: bushy hedgerow with some trees 3: tall thick hedgerow containing or entirely made up of a line of trees 4: woodland

The boundary index was calculated by multiplying the length of each boundary type by its type score. Due to the disparity in field size this value was then divided by the field size. Boundary indices were calculated for each field surveyed and for each crop type within each field.

The territory data from the two years were combined and tested using a GLM with territory density as the response variable. Explanatory variables considered were crop

123 type, vegetation structure, boundary index, the presence of set-aside and season. These explanatory variables were investigated and those which correlate to each other were removed from the final GLM. This model was then simplified step-wise to remove non-significant interactions.

7.3.2 Diet of wild farmland birds

In April 2009 breeding lapwing, skylark, yellow wagtail and yellowhammer were observed on many fields around the Seefeld estate to identify those more likely to yield faecal samples. Fields close to the central offices and those with good observational vantage points were chosen to survey in more detail. Yellowhammers were removed from the study as they nest in hedgerows and it was decided to focus the study on ground-nesting birds within the fields. The crop types focused on changed with the season as the winter wheat became too long to successfully observe behaviour, and the other crop types began to grow.

Skylark and yellow wagtail nest finding

Starting with the nearest and most easily observed, fields were surveyed from dawn until midday to observe breeding behaviour. Each field was observed for a minimum of one hour and if no birds were seen moving in the field a second field was attempted. Fields were surveyed until the observer had an accurate sketch of where the birds were, and on average two to three hours were spent on each field. Some fields contained hunting hides which were ideal for observing bird behaviour due to their elevated viewpoint. In most other fields a car was used as a mobile hide, as birds do not associate its shape as a threat (A. Hoodless, GWCT, per. comm. 2009). If this was not possible the observer sat at the field edge, near taller vegetation in order to break up their outline. Often the two or three observers split up to cover more fields or the same field from different angles. Territory maps were established from sketch maps drawn in the field and breeding pairs favouring areas near the edge of fields or good observational spots were selected for more focused study. Pairs towards the middle of the field were observed but were deemed too far away to observe the exact nest location with the equipment available (10 x 42 binoculars). Breeding behaviour observed included male song flights, joint feeding forages, nest building and food

124 carrying. By focusing the study on pairs nearer the field margins it was more likely that nest building and chick feeding behaviour would be observed. Even in cases where skylark nests were not found, it was possible to determine the breeding stage of the pair by their behaviour (Table 7.1). Yellow wagtails showed similar behaviours, with the exception of the male display flights. The yellow wagtail has a fast, undulating flight and often flies fairly low above the field making it difficult to follow.

Table 7.1 . Behaviour displayed by breeding skylarks Stage Observations Territory formation Many males displaying. Positions often change. Nest building Many short flights to gather nesting material. Often returns directly to the nest site. Incubation Only the male obvious. Female will leave her eggs inconspicuously for feeding forages approximately once an hour. Chicks Parents observed carrying food to the nest. Often land away from the nest and walk back. Food forays become more frequent as the chicks get older. Fledging Both parents bring food, but do not return to the nest site. (chicks out of nest, not yet Sometimes return to more than one spot in the field if independent) chicks have split up.

Once a likely pair had been located two or three observers watched the pair from different angles. When a bird dropped repeatedly in the same spot, particularly when carrying food or nesting material, one person walked into that spot, a thin bamboo cane was inserted as a marker and a search of that area made. Often three or more bamboo canes were placed to home in on the nest location before an extensive search of the area was made by all field workers available (usually two). Searches were only made on warm, dry days, after the early-morning foraging trip. To minimise disturbance searches lasted no longer than 30 minutes, usually less, depending on weather conditions and bird behaviour. On discovering the nest a single bamboo pole was placed five paces away and the nest location from the pole carefully noted. If chicks were present they were carefully removed from the nest and any faecal sacs present removed with tweezers. Approximate chick age was estimated from size and feather development and a photograph taken for later comparison. Faecal samples were frozen and returned to the laboratory for faecal analysis as described in Section

125 2.2.3. Nests with chicks were visited at 2-3 day intervals to collect several samples from each nest and increase the age range sampled. More frequent visits were deemed unnecessary and potentially harmful to the chicks due to increased stress from handling and the danger of leading predators to the nest. For compositional analysis samples from each nest were pooled and age removed as a factor.

Lapwing brood finding

During the middle of the day, whilst skylarks are less active, fields were searched for lapwing nests and broods. During the initial surveying of the farm fields with lapwing activity were noted and chosen for more extensive surveying. As with the skylark surveys, hunting hides or a car were used to obtain a good view of the field. Lapwing behaviour was used to determine breeding stage. The alarm calls of parents still on eggs were less urgent than those with chicks. Once in position the observers waited quietly until the birds settled back down and watched the behaviour of returning females. If chicks appeared to be absent the locations of all sitting females in a field were noted and one observer walked to the locations to find the nests and count and weigh the eggs. With help from A. Hoodless (pers. comm.) it was possible to estimate incubation time remaining from egg weight. Nests were monitored from both the field’s edge, by checking on female behaviour, and by visiting the nests close to the suspected hatching date. Females observed with chicks in the field were watched until the location of all chicks was known, after which one person walked to those locations. The first response of the lapwing chicks to disturbance is to sit down and rely on their camouflage plumage, which makes them ideal for collection provided an accurate fix was taken of their positions. Chicks were handled or placed into bird bags until they defecated; chicks were handled for approximately 10 - 20 minutes depending on age and condition. Faecal samples were obtained from the entire brood, if possible, and were frozen for later analysis (see Section 2.2.3). Chicks were also marked with permanent coloured pens on their pale belly to identify each brood. Marking on the underside ensured that the marked chicks would not be more visible to predators. Samples were not obtained more than once from each brood, due to chance rather than design. Chicks were released to the same location in which they were found and the researchers left the field as quickly as possible returning to the hide or car (if present) to ensure the female returned.

126 Comparison with the diet of human-imprinted pheasant chicks

Field trials using human-imprinted pheasant chicks (Section 2.2.1 and 2.2.2) were conducted in early June on all fields where faecal samples had been collected from wild birds. Faecal samples were collected from the pheasants and their diet compared with that of the wild chicks. The number of invertebrates and invertebrate groups consumed by the three different species were tested using two ANOVAs on normalised data (square root of the counts). Differences in dietary composition between the species were tested using compositional analysis (Aebischer and Robertson 1993) with species, chick age, habitat and month being included as explanatory variables. All non-significant interactions and terms were removed from the model stepwise. Invertebrates consumed were grouped into Araneae, Hemiptera, Hymenoptera, Coleoptera, ‘Larvae’ (containing Coleoptera, Lepidoptera and Tenthredinidae larvae) and ‘Other’ (containing Diptera, Orthoptera and any unidentified invertebrates). Log ratios were produced as in Section 4.2.1 and these values analysed in R using a MANOVA having first bound the invertebrate groups into a single response variable using the function cbind. Each wild species’ diet was compared with the pheasant chicks’ diet using a MANOVA and a ranking matrix produced comparing the log-ratios of all group pairings within the diet to determine which groups were causing the differences. The t values required in the matrix were calculated from F values generated by an ANOVA test. Using ANOVA rather than t- tests allows any interaction between factors to be accounted for.

Canonical correspondence analysis (CCA) was used to test the effect of vegetation height and percent cover along with date on chick diet in MVSP. Chick age was excluded since data from the passerine nests were pooled. Grey partridge data from Chapter 6 has been included in this study since these chicks were used in the same field trials as the pheasant chicks. The prey items were considered at their lowest possible grouping although unidentified items were removed from the analysis. Any prey item occurring less than three times was deemed rare and removed from this analysis to prevent them skewing the results (Shaw 2003). During analysis rare species were also down-weighted by the program. To avoid redundancy only variables with a variance inflation factor (VIF) under 20 was retained in the analysis (Ter Braak 1986). Pearson’s product-moment correlation test was then used to test

127 each variable against the CCA case scores for axes one and two. A significant correlation indicates that variable has an effect on chick diet.

7.3 Results

During 2008, skylark territories were successfully identified but no nests were found. This led to modifications of the methods during 2009 to focus on nest finding. This meant the addition of dietary data to compare with the diet of the imprinted pheasant chicks but a reduction in territory data collected in 2009.

7.3.1 Skylark territories

A GLM of crop and season on territory density can be simplified by removing season from the model. Crop type significantly influences territory density (Table 7.2), with territory density being significantly lower on oil seed rape than sorghum, sugar beet and spring wheat. Territory density is also higher on sorghum than on potato, spring barley and winter wheat (Figure 7.2). The territory densities found in this study are similar to those found on comparable habitats in the UK (Chamberlain et al. 1999a; Browne et al. 2000). Some effects of season can be seen in Figure 7.2; over the breeding season territory density on sugar beet, potato, spring wheat and maize appears to increase whereas on winter wheat and sorghum territory density appears to decrease.

Table7.2 GLM results showing how crop type influences territory density T value P (Intercept) 3.83 < 0.001 *** Maize -1.64 0.105 Oil seed rape -3.27 0.002 ** Potato -2.02 0.046 * Sugar beet -0.83 0.412 Spring barley -2.21 0.030 * Spring wheat -0.83 0.408 Winter barley -1.62 0.108 Winter wheat -2.10 0.039 *

128

Figure 7.2 Territory densiti es on different crop types (n varies) (with standard errors) .

Vegetation structure can be considered more important than crop type; v egetation cover correlated positively with vegetation height (r = 0.74, P < 0.001) so only height is used in this analysis. Vegetation height is a product of crop type (F 8,83 = 9.07, P <

0.001) and season (F 3,88 = 12.54, P < 0.001) hence crop type and season have also been removed from the analysis.

The GLM results (Table 7.3 ) indicate that territory density is significantly affected by vegetation height and boundary index but not the presence of set -aside areas within the field. Skylark territory density is greatest at low vegetation heights (Figure 7.3a) , also low vegetation cover, and low values of the boundary index (Figure 7.3 b). A low boundary index value means the field bounda ries are low with no, or very few , trees.

Table 7.3 GLM results showing variables affecting skylark territory density. Variables t value P value Vegetation height -2.20 0.031 * Boundary index -2.76 0.007 ** Set-aside presence -0.95 0.345 * in dicates significance at α = 0.0 5, ** at α = 0.01. (a) 0.6

0.5

0.4

0.3

0.2

0.1

0 0 20 40 60 80 100 120 140 Vegetation height (cm)

(b)

Figure 7.3 Relationship between skylark territory density and (a) vegetation height , (b) boundary index.

7.3.2 Diets of wild birds

In total 11 skylark and three yellow wagtail nests were found , of which six and one (respectively) hatched . Fourteen lapwing nests were found, only two of which yielded faecal samples, and a further 18 lapwing broods were found away from their nests . Of those that hatched only three skylark (27.3%) and one yellow wagtail (33.3%) broods survived until fledging; the rest were either lost prior to hatching due to abandonment or predation (60.0%) or predated as chicks (27.3%). Brood fate of the lapwing clutches was less certain but at least three nests (21.4%) were destroyed by farming activities. The majority of lapwing chicks were less than a week old (85.0%) with only three individual chicks of eight days or older caught. The average clutch size was 3.4 eggs, most of which may be assumed to hatch considering the majority of broods (81.3%) found aged under a week old contained three or four chicks. Either the older chicks spread out so much that only one per brood was ever seen, or most of the brood died before fledging. All of the yellow wagtail nests were found in winter wheat. The skylark nests were also found in winter wheat, with one exception where the nest was in summer barley but all foraging trips observed over three days were to an adjacent winter wheat field. Lapwing nests were found in winter wheat (6), game crop (5) and maize (3), these latter two habitats being bare earth when the nest were built up until the beginning of June. Lapwing broods were also found in winter wheat (11), game crop (4) and sugar beet (3).

Dietary preferences

The non-cereal crop fields were bare until June so sweep net samples were impossible for six of the 14 lapwing samples. For this reason the Vortis samples will be used in the analysis, sweep net results either comply with the Vortis or are non-significant. The proportion of Coleoptera in the lapwing chicks’ diet was significantly greater than in the field (t 13 = 5.62, P < 0.001) whilst the proportions of Araneae (t 13 = -2.55,

P < 0.05), Hemiptera (t 13 = -2.96, P < 0.05), Larvae (t 13 = -2.33, P < 0.05) and ‘Others’

(t 13 = -5.41, P < 0.001) are greater in the field (Figure 7.4).

131 0.8 *** c *** Vacuum 0.7 (n=7) 0.6 a Sweep ** (n=4) 0.5 Diet 0.4 b (n=14) a 0.3 * ab b Proportion * ** b a b 0.2 a ab 0.1 a ab b a b b c 0

Figure 7.4 Comparing proportions of invertebrate orders found in the field by vacuum sampling and sweep netting with the proportions found in the diet of lapwing chicks (with standard errors). * indicates significance at α = 0.05, *** at α = 0.001 when comparing vacuum samples and diet, different letters denote significance.

Skylark chick diets contain proportionally more Coleoptera (t 5 = 4.73, P < 0.01) than the Vortis samples and fewer Hymenoptera (t 5 = -2.74, P < 0.05) and ‘Others’ (t 5 = - 8.16, P < 0.001) (Figure 7.5). None of the comparisons with sweep net samples proved significant. Since there were only data from one yellow wagtail nest it has not been statistically analysed, although these chicks appear to prefer Araneae, Larvae and Coleoptera and avoid Hemiptera (Figure 7.6). 0.8 *** ** b Vacuum 0.7 (n=5) 0.6 a Sweep (n=5) 0.5 * Diet 0.4 a (n=6) a a 0.3 ab Proportion 0.2 a b 0.1 b 0

Figure 7.5 Comparing proportions of invertebrate orders found in the field by vacuum sampling and sweep netting with the proportions found in the diet of skylark chicks (with standard errors). * indicates significance at α = 0.05, ** at α = 0.01, *** at α = 0.001 when comparing vacuum samples and diet, different letters denote significance.

0.6 Vacuum 0.5 (n=1) Sweep 0.4 (n=1) Diet 0.3 (n=1)

0.2 Proportion 0.1

0

Figure 7.6 Comparing proportions of invertebrate orders found in the field by vacuum sampling and sweep netting with the proportions found in the diet of yellow wagtail chicks.

Range of invertebrates eaten

The pheasant chicks ate significantly more prey items than either the skylark or the lapwing (F 2,30 = 9.46, P < 0.01); both these wild birds ate a similar number of prey items. The pheasant chicks also ate significantly more invertebrate groups than the lapwing chicks (F 2,30 = 3.74, P < 0.05). Yellow wagtail data have been excluded from the analysis due to the data being from a single nest, although it has been included in Figure 7.7. 60 ** a Pheasant (n=12) 50 Skylark (n=6) Yellow wagtail (n=1) 40 b Lapwing (n=15) 30 * b Count 20

a ab 10 b

0 Number of invertebrates Number of invertebrate eaten groups eaten

Figure 7.7 The quantity and taxonomic diversity of invertebrate groups eaten by human- imprinted pheasant chicks and wild skylark, yellow wagtail and lapwing chicks. * indicates significance at α = 0.05, ** at α = 0.01 , different letters denote significance. Compositional analysis

Compositional analysis shows that the diet of skylark chicks differs significantly from that of human-imprinted pheasant chicks (F 5,15 = 13.53, Wilk’s Λ = 0.18, P < 0.001). Proportionally more Araneae and fewer Hymenoptera were found in the diet of skylark chicks (Figure 7.8) (Table 7.4). No significant difference was found between the relative proportions of different hymenopteran groups (F 2,17 = 1.83, Wilk’s Λ = 0.82, P = 0.19). No other variables modelled were significant. Due to only one yellow wagtail nest being found yellow wagtail diet cannot be analysed statistically (Figure 7.6).

Other Coleoptera Hymenoptera Larvae Hemiptera Araneae 1.00 0.01 0.01 0.05 0.00 0.11 0.90 0.01 0.18 0.22 0.06 0.22 0.33 0.80 0.03 0.08 0.04 0.12 0.07 0.70 0.00 0.60 0.28 0.21 0.50 0.47 0.58 0.40 0.10

Proportion Proportion in diet 0.65 0.30 0.08 0.40 0.20 0.28 0.10 0.22 0.13 0.03 0.00 0.04 Lapwing Pheasant Grey partridge Skylark Yellow Wagtail

Figure 7.8 Comparison of the dietary composition of human-imprinted pheasant and grey partridge chicks with wild lapwing, skylark and yellow wagtail chicks foraging on arable farmland.

Table 7.4 Ranking matrix of the relative differences between the diets of wild skylark chicks and human-imprinted pheasant chicks. Within the matrix (+) indicated a row taxa is found at greater proportions in the diet of skylarks, (-) means the opposite, triple sign indicates significance at α = 0.05. Numerator Denominator Rank Araneae Other Larvae Coleoptera Hemiptera Hymenoptera Araneae + + + +++ + 5 Other - +++ + +++ +++ 4 Larvae - --- + + + 3 Coleoptera - - - + + 2 Hemiptera ------+ 1 Hymenoptera ------0

134 The composition of chick diet varies significantly between the lapwing and human- imprinted pheasants (F 5,21 = 2.96, Wilk’s Λ = 0.59, P < 0.05). Dietary composition also varies significantly with habitat (F 5,21 = 4.93, Wilk’s Λ = 0.46, P < 0.05) and month (F 10,42 = 3.49, Wilk’s Λ = 0.30, P < 0.05). Wilk’s lambda indicates that month is the most influential factor affecting diet. A ranking matrix indicates that the main differences between the species is that ‘Other’ invertebrates are found in greater proportions in the lapwing’s diet and Hemiptera are found less (Table 7.5).

Table 7.5 Ranking matrix of the relative differences between the diets of wild lapwing chicks and human-imprinted pheasant chicks. Within the matrix (+) indicated a row taxa is found at greater proportions in the diet of lapwings, (-) means the opposite, triple sign indicates significance at α = 0.05. Numerator Denominator Rank Other Araneae Coleoptera Larvae Hymenoptera Hemiptera Other + + +++ + +++ 5 Araneae - + + + +++ 4 Coleoptera - - + + + 3 Larvae --- - - + + 2 Hymenoptera ------+ 1 Hemiptera ------0

No significant difference in composition was found within the group ‘Other’ (F 3,16 = 1.23, Wilk’s Λ = 0.81, P = 0.33); however, millipede fragments were present in 53.3% of lapwing faecal samples but were not found in the diet of any other species. Within the Hemiptera there was a significant difference in dietary composition between these two species (F 2,15 = 10.27, Wilk’s Λ = 0.42, P < 0.01) (Figure 7.9). Aphids make up a large proportion of the diet of the pheasant chicks whilst very few are found in the diet of lapwing chicks (Table 7.6). Lapwings eat a greater proportion of heteropteran bugs than the pheasant chicks. The faeces of most lapwing broods (60%) contain no Hemiptera fragments, whilst those of most pheasant broods did (80%).

135 1.00 0.06 Heteroptera 0.90 0.08 0.80 Other Homoptera

0.70 Aphididae

0.60 0.83 0.50 0.86 0.40 0.30 Proportion Proportion in diet 0.20 0.00 0.10 0.17 0.00 Pheasant Lapwing

Figure 7.9 Composition of Hemiptera in the diets of human-imprinted pheasant chicks and wild lapwing chicks foraging on arable farmland.

Table 7.6 Ranking matrix of the relative differences within the Hemiptera between the diets of human-imprinted pheasant chicks and wild lapwing chicks. Within the matrix (+) indicated a row taxa is found at greater proportions in the diet of lapwings, (-) means the opposite, triple sign indicates significance at α = 0.05. Numerator Denominator Rank Heteroptera Other Homoptera Aphid Heteroptera +++ +++ 2 Other Homoptera --- +++ 1 Aphid ------0

The lapwing and skylark chicks also ate significantly different proportions of these invertebrates (F 5,15 = 3.82, Wilk’s Λ = 0.44, P < 0.05); lapwings ate proportionally more Hymenoptera whilst skylarks ate proportionally more spiders (Table 7.7).

Within the order Hymenoptera there is a significant difference (F 2,9 = 4.44, Wilk’s Λ = 0.50, P < 0.05), with lapwings consuming a much higher proportion of ants and skylarks consuming a greater proportion of sawflies larvae (Figure 7.10) (Table 7.8).

Table 7.7 Ranking matrix of the relative differences between the diets of wild lapwing and skylark chicks. Within the matrix (+) indicated a row taxa is found at greater proportions in the diet of lapwings, (-) means the opposite, triple sign indicates significance at α = 0.05. Numerator Denominator Rank Hymenoptera Coleoptera Other Hemiptera Larvae Araneae Hymenoptera + + + +++ +++ 5 Coleoptera - + + +++ +++ 4 Other - - + + +++ 3 Hemiptera - - - + +++ 2 Larvae ------+ 1 Araneae ------0

136 1.00 0.03 Tenthredinidae 0.90

0.80 0.31 Other wasps 0.46 0.70 Formicidae

0.60

0.50

0.40 0.34 0.66 Proportion Proportion in diet 0.30

0.20

0.10 0.20 0.00 Lapwing Skylark

Figure 7.10 Composition of Hymenoptera in the diets of wild lapwing and skylark chicks foraging on arable farmland.

Table 7.8 Ranking matrix of the relative differences within the Hemiptera between the diets of wild lapwing and skylark chicks. Within the matrix (+) indicated a row taxa is found at greater proportions in the diet of lapwings, (-) means the opposite, triple sign indicates significance at α = 0.05. Numerator Denominator Rank Formicidae Other wasps Tenthredinidae Formicidae + +++ 2 Other wasps - + 1 Tenthredinidae --- - 0

Multivariate statistics

A CCA with date, vegetation cover and vegetation height shows some clear grouping of the chicks by family (Figure 7.11). The Galliformes (pheasant and grey partridge) group together at lower values of axes one and two whilst the Passeriformes (skylark and yellow wagtail) group together at low values of axis two and higher values of axis one. The lapwing chicks (Charadriidae) group at higher values of axes one and two but overlap with the passerines and slightly with the gamebirds.

137

Figure 7.11 CCA biplot of species including grey partridge (Chapter 6) . The environmental variables are: Day, date; Height, vegetation height; Vegetation, percent cover . Vector scaling 13.72.

Axis one has an eigenvalue of 0.323 and explains 8.84% of the variation whilst axis two has an eigenvalue of 0.189 and explains 5.12%. Date correlates negatively with both axes w hilst both vegetation variables only correlate with axis two, both negatively, although vegetation cover shows a much stronger correlation than vegetation height.

7.4 Discussion

The initial research into breeding skylarks in 2008 yielded good data on ter ritory density but no nests were found. It was decided to focus on nest finding in 2009 to gain dietary data that could be compared with the data collected from human - imprinted pheasant chicks. Due to the intensive nature of nest finding and the high rates of abandonment and/or egg predation only a small sample size was generated. Although few discovered nest s survived until fledging it is unlikely our actions were to blame since we kept disturbance to a minimum . The nests that were easier to find were often located next to tramlines or close to the field edge making them vulnerable to predation (Donald et al. 2002) . Many mammalian predators use tramlines to cross fields and the nests would then be easy to locate by smell.

7.4.1 Skylarks breeding on arable farmland

The skylark is a grassland bird that has taken advantage of the expansion of farmland habitats. Changes in farming over the twentieth century have decreased the availability of suitable breeding habitat for the skylark, a decline that some agri- environment schemes are attempting to rectify (Morris et al. 2004). This study backs up others in finding that skylark territory density is highest in low and sparse vegetation (Wilson et al. 1997; Wakham-Dawson et al. 1998; Chamberlain et al. 1999a; Toepfer and Stubbe 2001). Oil seed rape becomes very tall and dense early in the year and this is likely to be the reason why these fields have the lowest skylark territory densities. The highest density of skylark territories occurs in the game crop sorghum, although since only one field of sorghum was investigated this cannot be statistically confirmed. Sorghum is also found in smaller quantities at the edges of several other fields. None of the interactions between crop and season were significant, possibly due to the small sample sizes, but spring wheat, sugar beet, maize and potato fields seem to have increased numbers of skylark territories later in the season, whilst the numbers on sorghum and winter-sown wheat seem to decrease. Early in the breeding season sorghum, sugar beet, maize and potato fields are still bare but by June these crops are getting taller and/or denser, especially sorghum which grows rapidly and is densely sown. During the breeding season many pairs were observed to expand their territories to include other fields or moved to different fields. Presumably these territory shifts were to take advantage of more favourable habitats (Poulsen et al. 1998; Toepfer and Stubbe 2001).

Field boundaries in Lower Austria differ from the UK in that fewer hedgerows and more irrigation channels are found. As with previous research this study finds that skylark densities are highest on fields with lower boundaries (Wilson et al. 1997; Poulsen et al. 1998). The most prevalent boundary types at Seefeld are irrigation ditches and broken tree lines. Often a commercial crop has an area of game crop or set-aside next to it. With the exception of the more continuous tree lines these boundary types are ideal for skylarks as they allow them to utilise the whole field. Woodland field boundaries are mostly small and occur infrequently so have minimal impact on the skylarks. The average field size used in this study was 26.6 (±1.73) ha giving the skylarks a lot of open crop to utilise.

139

All the skylark nests found were in cereal crops. During the initial 2009 surveys more pairs were observed in cereal crops than other crop types leading the study to focus on these fields. Eleven skylark nests were discovered, half of which were abandoned or predated before the eggs hatched. Skylark chicks are fed a wide range of invertebrate types, nearly half of which were beetles, an order they show a preference for. Spiders and unidentifiable invertebrates made up most of the remainder of their diet. In most cases adult skylarks were observed feeding in the same field as their nests, often in more sparse patches or areas of sorghum early in the season. In one case the nest was in one field of spring barley whilst all the foraging trips observed were across a farm track to an adjacent field of winter wheat.

7.4.2 The diets of wild chicks compared with human-imprinted pheasant chicks

The chicks of various farmland birds all share the same habitat and have access to the same prey resources. It might therefore be assumed that they eat a similar range of invertebrates. This study has shown that the diets of the wild skylark and lapwing chicks differ significantly from that of the human-imprinted pheasant chicks, and also from each other. Skylark parents feed their chicks proportionally more spiders than are eaten by pheasant chicks and more Hymenoptera than are eaten by lapwing chicks. Lapwing chicks are able to forage for themselves soon after hatching as do pheasant chicks yet the lapwing chicks eat proportionally more of the group ‘Other’ than the pheasant chicks. Millipede fragments could not be analysed statistically since the number of rings (diagnostic fragment in faeces) per millipede varies considerably between individuals depending on size and species. Whilst millipedes were eaten by most lapwing broods, no evidence of them was found in the faeces of any other species investigated. This is likely to be due to some aspect of the feeding behaviour of the lapwings. Lapwings usually feed by picking invertebrates off the soil vegetation or soil but can also use their bills to probe the soil and pull out invertebrates the other species in this study cannot reach (Treweek et al. 1997; Gillings and Sutherland 2007). To investigate the relative importance of millipedes in their diet further research is needed. Since only one yellow wagtail nest was found it has been excluded from the analysis but samples from that nest show higher proportions of spiders, flies (‘Other’) and larvae, and much lower proportions of beetles than any of the other species.

140 Yellow wagtails can take prey items whilst in flight (Davies 1977), thereby allowing access to a greater range of potential prey than is available to obligate ground-feeders.

All three bird species ate more beetles than any other invertebrate group, and showed a significant preference for beetles. All three groups also showed a tendency to avoid Hemiptera and ‘Other’; this last group being mostly composed of flies. These same trends can be seen in the yellow wagtail diet but again these could not be tested statistically since only one nest was found. Interestingly, the human-imprinted pheasant chicks ate proportionally more Hemiptera than either wild skylark or lapwing chicks. This may be due to the trials being conducted in crop fields, which contain a larger number of Hemiptera, especially aphids. In arable habitats aphids make up a large proportion of the hemipteran fauna and aphids are known to be of low nutritional quality (Borg and Toft 1999; Toft 2005). Aphids, plant bugs and flies tend to be found in the higher levels of the crop whilst pheasant and lapwing chicks are ground feeders meaning that the low occurrence of these items in their diet could be due to their difficulties in catching them and not an active choice. Whilst adult skylarks may be able to take insects on the wing they were more commonly observed feeding on the ground. As it is impossible to distinguish between active choice and availability without further studies both are combined as avoidance in the study. Such combination is appropriate as both factors will strongly influence what invertebrates are eaten in the field.

The multivariate plot shows that the galliformes (including the grey partridge from Chapter 6) and passerines are divided into distinctly separate clusters. The lapwings show a more variable scatter, which overlaps with both of the other groups. This indicates that lapwing chicks have a more varied diet, possibly due to their wider foraging range as they cross different habitat types. Wild pheasant and partridge chicks are likely to have a similarly wide range since both follow their parents across several habitats whilst foraging.

One of the main problems with comparing the diets of wild and human-imprinted birds is that of foraging range. Each human-imprinted pheasant brood foraged for only 30 minutes in a comparatively small area of a single habitat type, which severely limited the range of available invertebrates. Wild birds have a larger foraging area;

141 skylarks can travel up to 300 m to find suitable foraging (Wilson et al. 1997), lapwing broods may travel around 99 m looking for suitable foraging grounds (Johansson and Blomqvist 1996) and the average range of wild pheasant broods on the Seefeld estate is 11.1 ha and falls across several different habitats (Bliss 2004). Wild broods will also have fragments from previous meals in their digestive tract (Moreby and Stoate 2000), whereas the pheasant feeding trials were designed to take a sample from a single foraging session. It is likely that lapwings use more habitats than sampled by this study since we relied on visual observations to locate the wild broods and so focused our time on those fields that allowed a view of the ground. Lapwings were observed near the river bank on a couple of occasions, but these wetland habits were too dense to allow us to survey them efficiently. Similarly, skylarks were easier to find in sparser fields and patches than denser crops.

Another problem with this methodology is that the pheasant trials took place up to 55 days after the initial wild samples were collected. Since month is known to significantly affect diet (Chapter 5) this may also explain some of the differences between the diets of the different species. Unfortunately with only two researchers it was impossible to conduct the imprinting trials whilst simultaneously searching for wild broods. The similarities in dietary preference suggest that extrapolating from the results of trials using human-imprinted pheasant chicks to wild broods of other species may be justifiable if the differences in foraging behaviours are taken into consideration.

142 8 GENERAL DISCUSSION

The findings of this study can be broken down into three distinct sections. Firstly a review of the methodology developed for the imprinting and use of pheasant chicks in field experiments. Since this has never been previously documented the successes and problems are recounted here. The main aim of this research was to determine which areas of arable habitat provide the best foraging for wild pheasant chicks, with an emphasis on set-aside areas. This part of the study spanned the full three years of field work and so provides substantial evidence of the differences in diet between chicks foraging in different habitats. Lastly the study branched out to study other species by imprinting grey partridge chicks as well as pheasants and, with the help of two MSc students, looking at the diets of some wild passerines and waders.

8.1 The methodology of using human-imprinted pheasant chicks

The imprinting of pheasants is only briefly mentioned in the literature (Kimmel 1985; Kimmel and Healy 1987; Regenscheid et al. 1987; Jalme et al. 2003) and no record of the methodology used could be found. Other Galliforme species have been successfully imprinted for use in field trials including the grey partridge (Herrmann and Fuchs 2006) in Germany and the greater sage-grouse (Huwer 2004) and northern bobwhite quail (Palmer et al. 2001; Smith and Burger 2005; Butler et al. 2007) in the USA. The methods of imprinting used for the pheasant chicks (Section 2.2) was based on the work done by Kimmel and Healy (1987) and Butler (2007; pers. comm.) and were modified based on equipment and space available and on the requirements of pheasant chicks.

The time spent imprinting the newly hatched chicks was 10 hours a day, usually between the hours of 07:00 and 19:00. Previous studies tend to imprint the chicks for longer than this with some handlers remaining with the chicks continually during the imprinting process (Huwer 2004; Herrmann and Fuchs 2006) and others continually for at least the first 12 hours (Palmer et al. 2001; Butler 2007) or during daylight hours (Kimmel and Healy 1987). This highlights the first disadvantage of using a single researcher for this type of study; continual imprinting is impossible unless it is possible to sleep with the chicks. The average imprint rate of pheasants used in this

143 study was 86.4% (measured at five days old) which was considered good, although no previous data with which to compare this could be found. Previous research does document chick loss during field trials (Huwer 2004; Butler 2007), which occurs when a chick that has not fully imprinted is taken to the field. Only 3.4% of chicks used in this study were lost in the field compared with 13.5% (Butler 2007) and 19.2% (Huwer 2004) implying that the techniques used in this study both imprint the chicks successfully and ensure that only chicks which are fully imprinted get used in field trials (allowing for a 5% error).

Bobwhite quail broods will stick together and find their own foraging path through the habitat (Palmer et al. 2001; Butler 2007) but the pheasant chicks tended to stay close to their human handler or wander off in separate directions. For this reason trials in this study chose to walk the chicks along a set transect in each habitat type, yet allowing the chicks time to wander away from that transect and forage successfully. Whether the 10 metres over 30 minutes provided an optimum coverage of the crop field could not be tested without further resources, but to cover a greater area with the youngest chicks (five days old) would not have allowed sufficient time for them to explore their surroundings. A 30 minute trial is optimal since it allows chicks to become acclimatised and forage naturally yet ensure minimal loss of diagnostic fragments in faeces in the field (Pyke 1989; Butler et al. 2004). Field trials were usually carried out between 12:00 and 18:00 with the exception of four broods used in June and July 2007 when adverse temperature during the day pushed the trials back to between 18:00 and 19:30. Ideally trials should be carried out at different times of day since invertebrate prey available may vary diurnally (Gullan and Cranston 2005) but due to the presence of a single researcher during most field trials and the lack of space for additional collection pens this would have significantly decreased the number of field trials conducted from three per day (depending on weather and the availability of an assistant) to three every other day. This would make an interesting additional study if resources were available.

The methods used in faecal collection and analysis used in this study had been previously established (Moreby 1988; Butler 2007). One problem with faecal analysis, however, is that different diagnostic fragments are digested at different rates. Interestingly, the correction factors established here (Chapter 3) are similar to those

144 found for the bobwhite quail (Butler 2007), a much smaller gamebird in a different family. These feeding trials also showed that whilst over 75% of the fragments recovered over 24 hours were recovered during the first 18 hours some of the larger items were still being found at 24 hours. Due to the time constraints imposed by a single researcher and the short window in which the chicks could be used in field trials faeces were collected after 17 hours allowing time for the droppings to be collected, stored and the collection pens thoroughly cleaned before the next chick trials commenced. Space was also limited preventing more collection pens being used.

8.2 Arable habitats beneficial to foraging pheasant broods

Many farmland birds that require high proportions of invertebrates as chicks have declined on farmland (Potts 1986; Brickle and Harper 1999; Wilson et al. 1999; Newton 2004; Winspear and Davies 2005; Holland et al. 2006). Due to the release of a large number of reared pheasant poults each year in the UK most management for this species has focused on autumn and winter habitats, neglecting the breeding season (Hill and Robertson 1988; Robertson 1997; Canning 2005). Although this release of poults masks any decline in the wild population (Hill and Robertson 1988) it is likely that the decline of invertebrate chick food has a detrimental affect on wild pheasant broods (Hill 1985; Savory 1989). This study builds on previous research in identifying those habitats of most benefit to pheasant broods in arable farmland (Warner et al. 1984; Hill 1985; Regenscheid et al. 1987; Pyke 1989; Kubišta 1990; Nelson et al. 1990; Bliss 2004; Draycott et al. 2009). Research comparing the diets of wild and commercially farmed pheasant chicks implies that the results of these trials using human-imprinted pheasant chicks may be applied to wild pheasant broods (Chapter 4).

This study found no difference in foraging potential between the different crop types, although spring sown cereals appeared denser (Chapter 5). This is contradictory to other studies that have found spring-sown crops to be more open than winter-sown crops and therefore of greater value to foraging birds, as the open structure makes it easier to gather food and provides a better view of any approaching predators (Odderskær et al. 1997; Atkinson et al. 2004; Whittingham and Evans 2004). This may be because a smaller proportion of spring-sown fields were included in the study

145 due to their low availability. Between cropped and non-cropped areas no difference was found in either the number or diversity of invertebrates eaten; however, more of their preferred groups were eaten in non-cropped areas (Chapter 5). This discrepancy may be due to the chicks actively choosing one prey item over another (Roper 1990; Mastrota and Mench 1995; Gamberale-Stille and Tullberg 2001; Moreby et al. 2006) or the fact that some prey items are easier to obtain than others (Wolda 1990). It is important to remember that the word preferred here refers simply to those groups that are found in greater proportions in the chicks’ faeces than in the field. Whilst this may not be considered ideal, its use is justified here since both choice and availability are acting on chicks foraging in the wild. A prey item may be chosen by a chick in the laboratory which is difficult to obtain in the field due to camouflage or the item being out of the chick’s reach. The abundance of such an item in the field does not make the field a good foraging ground unless it also contains easily available and nutritionally beneficial prey items.

Chicks foraging in naturally regenerated areas ate a greater proportion of these preferred groups, although chicks foraging in either area ate a high proportion of preferred prey items. The main difference is that chicks foraging in the areas of naturally regenerated set-aside ate twice as many prey items as chicks foraging in sown set-aside. Since there is no difference in invertebrate abundance between the areas it is concluded that foraging in the naturally regenerated areas is more efficient, probably due to its less dense vegetation structure (Chapter 5). Thus it appears that areas of long-term or naturally regenerated set-aside are of principal benefit to foraging pheasant broods. This supports previous research at Seefeld which found that pheasant broods favour set-aside areas (Bliss 2004) and general studies showing that when managed correctly set-aside benefits gamebirds, especially areas of permanent cover (Panek 1997; Sotherton 1998; Henderson et al. 2000).

8.3 Potential application for other species

The decline of farmland birds is due to a combination of changes driven by the intensification of farming (Chapter 1). The grey partridge and skylark have suffered especially severe declines over the latter half of the twentieth century, mostly due to different changes in farming. The grey partridge was severely affected by the

146 increased use of herbicides and insecticides which decreased the quantity of invertebrate food available (Blank et al. 1967; Southwood and Cross 1969; Potts 1986). The skylark has been strongly affected by the increased sowing of crops in autumn and the decline of spring-sown crops. This, combined with the increased use of fertiliser, has led to a very dense crop structure earlier in the year, which is unsuitable for skylark foraging (Chamberlain et al. 1999a; Donald et al. 2001a; Toepfer and Stubbe 2001). Whilst these are the main changes affecting populations, the decline of suitable habitats and food availability has affected all farmland bird species to varying degrees (O'Connor and Shrubb 1986; Siriwardena et al. 1998; Krebs et al. 1999; Winspear and Davies 2005).

The diets of grey partridge, skylark, lapwing and yellow wagtail chicks were investigated at Seefeld to determine whether those habitats beneficial to pheasant broods might also support other farmland birds. Human-imprinted grey partridge chicks ate the same invertebrates as human-imprinted pheasant chicks, although being smaller they ate fewer invertebrates (Chapter 6). Wild skylark, lapwing and yellow wagtail broods ate fewer invertebrates than the human-imprinted pheasant chicks but this may be due to fewer faeces being collected from wild birds. The wild chicks ate a greater proportion of spiders and flies and fewer true bugs than the human-imprinted pheasant chicks. The diets of wild skylarks and lapwings also differ significantly from each other with the lapwings eating proportionally more ants and fewer spiders (Chapter 7). There are some similarities in dietary preference between all the species studied; all prefer beetles and avoid true bugs and flies. The grey partridge and pheasant also prefer Hymenoptera whilst skylarks tend to avoid them. Previous research found that Coleoptera are the most important invertebrates for the majority of farmland bird species (Holland et al. 2006) which is supported by this study which found Coleoptera making up over 47% of the diet of all species studied (excluding the yellow wagtail since only one brood was sampled). Previous reviews have also found Hemiptera (especially aphids), Lepidoptera and Diptera larvae, Hymenoptera (especially ants and sawflies) and spiders to be of particular importance to several groups of farmland birds (Wilson et al. 1999; Holland et al. 2006); these groups combined make up over 70% of the diets of all species here studied. These dietary similarities mean that areas benefiting the imprinted-pheasant chicks are likely to benefit other farmland bird species, especially other gamebirds.

147

Skylark density on the arable land at Seefeld (Chapter 7) is comparable with that in the UK (Chamberlain et al. 1999a; Browne et al. 2000) and similarly territory densities are highest in short vegetation and in fields with low boundaries (Wilson et al. 1997; Poulsen et al. 1998; Wakham-Dawson et al. 1998; Chamberlain et al. 1999a; Toepfer and Stubbe 2001). Previous studies of skylarks have found that set-aside areas can be beneficial (Poulsen et al. 1998; Chamberlain et al. 1999a; Browne et al. 2000) as they can support higher densities. Higher numbers may still be found in crop fields simply because they cover a greater area (Browne et al. 2000). This highlights a problem with many existing AES, which provide a high quality habitat but only over a small area (Vickery et al. 2004). This can be detrimental as it may increase predation rates, possibly through density-dependent effects (Donald et al. 2002; Bro et al. 2004). To be of greatest benefit to farmland birds AES need to be targeted at the crop fields themselves (Butler et al. 2007).

Set-aside areas, especially those of permanent cover, are also important to grey partridges, providing more food and leading to increased survival rates (Panek 1997; Kaiser et al. 2006). Lapwings have also been shown to prefer areas of set-aside (Wilson et al. 2001) as have other farmland birds (Vickery et al. 2004; Berg and Kvarnbäck 2005; Bracken and Bolger 2006; Vickery et al. 2009) and mammals (MacDonald et al. 2007). Plant diversity and abundance is higher in areas of long- term set-aside than in adjacent crop fields and tends to increase over time with community succession (Corbet 1995; Steffan-Dewenter and Tscharntke 1997; Van Buskirk and Willi 2004). Invertebrate abundance and diversity is also higher in set- aside areas, possibly due to the rich plant life (Corbet 1995; Steffan-Dewenter and Tscharntke 1997; Steffan-Dewenter and Tscharntke 2001; Van Buskirk and Willi 2004). In sown areas of set-aside the seed mix will affect the plant diversity and through this the invertebrate communities (Meek et al. 2002; Carvell et al. 2007; Smith et al. 2008a).

This study helps highlight the importance of vegetation structure in determining foraging behaviour and success. Previous studies have shown that a more open vegetation structure is preferred by ground-feeding birds, even if it contains fewer invertebrates (Odderskær et al. 1997; Atkinson et al. 2004; Morris et al. 2004).

148 Shorter, sparser vegetation may affect the foraging birds in two ways, either by increasing foraging efficiency or by reducing the perceived predation risk (Whittingham and Evans 2004). In shorter vegetation birds will be able to see further, allowing greater detection of prey. Sparser vegetation will allow greater movement, allowing more efficient foraging (Butler and Gillings 2004). Shorter vegetation is also likely to decrease perceived predation risk for ground-feeding birds as it will allow them to see any approaching predators (Metcalfe 1984; Whittingham et al. 2004; Whittingham and Evans 2004). This is contrary to the responses of small mammals which tend to avoid open habitats and have a lower predation risk in dense cover (Kotler et al. 1991; Longland and Price 1991; Hurst et al. 2003). This difference is likely to be due to the different escape mechanisms of mammals and birds; birds have the ability to escape more rapidly, and in a three-dimensional environment, by flying to the safety of denser cover (Whittingham and Evans 2004). The perceived predation risk will also vary with different types of cover. Very dense cover will obstruct the view of any approaching predator, whereas patchy cover can be seen as beneficial as it provides protective shelter and gives minimal visual obstruction of predators (Lazarus and Symonds 1992). Whilst most birds respond to a predator by flight the first response of many gamebirds, including the grey partridge and pheasant, and some others, such as the corncrake, is to remain low and stationary and rely on their cryptic plumage (Whittingham and Evans 2004). For these birds it is best to provide some within field patches of slightly taller vegetation.

8.4 Managment suggestions

This study suggests that in order to improve the survival of wild pheasant broods in arable farmland it is important to include significant areas of non-crop habitat. Ideally these areas should not just be narrow strips at the edges of crops as these areas can attract predators (Robertson 1997; Donald et al. 2002; Bro et al. 2004). Areas of longer term set-aside are especially important as they provide a natural moasic of grasses and forbs which provide an ideal matrix for foraging chicks as they provide access to many beneficial insects whilst also providing denser patches of cover. These areas should be managed at a low level outside of the breeding season to prevent them developing into denser scrub. Where game crops are planted care should be taken to ensure they are not sown too densely as very dense habitats can impede chick

149 movement and retain rain water longer which can cause chilling to chicks (Offerdahl and Fivizzani 1987; Robertson 1997). Alternatively sow areas of varying density if denser patches are required, for over-winter cover for example. To encourage landowners to include such areas AES should put additional value on larger areas of land being kept out of cultivation.

8.5 Further research

It would be interesting to look at the diets of the pheasants foraging in different habitats in terms of invertebrate size as well as taxonomic diversity. This option was considered during the project but was deemed too time consuming for a single researcher. A rough comparison of sizes was made during laboratory work and any differences observed were considered to be negligible making it unnecessary for further investigation considering the time available. It may be that by repeating the study in other habitats prey size may be an important factor.

Further research on prey preference in a laboratory setting would be ideal. Previous studies have shown that some level of selection occurs in that aposematic colours are avoided (Roper 1990; Mastrota and Mench 1995; Gamberale-Stille and Tullberg 2001; Moreby et al. 2006). Some previous research on self-selection of prey items has been done in the laboratory (Borg and Toft 2000) and it would be interesting to replicate this with a wider choice of potential prey items. It would also be interesting to produce a three-dimensional feeding environment in the laboratory to test how vegetation structure and the positioning of prey items affect choice.

It would be useful to study the diets of wild and imprinted chicks simultaneously using radio-tracking studies. Due to financial reasons this could not be pursued here but it would allow an accurate comparison of wild and imprinted chicks foraging on the same habitat. Simultaneous study of the imprinted gamebirds and other wild bird species would help confirm the findings of Chapter 7. If field assistants were available it would be interesting to increase the number of wild birds (sample size and species) studied to determine similarities between their diets.

150 To be of greater use this study could be replicated in different habitats and locations to build a fully comprehensive view of the foraging potential of different management options. Extending the emphasis on chick behaviour and movement would also help identify the optimum vegetation structure required by brood-rearing cover (Robertson 1997; Dwyer 1999). It would also be interesting to repeat these methods on different AES prescriptions to further our understanding of how these will affect farmland birds (Sotherton and Robertson 1990; Henderson et al. 2000; Vickery et al. 2002; Marshall et al. 2006).

8.6 Conclusions

Set-aside areas, especially those which are allowed to regenerate naturally over time, can provide an important habitat for foraging pheasant broods. To provide a good foraging habitat, set-aside must have a sufficiently open vegetative structure to allow easy movement and prey detection. Sown areas of game crop or flower strips also hold invertebrate prey in high abundances but will not be used by birds if their vegetation is too dense (Sotherton 1998; Winspear and Davies 2005; Cole et al. 2007). Sowing game crops at a lower density will increase their suitability as foraging habitats. These areas will also benefit other farmland birds, particularly other gamebirds, but set-aside areas alone will not halt or reverse the decline of farmland bird populations, since set-aside areas only cover a small percentage of farmland. There is hope for a more environmentally friendly, post-industrial era of farming (Buckwell and Armstrong-Brown 2004) with AES helping to preserve some non- cropped areas, especially field margins. Creating or maintaining large areas of set- aside and preventing vegetative succession on long-term areas will also increase their benefits to game and other farmland birds. In order to support a high diversity of farmland birds it is important to maintain habitat heterogeneity at a landscape scale with a mixture of in-field and field margin prescriptions.

151 9. REFERENCES

Aebischer, N. J. and P. A. Robertson (1993). Compositional analysis of habitat use from animal radio-tracking data. Ecology 74 : 1313-1325. Ahnström, J., Å. Berg and H. Söderlund (2008). Birds on farmsteads - effects of landscape and farming characteristics. Ornis Fennica 85 : 98-108. Ai, H.-s. (2006). Pheasant Diversity and Conservation in the Mt. Gaoligongshan Region. Zoological Research 27 : 427-432. Anderson, B. C. (2002). Habitat use and nesting ecology of ring-necked pheasant (Phasianus colchicus ) on a landscape dominated by agriculture in Lower Austria. Warnell School of Forest Resources . Athens, Georgia, The University of Georgia. MSc thesis . Anon (1999). Europe’s Agenda 2000: strengthening and widening the European Union . European Commission, Brussels. Anon. (2006). Large Physical Map of Austria . Code Network Media Group. Retrieved 14/07/2009, from http://www.maps-of-austria.co.uk/large-physical- austria-map.htm . Anon. (2007). Report on the Species and Habitat Review . UK Biodiversity Action Plan. Retrieved 03/12/2009, from http://www.ukbap.org.uk . Anon (2008). Entry Level Stewardship Handbook, Natural England : pp.28-83. Anon. (2009). Environmental Stewardship . Natural England. Retrieved 19/11/2009, from http://www.naturalengland.gov.uk/ourwork/farming/funding/es/default.aspx . Atkinson, P. W., D. Buckingham and A. J. Morris (2004). What factors determine where invertebrate-feeding birds forage in dry agricultural grasslands? Ibis 146 : 99-107. Ausden, M. and G. J. M. Hirons (2002). Grassland nature reserves for breeding wading birds in England and the implications for the ESA agri-environment scheme. Biological Conservation 106 : 279-291. Banks, C. J. and E. S. Brown (1962). A comparison of methods of estimating population density of adult sunn pest, Eurygaster integriceps Put. (Hemiptera, Scutelleridae) in wheat fields. Entomologia Experimentalis et Applicata 5: 255-260.

152 Bartram, H. and A. Perkins (2003). The biodiversity benefits of organic farming. Organic agriculture: sustainability, markets, and policies . O. f. E. C.-o. a. Development. Wallingford, CABI Publishing : 77-93. Bechinski, E. J. and L. P. Pedigo (1982). Evaluation of methods for sampling predatory arthropods in soybeans. Environmental Entomology 11 : 756-761. Beecher, W. J. (1951). Adaptations for food getting in the American blackbirds. Auk 68 : 411-440. Berg, Å. and O. Kvarnbäck (2005). Preferences for different arable field types among breeding farmland birds - a review. Ornis Svecica 15 : 31-42. Blank, T. H., T. R. E. Southwood and D. J. Cross (1967). The ecology of the partridge: I. Outline of population processes with particular reference to chick mortality and nest density. Journal of Animal Ecology 36 : 549-556. Bliss, T. H. (2004). Habitat requirements of ring-necked pheasant hens ( Phasianus colchicus ) on farmland in Lower Austria during nesting and brood rearing. Warnell School of Forestry Resources . Athens, Georgia, University of Georgia. MSc thesis . Bliss, T. H., B. C. Anderson, R. A. H. Draycott and J. P. Carroll (2006). Survival and habitat use of wild pheasant broods on farmland in Lower Austria . Gamebird 2006: Quail VI and Perdix XII, Warnell School of Forestry and Natural Resources, Athens, GA, USA. Blomqvist, D. and O. C. Johansson (1995). Trade-offs in nest site selection in coastal populations of lapwings Vanellus vanellus . Ibis 137 : 550-558. Boag, B. and S. Tapper (1992). The history of some British gamebirds and mammals in relation to agricultural change. Agricultural Zoology Reviews 5: 273-311. Boatman, N. D., N. W. Brickle, J. D. Hart, T. P. Milsom, A. J. Morris, A. W. A. Murray, K. A. Murray and P. A. Robertson (2004). Evidence for the indirect effects of pesticides on farmland birds. Ibis 146 : 131-143. Bolton, M., G. Tyler, K. Smith and R. Bamford (2007). The impact of predator control on lapwing Vanellus vanellus breeding success on wet grassland nature reserves. Journal of Applied Ecology 44 : 534-544. Borg, C. and S. Toft (1999). Value of the aphid Rhopalosiphum padi as food for grey partridge Perdix perdix chicks. Wildlife Biology 5: 55-58.

153 Borg, C. and S. Toft (2000). Importance of insect prey quality for grey partridge chicks Perdix perdix : a self-selection experiment. Journal of Applied Ecology 37: 557-563. Bourassa, S., H. A. Cárcamo, F. J. Larney and J. R. Spence (2008). Carabid assemblages (Coleoptera: Carabidae) in a rotation of three different crops in Southern Alberta, Canada: A comparison of sustainable and conventional farming. Environmental Entomology 37 : 1214-1223. Bracken, F. and T. Bolger (2006). Effects of set-aside management on birds breeding in lowland Ireland. Agriculture, Ecosystems and the Environment 117 : 178- 184. Brickle, N. W. and D. G. C. Harper (1999). Diet of nestling corn buntings Miliaria calandra in southern England examined by compositional analysis. Bird Study 46 : 319-329. Bro, E., P. Mayot, E. Corda and F. Reitz (2004). Impact of habitat management on grey partridge populations: assessing wildlife cover using a multisite BACI experiment. Journal of Applied Ecology 41 : 846-857. Browne, S., J. Vickery and D. E. Chamberlain (2000). Densities and population estimates of breeding Skylarks Alauda arvensis in Britain in 1997. Bird Study 47 : 52-65. Browne, S. J., N. J. Aebischer, S. J. Moreby and L. Teague (2006). The diet and disease susceptibility of grey partridges Perdix perdix on arable farmland in East Anglia, England. Wildlife Biology 12 : 3-10. Bryant, D. M. (1973). The factors influencing the selection of food by the House Martin ( Delichon urbica (L.)). Journal of Animal Ecology 42 : 539-564. BTO. (2006). England Biodiversity Strategy Indicators . Retrieved 19/01/2010, from http://www.bto.org/research/indicators/england_indicators.htm . Buckwell, A. and S. Armstrong-Brown (2004). Changes in farming & future prospects - technology and policy. Ibis 146 : 14-21. Buffington, M. L. and R. A. Redak (1998). A comparison of vacuum sampling versus sweep-netting for arthropod biodiversity measurements in California coastal sage scrub Journal of Insect Conservation 2: 99-106. Buller, H., G. A. Wilson and A. Höll (2000). Agri-environmental policy in the European Union . Aldershot, Ashgate Publishing Ltd.

154 Butler, D. A. (2007). The role of invertebrates in the diet, growth and survival of northern bobwhite, Colinus virginianus , chicks in the southeastern United States. Liverpool, Liverpool John Moores University. PhD thesis: 220. Butler, D. A., W. E. Palmer and S. D. Dowell (2004). Passage of arthropod-diagnostic fragments in Northern Bobwhite chicks. Journal of Field Ornithology 74 : 372- 375. Butler, S. J. and S. Gillings (2004). Quantifying the effects of habitat structure on prey detectability and accessibility to farmland birds. Ibis 146 : 123-130. Butler, S. J., J. A. Vickery and K. Norris (2007). Farmland biodiversity and the footprint of agriculture. Science 315 : 381-384. Cadbury, C. J. (1980). The status and habitats of the Corncrake in Britain 1978–79 Bird Study 27 : 203-218. Canning, P. (2005). The UK game bird industry - A short study . Lincoln, ADAS, commissioned by DEFRA. Carvell, C., W. R. Meek, R. F. Pywell and D. Goulson (2007). Comparing the efficacy of agri-environment schemes to enchance bumble bee abundance and diversity on arable field margins. Journal of Applied Ecology 44 : 29-40. Chamberlain, D. E. and H. Q. P. Crick (1999). Population declines and reproductive performance of Skylarks Alauda arvensis in different regions and habitats of the United Kingdom. Ibis 141 : 38-51. Chamberlain, D. E. and R. J. Fuller (2001). Contrasting patterns of change in the distribution and abundance of farmland birds in relation to farming system in lowland Britain. Global Ecology and Biogeography 10 : 399-409. Chamberlain, D. E., R. J. Fuller, R. G. H. Bunce, J. C. Duckworth and M. Shrub (2000). Changes in the abundance of farmland birds in relation to the timing of agricultural intensification in England and Wales. Journal of Applied Ecology 37 : 771-788. Chamberlain, D. E., A. M. Wilson, S. J. Browne and J. A. Vickery (1999a). Effects of habitat type and management on the abundance of skylarks in the breeding season. Journal of Applied Ecology 36 : 856-870. Chamberlain, D. E., J. D. Wilson and R. J. Fuller (1999b). A comparison of bird populations on organic and conventional farm systems in southern Britain. Biological Conservation 88 : 307-320.

155 Chinery, M. (1993). Insects of Britain and Northern Europe , Harper Collins Publishers, London. Chiverton, P. A. (1999). The benefits of unsprayed cereal crop margins to grey partridges Perdix perdix and pheasants Phasianus colchicus in Sweden. Wildlife Biology 5: 83-92. CIA. (2009). The World Factbook 2009 . Central Intelligence Agency. Retrieved 20/11/2009, from https:// www.cia.gov/cia/publications/factbook/geos/xx.html . Clarke, J. H., S. K. Cook, D. Harris, J. J. J. Wiltshire, I. G. Henderson, N. E. Jones, N. D. Boatman, S. G. Potts, D. B. Westbury, B. A. Woodcock, A. J. Ramsay, R. F. Pywell, P. E. Goldsworthy, J. M. Holland, B. M. Smith, J. Tipples, A. J. Morris, P. Chapman and P. Edwards (2007). The SAFFIE Project Report . ADAS, Boxworth. Cole, L. J., D. I. McCracken, L. Baker and D. Parish (2007). Grassland conservation headlands: Their impact on invertebrate assemblages in intensively managed grassland. Agriculture, Ecosystems and Environment 122 : 252-258. Cooper, R. J. and R. C. Whitmore (1990). Arthropod sampling methods in ornithology. Studies in Avian Biology 13 : 29-37. Corbet, S. A. (1995). Insects, plants and succession: advantages of long-term set-aside. Agriculture, Ecosystems and Environment 53 : 201-217. Corbit, M., P. L. Marks and S. Gardescu (1999). Hedgerows as habitat corridors for forest herbs in central New York, USA. Journal of Ecology 87 : 220-232. Costa, E. C. and E. Corseuil (1979). Assessment of the efficiency of five methods for sampling arthropods associated with soyabean crops. Revista do Centro de Ciencias 9: 81-93. Cross, D. J. (1966). Approaches toward an assessment of the role of insect food in the ecology of game-birds, especially the Partridge ( Perdix perdix ). London, University of London : 235. Cruz-Rivera, E. and M. E. Hay (2000). Can quantity replace quality? Food choice, compensatory feeding, and fitness of marine mesograzers. Ecology 81 : 201- 219. Cummins, S. and J. O'Halloran (2002). An assessment of the diet of nestling stonechats Saxicola torquata using compositional analysis. Bird Study 49 : 139-145.

156 Custer, T. W. and F. A. Pitelka (1974). Correction factors for digestion rates for prey taken by snow buntings ( Plectrophenax nivalis ). The Condor 77 : 210-212. Dahlgren, J. (1990). The significance of arthropods in the grey partridge diet . Perdix V: Grey Partridge Workshop, Kansas Department of Wildlife and Parks, Emporia. Davey, P. and N. Aebischer (2008). National gamebag census: game species trends. Game and Wildlife Conservation Trust: Review of 2007 . 39: 30-33. Davies, N. B. (1976). Food, flocking and territorial behaviour of the Pied Wagtail (Motacilla alba yarrellii Gould) in winter. Journal of Animal Ecology 45 : 235- 253. Davies, N. B. (1977). Prey selection and social behaviour in wagtails (Aves: Motocillidae). Journal of Animal Ecology 46 : 37-57. de Ruiter, L. (1952). Some experiments on the camouflage of stick caterpillars. Behaviour 4: 222-232. DEFRA (2009a). Agricultural Statistics in your Pocket 2008 . Farming Statistics, Accounts and Publications, Department for Environment, Food and Rural Affairs, York. DEFRA. (2009b). Farming: Single Payment Scheme . Department for Environment, Food and Rural Affairs. Retrieved 19/11/2009, from http://www.defra.gov.uk/foodfarm/farmmanage/singlepay/index.htm . DEFRA (2009c). UK biodiversity indicators in your pocket 2009: measuring progress towards halting biodiversity loss . Department for Environment, Food and Rural Affairs, London. Diamond, J. (1991). A new species of rail from the Solomon Islands and convergent evolution of insular flightlessness. Auk 108 : 461-470. Donald, P. F., A. D. Evans, D. L. Buckingham, L. B. Muirhead and J. D. Wilson (2001a). Factors affecting the territory distribution of Skylarks Alauda arvensis breeding on lowland farmland. Bird Study 48 : 271-278. Donald, P. F., A. D. Evans, L. B. Muirhead, D. L. Buckingham, W. B. Kirby and S. I. A. Schmitt (2002). Survival rates, causes of failure and productivity of Skylark Alauda arvensis nests on lowland farmland. Ibis 144 : 652-664. Donald, P. F., R. E. Green and M. F. Heath (2001b). Agricultural intensification and the collapse of Europe's farmland bird populations. Proceedings of the Royal Society B: Biological Sciences 268 : 25-29.

157 Donald, P. F., F. J. Sanderson, I. J. Burfield and F. P. J. van Bommel (2006). Further evidence of continent-wide impacts of agricultural intensification on European farmland birds, 1990 - 2000. Agriculture, Ecosystems and Environment 116 : 189-196. Dowell, S. D. (1990). Differential behavior and survival of hand-reared and wild gray partridge in the United Kingdom . Perdix V: Grey Partridge Workshop, Kansas Department of Wildlife and Parks, Emporia. Drake, V. A. (1994). The influence of weather and climate on agriculturally important insects: an Australian perspective. Australian Journal of Agricultural Research 45 : 487-509. Draycott, R. A. H., T. H. Bliss, J. P. Carroll and K. Pock (2009). Provision of brood- rearing cover on agricultural land to increase survival of wild ring-necked pheasant Phasianus colchicus broods at Seefeld Estate, Lower Austria, Austria. Conservation Evidence 6: 6-10. Draycott, R. A. H., A. N. Hoodless, M. N. Ludiman and P. A. Robertson (1998). Effects of spring feeding on body condition of captive-reared ring-necked pheasants in Great BritainManagement 1998. Journal of Wildlife Management 62 : 557-563. Draycott, R. A. H., K. Pock and J. P. Carroll (2002). Sustainable management of a wild pheasant population in Austria. Zeitschrift für Jagdwissenschaft 48 : 346- 353. Durães, R. and M. Â. Marini (2003). An evaluation of the use of tartar emetic in the study of bird diets in the Atlantic Forest of southeastern Brazil. Journal of Field Ornithology 74 : 270-280. Dwyer, M. J. (1999). A study investigating the suitability of a range of annual monocultures, perennial crops, and non-rotational set-aside, as brood-rearing cover for wild gamebird chicks in lowland Britain. Centre for Environmental Technology . London, Imperial College of Science, Technology and Medicine (University of London). MSc thesis . Dyrcz, A. and H. Flinks (2003). Nestling food of the congeneric and sympatric Rusty- margined and Social flycatchers. Journal of Field Ornithology 74 : 157-165. Eaton, M. and R. Bradbury (2003). Predicting the Response of Farmland Birds to Agricultural Change: Review of species-specific and generic resource

158 requirements . Royal Society for the Protection of Birds and Department for the Environment, Food and Rural Affairs, Sandy. 44. EBCC (2000). European bird populations: estimates and trends . Cambridge, BirdLife International (with the European Bird Concensus Council). Edminster, F. C. (1954). American game birds of field and forest: their habits, ecology and management . New York, Charles Scribner's Sons. Egger, H., H. G. Kenmayr, G. W. Mandl, A. Matura, A. Nowotny, G. Pascher, G. Pestal, J. Pistotnik, M. Rockenschaub and W. Schnabel. (1999). Geological Map of Austria . Geologische Bundesanstalt. Retrieved 12/0/2010, from http://www.geologie.ac.at/pdf/Uebersichtskarten/GeolKarteAUT-eng-20.pdf . Europa. (2007, 26 September 2007). Cereals: Council approves zero set-aside rate for autumn 2007 and spring 2008 sowings . (Rapid Press Release 26 September 2007) European Union. Retrieved [Accessed: 18/02/2008], from http://europa.eu/rapid/pressReleasesAction.do?reference=IP/07/1402&format= HTML&aged=1&language=EN&guiLanguage=en . Ewald, J. A. and N. J. Aebischer (2000). Trends in pesticide use and efficacy during 26 years of changing agriculture in southern England. Environmental Monitoring and Assessment 64 : 493-529. Fenton, F. A. and D. E. Howell (1957). A comparison of five methods of sampling alfalfa fields for arthropod populations. Annals of the Entomological Society of America 50 : 606-611. Field, R. H. and G. Q. A. Anderson (2004). Habitat use by breeding Tree sparrows Passer montanus . Ibis 146 : 60-68. Firbank, L. G., S. Petit, S. Smart, A. Blain and R. J. Fuller (2008). Assessing the impacts of agricultural intensification on biodiversity: a British perspective. Philosophical Transactions of the Royal Society B 363 : 777-787. Ford, J., H. Chitty and A. D. Middleton (1938). The food of partridge chicks ( Perdix perdix ) in Great Britain. Journal of Animal Ecology 7: 251-265. Forman, R. T. T. and J. Baudry (1984). Hedges and hedgerow networks in landscape ecology. Environmental Management 8: 495-510. Fry, M. D. (1995). Reproductive effects in birds exposed to pesticides and industrial chemicals. Environmental Health Perspectives 103 : 165-171.

159 Fuller, R. J., R. D. Gregory, D. W. Gibbons, J. H. Marchant, J. D. Wilson, S. R. Baillie and N. Carter (1995). Population declines and range contractions among lowland farmland birds in Britain. Conservation Biology 9: 1435-1441. Gabriel, D. and T. Tscharntke (2007). Insect pollinated plants benefit from organic farming. Agriculture, Ecosystems and the Environment 118 : 43-48. Galbraith, H. (1988). Effects of agriculture on the breeding of lapwings Vanellus vanellus . Journal of Applied Ecology 25 : 487-503. Gamberale-Stille, G. and B. S. Tullberg (2001). Fruit or aposematic insect? Context- dependent colour preferences in domestic chicks. Proceedings of the Royal Society B: Biological Sciences 268 : 2525-2529. Gdowska, E., A. Górecki and J. Weiner (1993). Development of thermoregulation in the Pheasant Phasianus colchicus . Comparative Biochemistry and Physiology 105A : 231-234. Gillings, S. (2004). Prey detectability: significance and measurement using a novel laser pen technique. Wader Study Group Bulletin 103 : 50-55. Gillings, S., S. E. Newson, D. G. Nobel and J. A. Vickery (2005). Winter availability of cereal stubbles attracts declining farmland birds and positively influences breeding population trends. Proceedings of the Royal Society B: Biological Sciences 272 : 733-739. Gillings, S. and W. J. Sutherland (2007). Comparative diurnal and nocturnal diet and foraging in Eurasian Golden Plovers Pluvialis apricaria and Northern Lapwings Vanellus vanellus wintering on arable farmland. Ardea 95 : 243-257. Gillott, C. (1995). Entomology . New York, Plenum Press. Gilroy, J. J., G. Q. A. Anderson, P. V. Grice, J. A. Vickery, I. Bray, N. Watts and W. J. Sutherland (2008). Could soil degredation contribute to farmland bird declines? Links between soil penetrability and the abundance of yellow wagtails Motacilla flava in arable fields. Biological Conservation 141 : 3116-3126. Gionfriddo, J. P., L. B. Best and B. J. Giesler (1995). A saline-flushing technique for determining the diet of seed-eating birds. Auk 112 : 780-782. Green, R. E. (1984). The feeding ecology and survival of partridge chicks ( Alectoris rufa and Perdix perdix ) on arable farmland in East Anglia. Journal of Applied Ecology 21 : 817-830.

160 Green, R. E. (1988). Effects of environmetnal factors on the timing and success of breeding of common snipe Gallinago gallinago (Aves: Scolopacidae). Journal of Applied Ecology 25 : 79-93. Green, R. E., G. J. M. Hirons and B. H. Cresswell (1990). Foraging habitats of female common snipe Gallinago gallinago during the incubation period. Journal of Applied Ecology 27 : 325-335. Green, R. E. and G. A. Tyler (1989). Determination of the diet of the stone curlew (Burhinus oedienemus ) by faecal analysis. Journal of Zoology, London 217 : 311-320. Gregory, J. T. (1951). Convergent evolution: the jaws of Hesperonis and the mosasaurs. Evolution 5: 345-354. Gregory, R. D., D. G. Noble and J. Custance (2004). The state of play of farmland birds: population trends and conservation status of lowland farmland birds in the United Kingdom. Ibis 146 : 1-13. Gullan, P. J. and P. S. Cranston (2005). The Insects: An Outline of Entomology . Oxford, Blackwell Publishing. Harper, A. M., B. D. Schaber, T. Entz and T. P. Story (1993). Assessment of sweepnet and suction sampling for evaluating pest insect populations in hay alfalfa. Journal of the Entomological Society of British Columbia 90 : 66-76. Hartley, L., C. O'Connor, J. Waas and L. Matthews (1999). Colour preferences in North Island robins ( Petroica australis ): implications for deterring birds from poison baits. New Zealand Journal of Ecology 23 : 255-259. Hassall, M., A. Hawthorne, M. Maudsley, P. White and C. Cardwell (1992). Effects of headland management on invertebrate communities in cereal fields Agriculture, Ecosystems and the Environment 40 : 155-178. Heinrich, B. (1979). Foraging strategies of caterpillars. Oecologia 42 : 325-337. Heinz, G. (1973). Responses of ring-necked pheasant chicks ( Phasianus colchicus ) to conspecific calls. Animal Behaviour 21 : 1-9. Heinzel, H., R. Fitter and J. Parslow (1995). Birds of Britain and Europe with North Africa and the Middle East . London, HarperCollins Publishers. Henderson, I. G., J. Cooper, R. J. Fuller and J. Vickery (2000). The relative abundance of birds on set-aside and neighbouring fields in summer. Journal of Applied Ecology 37 : 335-347.

161 Henderson, I. G., N. Ravenscroft, G. Smith and S. Holloway (2009). Effects of crop diversification and low pesticide inputs on bird populations on arable land. Agriculture, Ecosystems and Environment 129 : 149-156. Herrmann, M. and S. Fuchs (2006). Grey Partridge Perdix perdix . Nature Conservation in Agricultural Ecosystems . M. Flade, H. Plachter, R. Schmidt and A. Werner, Quelle & Meyer Verlag : 183-194. Hess, C. A. (1997). Stomach flushing: sampling the diet of red-cockaded woodpeckers. Wilson Bulletin 109 : 535-539. Hill, D. and P. Robertson (1988). The Pheasant: Ecology, Management and Conservation . Oxford, Blackwell Scientific Publications Ltd. Hill, D. A. (1985). The feeding ecology and survival of pheasant chicks on arable farmland. Journal of Applied Ecology 22 : 645-654. Holland, J. M., M. A. S. Hutchison, B. Smith and N. J. Aebischer (2006). A review of invertebrates and seed-bearing plants as food for farmland birds in Europe. Annals of Applied Biology 148 : 49-71. Hurst, J. L., S. J. Gray and S. P. Jensen (2003). How does habitat structure affect activity and use of space among house mice? Animal Behaviour 66 : 239-250. Hutto, R. L. (1990). Measuring the availability of food resources. Studies in Avian Biology 13 : 20-28. Huwer, S. L. (2004). Evaluating greater sage-grouse brood habitat using human- imprinted chicks. Fort Collins, Colorado, Colorado State University : 85. IBRD. (2009). World Development Indicators . International Bank for Reconstruction and Development (The World Bank). Retrieved 20/11/2010, from http://go.worldbank.org/E8VV4M1E10 . Ihaka, R. and R. Gentleman (1996). R: A language for data analysis and graphics. Journal of Computational and Graphical Statistics 5: 299-314. Ipek, A., A. Karabulut and B. Yilmaz-Dikmen (2006). The effects of storage period on hatching characteristics of pheasant (Phasianus colchicus) eggs . EPC 2006 - 12th European Poultry Conference, Verona, Italy, World's Poultry Science Association (WPSA). IUCN. (2009). IUCN Red List of Threatened Species, (Version 2009.2) . Retrieved 08/01/2009, from http://www.iucnredlist.org .

162 Jalme, M. S., R. Lecoqa, F. Seigneurinb, E. Blesboisb and E. Plouzeau (2003). Cryopreservation of semen from endangered pheasants: the first step towards a cryobank for endangered avian species. Theriogenology 59 : 875-888. Jenni, L., P. Reutimann and S. Jenni-Eiermann (1990). Recognizability of different food types in faeces and in alimentary flushes of Sylvia warblers. Ibis 132 : 445-453. Johansson, O. C. and D. Blomqvist (1996). Habitat selection and diet of lapwing Vanellus vanellus chicks on coastal farmland in S.W. Sweden. Journal of Applied Ecology 33 : 1030-1040. Johnson, E. J., L. B. Best and P. A. Heagy (1980). Food sampling biases associated with the "ligature method". Condor 82 : 186-192. Kaiser, W., I. Storch and J. P. Carroll (2006). Habitat use and survival of grey partridge pairs in Bavaria, Germany . Gamebird 2006: Quail VI and Perdix XII, Warnell School of Forestry and Natural Resources, GA, Athens, USA. Karasov, W. H. (1996). Digestive plasticity in avian energetics and feeding ecology. Avian energetics and nutritional ecology . C. Carey. New York, Chapman and Hall. Kimmel, R. O. (1985). Attracting broods with tape-recorded chick calls. Minnesota Wildlife Report 1: 8pp. Kimmel, R. O. (1990). Behavioral relationships of gray partridge and ring-necked pheasants in mixed-species broods . Perdix V: Grey Partridge Workshop, Kansas Department of Wildlife and Parks, Emporia. Kimmel, R. O. and W. M. Healy (1987). Imprinting: A technique for wildlife research . Perdix IV: Grey Partridge Workshop, Minnesota Department of Natural Resources, Madelia. Kishimoto-Yamada, K., T. Itioka, S. Sakai, K. Momose, T. Nagamitsu, H. Kaliang, P. Meleng, L. Chong, A. Hamid Karim, S. Yamane, M. Kato, C. Reid, T. Nakashizuka and T. Inoue (2009). Population fluctuations of light-attracted chrysomelid beetles in relation to supra-annual environmental changes on a Bornean rainforest. Bulletin of Entomological Research 99 : 217-227. Kleijn, D. and L. A. C. van der Voort (1997). Conservation headlands for rare arable weeds: The effects of fertilizer application and light penetration on plant growth Biological Conservation 81 : 57-67.

163 Klein, D., R. A. Baquero, Y. Clough, M. Díaz, J. De Esteban, F. Fernández, D. Gabriel, F. Herzog, A. Holzschuh, R. Jöhl, E. Knop, A. Kruess, E. J. P. Marshall, I. Steffan-Dewenter, T. Tscharntke, J. Verhulst, T. M. West and J. L. Yela (2006). Mixed biodiversity benefits of agri-environment schemes in five European countries. Ecology Letters 9: 243-254. Klein, D. and W. J. Sutherland (2003). How effective are European agri-environment schemes in conserving and promoting biodiversity? Journal of Applied Ecology 40 : 947-969. Kotler, B. P., J. S. Brown and O. Hasson (1991). Affecting gerbil foraging behavior and rates of owl predation. Ecology 72 : 2249-2260. Ko żuszek, R., H. Kontecka, S. Nowaczewski and A. Rosi ński (2009). Storage time and eggshell colour of pheasant eggs vs. the number of blastodermal cells and hatchability results. Folia Biologica 57 : 121-130. Krebs, J. R., J. D. Wilson, R. B. Bradbury and G. M. Siriwardena (1999). The second silent spring? Nature 400 : 611-612. Kromp, B. (1989). Carabid beetle communities (Carabidae, Coloptera) in biologically and conventionally farmed agroecosystems. Agriculture, Ecosystems and Environment 27 : 241-251. Kromp, B. (1990). Carabid beetles (Coleoptera, Carabidae) as bioindicators in biological and conventional farming in Austrian potato fields. Biology and Fertility of Soils 9: 182-187. Kromp, B. (1999). Carabid beetles in sustainable agriculture: a review on pest control efficacy, cultivation impacts and enhancement. Agriculture, Ecosystems and Environment 74 : 187-228. Kromp, B. and K.-H. Steinberger (1992). Grassy field margins and arthropod diversity: a case study on ground beetles and spiders in eastern Austria (Coleoptera: Carabidae; Arachnida: Aranei, Opiliones). Agriculture, Ecosystems and Environment 40 : 71-93. Kubišta, Z. (1990). Changes in availability of animal food for chicks of ring-necked pheasant ( Phasianus colchicus ) in farmland of southern Moravia. Folia Zoological 39 : 249-258. Kuijper, D. P. J., E. Oosterveld and E. Wymenga (2009). Decline and potential recovery of the European grey partridge ( Perdix perdix ) population—a review. European Journal of Wildlife Research 55 : 455-463.

164 Lack, D. (1983). Darwin's Finches . Cambridge, Cambridge University Press. Lazarus, J. and M. Symonds (1992). Contrasting effects of protective and obstructive cover on avian vigilance. Animal Behaviour 43 : 519-521. Leather, S. R. (2005). Insect sampling in forest ecosystems . Oxford, Blackwell Publishing. Lewis, T. (1969). The diversity of the insect fauna in a hedgerow and neighbouring fields. Journal of Applied Ecology 6: 453-458. Liukkonen-Anttila, T., A. Putaala and R. Hissa (2002). Feeding of hand-reared grey partridge ( Perdix perdix ) chicks - importance of invertebrates. Wildlife Biology 8: 11-19. Long, S., C.-q. Zhou, W.-k. Wang, W. Wei and J.-c. Hu (2007). The Habitat and Nest-site Selection of Common Pheasants in Spring and Summer in Nanchong, China. Zoological Research 28 : 249-254. Longland, W. S. and M. V. Price (1991). Direct observations of owls and heteromyid rodents: can predation risk explain microhabitat use? Ecology 72 : 2261-2273. Lovette, I. J. (2008). Convergent evolution: raising a family from the dead. Current Biology 18 : R1132-R1134. MacDonald, D. W., F. H. Tattersall, K. M. Service, L. G. Firbank and R. E. Feber (2007). Mammals, agri-environment schemes and set-aside – what are the putative benefits? Mammal Review 37 : 259-277. Maidens, D. A. and J. P. Carroll (2002). Charateristics of four agricultural crops established as northern bobwhite brood habitat . Quail V: Proceedings of the Fifth National Quail Symposium, Texas Parks and Wildlife Department, Austin, TX, USA. Marshall, E. J. P., V. K. Brown, N. D. Boatman, P. J. W. Lutman, G. R. Squire and L. K. Ward (2003). The role of weeds in supporting biological diversity within crop fields. Weed Research 43 : 77-89. Marshall, E. J. P., T. M. West and D. Klein (2006). Impacts of an agri-envionment field margin prescription on the flora and fauna of arable farmland in different landscapes. Agriculture, Ecosystems and Environment 113 : 36-44. Mastrota, F. N. and J. A. Mench (1995). Colour avoidance in northern bobwhites: effect of age, sex and previous experience. Animal Behaviour 50 : 519-526. Matson, P. A., W. J. Parton, A. G. Power and M. J. Swift (1997). Agricultural intensification and ecosystem properties. Science 277 : 504-509.

165 McNamara, J. M. and A. I. Houston (1992). Risk-sensitive foraging: a review of the theory. Bulletin of Mathematical Biology 54 : 355-378. Meek, B., D. Loxton, T. Sparks, R. Pywell, H. Pickett and M. Nowakowski (2002). The effect of arable field margin composition on invertebrate biodiversity. Biological Conservation 106 : 259-271. Mellott, R. S. and P. E. Woods (1993). An improved ligature technique for dietary sampling in nestling birds. Journal of Field Ornithology 64 : 205-210. Metcalfe, N. B. (1984). The effects of habitat on the vigilance of shorebirds: is visibility important? Animal Behaviour 32 : 981-985. Micol, T., C. P. Doncaster and L. A. Mackinlay (1994). Correlates of Local Variation in the Abundance of Hedgehogs Erinaceus europaeus . Journal of Animal Ecology 63 : 851-860. Molterer, W. (1999). Organic farming in Austria . Federal Ministry of Agriculture and Forestry, Vienna. Moody, D. T. (1970). A method for obtaining food samples from insectivorous birds. Auk 87 : 579. Moreby, S. J. (1988). A key to the identification of arthropod fragments in the faeces of gamebird chicks. Ibis 30 : 519-526. Moreby, S. J., N. J. Aebischer and S. Southway (2006). Food preference of grey partridge chicks, Perdix perdix , in relation to size, colour and movement of insect prey. Animal Behaviour 71 : 871-878. Moreby, S. J. and S. E. Southway (1999). Influence of autumn applied herbicides on summer and autumn food available to birds in winter wheat fields in southern England. Agriculture, Ecosystems and the Environment 72 : 285-197. Moreby, S. J. and C. Stoate (2000). A quantitative comparison of neck-collar and faecal analysis to determine passerine nesting diet. Bird Study 47 : 320-331. Moreby, S. J. and C. Stoate (2001). Relative abundance of invertebrate taxa in the nestling diet of three farmland passerine species, Dunnock Prunella modularis , Whitethroat Sylvia communis and yellowhammer Emberzia citinella in Leicestershire, England. Agriculture, Ecosystems and Environment 86 : 125- 134. Morris, A. J., J. M. Holland, B. Smith and N. E. Jones (2004). Sustainable Arable Farming For an Improved Environment (SAFFIE): managing winter wheat sward structure for Skylarks Alauda arvensis . Ibis 146 : 155-162.

166 Nelson, D. R., R. O. Kimmel and M. J. Frydendall (1990). Ring-necked pheasant and grey partridge brood habitat in roadsides and managed grasslands . Perdix V: Grey Partridge Workshop, Kansas Department of Wildlife and Parks, Emporia. Newton, I. (2004). The recent declines of farmland bird populations in Britain: an appraisal of causal factors and conservation actions. Ibis 146 : 579-600. Noor, M. A. F., R. S. Parnell and B. S. Grant (2008) "A Reversible Color Polyphenism in American Peppered Moth ( Biston betularia cognataria ) Caterpillars." PLoS ONE 3 DOI: e3142. doi:10.1371/journal.pone.0003142. O'Connor, R. J. and M. Shrubb (1986). Farming and birds . Cambridge, University Press. Odderskær, P., A. Prang, J. G. Poulsen, P. N. Andersen and N. Elmegaard (1997). Skylark ( Alauda arvensis ) utilisation of micro-habitats in spring barley fields. Agriculture, Ecosystems and Environment 62 : 21-29. Offerdahl, S. D. and A. J. Fivizzani (1987). The development of thermoregulation in gray partridge chicks . Perdix IV: Grey Partridge Workshop Minnesota Department of Natural Resources, Madelia. Ohlsson, T. and H. G. Smith (2001). Early nutrition causes persistent effects on pheasant morphology. Physiological and Biochemical Zoology 74 : 212-218. Olsson, O., J. S. Brown and H. G. Smith (2002). Long- and short-term state- dependent foraging under predation risk: an indication of habitat quality. Animal Behaviour 63 : 981-989. Orians, G. H. (1966). Food of nestling yellow-headed blackbirds, Cariboo Parklands, British Columbia. Condor 68 : 321-337. PACEC (2006). The Economic and Environmental Impact of Sporting Shooting . Public and Corporate Economic Consultants (PACEC), Cambridge. Palmer, W. E., M. W. Lane and P. T. Bromley (2001). Human-imprinted Northern Bobwhite chicks and indexing arthropod foods in habitat patches. Journal of Wildlife Management 65 : 861-870. Panek, M. (1997). The effect of agricultural landscape structures on food resources and survival of grey partridge Perdix perdix chicks in Poland. Journal of Applied Ecology 34 : 787-792. Panek, M. (2002). The institutional framework for nature conservation on farmland. Die Bodenkultur 53 : 217-226.

167 Parish, T., K. H. Lakhani and T. H. Sparks (1994). Modelling the relationship between bird population variables and hedgerow and other field margin attributes. I. Species richness of winter, summer and breeding birds. Journal of Applied Ecology 31 : 764-775. Peach, W. J., R. A. Robinson and K. A. Murray (2004). Demographic and environmental causes of the decline of rural Song Thrushes Turdus philomelos in lowland Britain. Ibis 146 : 50-59. Peach, W. J., P. S. Thompson and J. C. Coulson (1994). Annual and long-term variation in the survival rates of British lapwings Vanellus vanellus . Journal of Animal Ecology 63 : 60-70. Perkins, A. J., H. E. Maggs and J. D. Wilson (2008). Winter bird use of seed-rich habitats in agri-environment schemes. Agriculture, Ecosystems and Environment 126 : 189-194. Pettigrew, J. D. (1991). Wings or brain? Convergent evolution in the origins of bats. Systematic Zoology 40 : 557-563. Pfiffner, L. and H. Luke (2003). Effects of low-input farming systems on carabids and epigeal spiders – a paired farm approach. Basic and Applied Ecology 4: 117- 127. Pis, T. (2002). The body temperature and energy metabolism in growing chicks of capercaillie ( Tetrao urogallus ). Journal of Thermal Biology 27 : 191-198. Potts, G. R. (1986). The Partridge: Pesticides, Predation and Conservation . London, Collins Professional and Technical Books. Potts, G. R. and N. J. Aebischer (1991). Modelling the population dynamics of the Grey Partridge: conservation and management. Bird Population Studies: Relevance to Conservation and Management . C. M. Perrins, J.-D. Lebreton and G. J. M. Hirons. Oxford, Oxford University Press : 373-390. Poulsen, J. G., N. W. Sotherton and N. J. Aebischer (1998). Comparative nesting and feeding ecology of skylarks Alauda arvensis on arable farmland in southern England with special reference to set-aside. Journal of Applied Ecology 35 : 131-147. Purtauf, T., I. Roschewitz, J. Dauber, C. Thies, T. Tscharntke and V. Wolters (2005). Landscape context of organic and conventional farms: Influences on carabid beetle diversity. Agriculture, Ecosystems and Environment 108 : 165-174.

168 Pyke, K. L. (1989). Assessment of a technique to measure pheasant chick feeding rate with special reference to set-aside land. Centre for Environmental Technology . London, Imperial College of Science and Technology (University of London). MSc thesis . Quendler, E. (2005). Farm size structure of Austrian agriculture: how is the Austrian agriculture described by farm sizes & farm types? Die Bodenkultur 56 : 143- 150. Ralph, C. P., S. E. Nagata and C. J. Ralph (1985). Analysis of droppings to describe diets of small birds. Journal of Field Ornithology 56 : 165-174. Ramsay, S. L. and D. C. Houston (2003). Amino acid composition of some woodland arthropods and its implications for breeding tits and other passerines. Ibis 145 : 227-232. Randel, C. J., R. B. Aguirre, M. J. Peterson and N. J. Silvy (2006). Comparison of two techniques for assessing invertebrate availability for wild turkeys in Texas. Wildlife Society Bulletin 34 : 853-855. Rands, M. R. W. (1985). Pesticide use on cereals and the survival of grey partridge chicks: a field experiment. Journal of Applied Ecology 22 : 49-54. Ratcliffe, D. A. (1970). Changes attributable to pesticides in egg breakage frequency and eggshell thickness in some British birds. Journal of Applied Ecology 7: 67-115. Real, L. and T. Caraco (1986). Risk and foraging in stochastic environments. Annual Review of Ecology and Systematics 17 : 371-390. Reddersen, J. (1997). The arthropod fauna of organic versus conventional cereal fields in Denmark. Entomological Research in Organic Agriculture, Biological Agriculture and Horticulture . B. Kromp and P. Meindl, AB Academic Publishers. 15: 61-71. Regenscheid, D. H., R. O. Kimmel, R. Erpelding and A. H. Grewe (1987). Gray partridge and ring-necked pheasant brood feeding on areas managed as nesting cover . Perdix IV: Grey Partridge Workshop, Minnesota Department of Natural Resources, Madelia. Robel, R. J., J. N. Briggs, A. D. Dayton and L. C. Hulbert (1970). Relationships between visual obstruction measurements and weight of grassland vegetation. Journal of Range Management 23 : 295-297.

169 Robertson, P. (1997). A Natural History of the Pheasant . Shrewsbury, Swan Hill Press. Robertson, P. A. (1991). Estimating the nesting sucess and productivity of British pheasants Phasianus colchicus from nest-record schemes. Bird Study 38 : 73- 79. Robertson, P. A., D. R. Wise and K. A. Blake (1993). Flying ability of different pheasant strains. Journal of Wildlife Management 57 : 778-782. Robertson, R. J. (1973). Optimal niche space of the red-winged blackbird. III. Growth rate and food of nestlings in marsh and upland habitat. Wilson Bulletin 85 : 209-222. Robinson, R. A. (2005, (v1.24, June 2009)). BirdFacts: profiles of birds occurring in Britain & Ireland . BTO Research Report 407, Thetford. Retrieved 08/12/2009, from http://www.bto.org/birdfacts . Roper, T. J. (1990). Responses of domestic chicks to artifically coloured insect prey: effects of previous experience and background colour. Animal Behaviour 39 : 466-473. Rosenberg, K. V. and R. J. Cooper (1990). Approaches to avian diet analysis. Studies in Avian Biology 13 : 80-90. Sage, R. B., D. M. B. Parish, M. I. A. Woodburn and T. P. G. L (2005). Songbirds using crops planted on farmland as cover for game birds. European Journal of Wildlife Research 51 : 248-253. Sage, R. B., A. Putaala, V. Pradell-Ruiz, T. L. Greenall, M. I. A. Woodburn and R. A. H. Draycott (2003). Incubation success of released hand-reared pheasants Phasianus colchicus compared with wild ones. Wildlife Biology 9: 179-184. Savory, C. J. (1989). The importance of invertebrate food to chicks of gallinaceous species. Proceedings of the Nutrition Society 48 : 113-133. Schmitzberger, I., T. Wrbka, B. Steurer, G. Aschenbrenner, J. Peterseil and H. Zechmeister (2005). How farming styles influence biodiversity maintenance in Austrian agricultural landscapes. Agriculture, Ecosystems and Environment 108 : 274-290. Schneider, M. (2003). Austrian agriculture: experience with CAP and the anticipted effects of the EU's Eastern Enlargement. Agricultural Economics - Czech 49 : 80-86. Schoonhoven, L. M. (2005). Insect-plant biology . Oxford, Oxford University Press.

170 Schowalter, T. D. (2006). Insect ecology: an ecosystem approach . Burlington, Elevier Academic Press. Shaw, P. J. A. (2003). Multivariate statistics for the environmental sciences . London, Hodder Arnold. Sheldon, R., M. Bolton, S. Gillings and A. Wilson (2004). Conservation management of Lapwing Vanellus vanellus on lowland arable farmland in the UK. Ibis 146 : 41-49. Shiel, C., C. McAney, C. Sullivan and J. Fairley (1997). Identification of arthropod fragments in bat droppings . London, The Mammal Society. Siriwardena, G. M., S. R. Baillie, S. T. Buckland, R. M. Fewster, J. H. Marchant and J. D. Wilson (1998). Trends in the abundance of farmland birds: a quantitative comparison of smoothed Common Birds Census indices. Journal of Applied Ecology 35 : 24-43. Siriwardena, G. M., N. A. Calbrade and J. A. Vickery (2008). Farland birds and late winter food: does seed supply fail to meet demand? Ibis 150 : 585-595. Smith, B., J. Holland, N. Jones, S. J. Moreby, A. J. Morris and S. E. Southway (2009). Enhancing invertebrate food resources for skylarks in cereal ecosystems: how useful are in-crop agri-environment scheme management options? Journal of Applied Ecology 46 : 692-702. Smith, J., S. Potts and P. Eggleton (2008a). The value of sown grass margins for enchancing soil macrofaunal biodiversity in arable systems. Agriculture, Ecosystems and Environment 127 : 119-125. Smith, J., S. G. Potts, B. Woodcock and P. Eggleton (2008b). Can arable field margins be managed to enhance their biodiversity, conservation and functional value for soil macrofauna? Journal of Applied Ecology 45 : 269-278. Smith, M. D. and L. W. J. Burger (2005). Use of imprinted northern bobwhite chicks to assess habitat-specific arthropod avaiilability. Wildlife Society Bulletin 33 : 596-605. Somers, J., E. T. Moran Jr, B. S. Reinhart and G. Stephenson (1972). Effect of external application of pesticides to the egg of the hen and pheasant on hatchability and chick viability. Poultry Science 51 : 1862-1972. Sotherton, N. W. (1998). Land use changes and the decline of farmland wildlife: an appraisal of the set-aside approach. Biological Conservation 83 : 259-268.

171 Sotherton, N. W. and P. A. Robertson (1990). Indirect impacts of pesticides on the production of wild gamebirds in Britain . Perdix V: Grey Partridge Workshop, Kansas Department of Wildlife and Parks, Emporia. Southwood, T. R. E. and D. J. Cross (1969). The ecology of the partridge: III. Breeding success and the abundance of insects in natural habitats. Journal of Animal Ecology 38 : 497-509. Southwood, T. R. E. and D. J. Cross (2002). Food requirements of grey partridge Perdix perdix chicks. Wildlife Biology 8: 175-183. Standen, V. (2000). The adequacy of collecting techniques for estimating species richness of grassland invertebrates. Journal of Applied Ecology 37 : 884-893. Starck, J. M. and R. E. Ricklefs (1998). Avian growth and development: evolution within the altricial-precocial system . New York, Oxford University Press. Steffan-Dewenter, I. and T. Tscharntke (1997). Early succession of butterfly and plant communities on set-aside fields. Oecologia 109 : 294-302. Steffan-Dewenter, I. and T. Tscharntke (2001). Succession of bee communities on fallow. Ecography 24 : 83-93. Stoate, C., N. D. Boatman, R. J. Borralho, C. Rio Carvalho, G. R. de Snoo and P. Eden (2001). Ecological impacts of arable intensification in Europe. Journal of Environmental Management 63 : 337-365. Stoate, C., S. J. Moreby and J. Szczur (1998). Breeding ecology of farmland yellowhammers Emberiza citrinella . Bird Study 45 : 109-121. Stoate, C. and J. Szczur (2001). Whitethroat Sylvia communis and Yellowhammer Emberiza citrinella nesting success and breeding distribution in relation to field boundary vegetation. Bird Study 48 : 229-235. Stowe, T. J., A. V. Newton, R. E. Green and E. Mayes (1993). The decline of the corncrake Crex crex in Britain and Ireland in relation to habitat. Journal of Applied Ecology 30 : 53-62. Suhonen, J. (1993). Predation rish influences the use of foraging sites by tits. Ecology 74 : 1197-1203. Surmacki, A. (2005). Do dense and fast growing crops provide foraging habitats for insectivorous birds? Polish Journal of Ecology 53 : 129-133. Taylor, R. L., B. D. Maxwell and R. J. Boik (2006). Indirect effects of herbicides on bird food resources and beneficial arthropods. Agriculture, Ecosystems and Environment 116 : 157-164.

172 Ter Braak, C. J. (1986). Canonical correspondence analysis: a new eigenvector techniqie for multivariate direct gradient analysis. Ecology 67 : 1167-1179. Tew, T. E., D. W. MacDonald and M. R. W. Rands (1992a). Herbicide Application Affects Microhabitat Use by Arable Wood Mice ( Apodemus sylvaticus ) Journal of Applied Ecology 29 : 532-539. Tew, T. E., D. W. MacDonald and M. R. W. Rands (1992b). Herbicide application affects microhabitat use by arable wood mice ( Apodemus sylvaticus ). Journal of Applied Ecology 29 : 532-539. Thomas, C. F. G., L. Parkinson, G. J. K. Griffiths, A. F. Garcia and E. J. P. Marshall (2001). Aggregation and temporal stability of carabid beetle distributions in field and hedgerow habitats. Journal of Applied Ecology 38 : 100-116. Toepfer, S. and M. Stubbe (2001). Territory density of the Skylark ( Alauda arvensis ) in relation to field vegetation in central Germany. Journal für Ornithologie 142 : 184-194. Toft, S. (2005). The quality of aphids as food for generalist predators: implications for natural control of aphids. European Journal of Entomology 102 : 371-383. Törmälä, T. (1982). Evaluation of five methods of sampling field layer arthropods, particularly the leafhopper community, in grassland. Annales Entomologici 48 : 1-16. Treweek, J., M. Drake, O. Mountfield, C. Newbold, C. Hawke, P. Jose, M. Self and P. Benstead (1997). The wet grassland guide : managing floodplain and coastal wet grasslands for wildlife Sandy, RSPB. Tscharntke, T., A. M. Klein, A. Kruess, I. Steffan-Dewenter and C. Thies (2005). Landscape perspectives on agricultural intensification and biodiversity - ecosystem service management. Ecology Letters 8: 857-874. Tucker, G. M. and M. F. Heath (1994). Birds in Europe: their conservation status . Cambridge, BirdLife International. Van Buskirk, J. and Y. Willi (2004). Enhancement of farmland biodiversity within set-aside land. Conservation Biology 18 : 987-994. Verboom, B. and H. Huitema (1997). The importance of linear landscape elements for the pipistrelle Pipistrellus pipistrellus and the serotine bat Eptesicus serotinus . Landscape Ecology 12 : 117-125. Vickerman, G. P. and M. O'Bryan (1979). Partridges and insects. Annual Review of the Game Conservancy . 9: 35-43.

173 Vickery, J., N. Carter and R. J. Fuller (2002). The potential value of managed cereal field margins as foraging habitat for farmland birds in the UK. Agriculture, Ecosystems and Environment 89 : 41-52. Vickery, J. A., R. B. Bradbury, I. G. Henderson, M. A. Eaton and P. V. Grice (2004). The role of agri-environment schemes and farm management practices in reversing the decline of farmland birds in England. Biological Conservation 119 : 19-39. Vickery, J. A., R. E. Feber and R. J. Fuller (2009). Arable field margins managed for biodiversity conservation: A review of food resource provision for farmland birds. Agriculture, Ecosystems and the Environment 133 : 1-13. Wakham-Dawson, A., K. Szoszkiewicz, K. Stern and N. J. Aebischer (1998). Breeding skylarks Alauda arvensis on Environmentally Sensitive Area arable reversion grass in southern England: survey-based and experimental determination of density. Journal of Applied Ecology 35 : 635-648. Walsh, A. L. and S. Harris (1996). Foraging Habitat Preferences of Vespertilionid Bats in Britain Journal of Applied Ecology 33 : 508-518. Wang, N., Z. Zhang, Z. G. and P. J. K. McGowen (2004). Relative density and habitat use of four pheasant species in Xiaoshennongjia Mountains , Hubei Province, China. Bird Conservation International 14 : 43-54. Warner, R. E., S. L. Etter, G. B. Joselyn and J. A. Ellis (1984). Declining survival of ring-necked pheasant chicks in Illinois agricultural ecosystems. Journal of Wildlife Management 48 : 82-88. Werdelin, L. (1986). Comparison of skull shape in marsupial and placental carnivores. Australian Journal of Zoology 34 : 109-117. Whittingham, M. J., S. J. Butler, J. L. Quinn and W. Cresswell (2004). The effect of limited visibility on vigilance behaviour and speed of predator detection: implications for the conservation of granivorous passerines. Oikos 106 : 377- 385. Whittingham, M. J. and K. L. Evans (2004). The effects of habitat structure on predation risk of birds in agricultural landscapes. Ibis 146 : 210-220. Whittingham, M. J., R. D. Swetnam, J. D. Wilson, D. E. Chamberlain and R. P. Freckleton (2005). Habitat selection by yellowhammers Emberiza citrinella on lowland farmland at two spatial scales: implications for conservation management. Journal of Applied Ecology 42 : 270-280.

174 Wilson, A., J. Vickery and C. Pendlebury (2007). Agri-environment schemes as a tool for reversing declining populations of grassland waders: Mixed benefits from Environmentally Sensitive Areas in England. Biological Conservation 136 : 128-135. Wilson, A. M., M. Ausden and T. P. Milsom (2004). Changes in breeding wader populations on lowland wet grasslands in England and Wales: causes and potential solutions. Ibis 146 : 32-40. Wilson, A. M., J. A. Vickery and S. J. Browne (2001). Numbers and distribution of Northern Lapwings Vanellus vanellus breeding in England and Wales in 1998. Bird Study 48 : 2-17. Wilson, J. D., J. Evans, S. J. Browne and J. R. King (1997). Territory distribution and breeding success of skylarks Alauda arvensis on organic and intensive farmland in southern England. Journal of Applied Ecology 34 : 1426-1478. Wilson, J. D., A. J. Morris, B. E. Arroyo, S. C. Clark and R. B. Bradbury (1999). A review of the abundance and diversity of invertebrate and plant foods of granivorous birds in northern Europe in relation to agricultural change. Agriculture, Ecosystems and Environment 75 : 13-30. Wilson, J. D., M. J. Whittingham and R. B. Bradbury (2005). The management of crop structure: a general approach to reversing the impacts of agricultural intensification on birds? Ibis 147 : 453-463. Wilson, M. F. (1966). Breeding ecology of the yellow-headed blackbird. Ecological Monographs 36 : 51-77. Winspear, R. and G. Davies (2005). A management guide to birds of lowland farmland . Sandy, The RSPB. Wolda, H. (1990). Food availability for an insectivore and how to measure it. Studies in Avian Biology 13 : 38-43. Woodcock, B. A., D. B. Westbury, T. Tscheulin, J. Harrison-Cripps, S. J. Harris, A. J. Ramsey, V. K. Brown and S. G. Potts (2008). Effects of seed mixture and management on beetle assemblages of arable field margins. Agriculture, Ecosystems and Environment 125 : 246-254. Wrbka, T., S. Schindler, M. Pollheimer, I. Schmitzberger and J. Peterseil (2008). Impact of the Austrian Agri-Environmental Scheme on diversity of landscapes, plants and birds. Community Ecology 9: 217-227.

175 Wretenberg, J., Å. Lindström, S. Svensson, T. Thierfelder and T. Pärt (2006). Population trends of farmland birds in sweden and England: similar trends but different patterns of agricultural intensification. Journal of Applied Ecology 43 : 1110-1120. Yapp, W. B. (1983). Game-birds in medieval England. Ibis 125 : 218-221.

176 Appendix I. Flora of the Seefeld estate

Flora surveys conducted by Johannes Huspek between 1997 and 2001.

Scientific name Common name Scientific name Common name Acer campestre Field maple Lathyrus tuberosus Earthnut pea Acer negundo Box maple Lepidium ruderale Narrow-leaved Acer platanoides Norway maple pepperwort Achillea milefolium agg. Yarrow Ligustrum vulgare Wild privit Achillea pannonica Pannonian yarrow Linaria vulgaris Common toadflax Aegopodium podagraria Ground elder Lolium perenne Perenial ryegrass Argostis sp. Bentgrass Lotus corniculatus Birdsfoot trefoil Allium senescens ssp. Mountain garlic Lotus maritimus Asparagus pea montanum Lycium barbarum Box thorn Alnus glutinosa Black alder Lysimachia vulgaris Yellow loosestrife Alopecurus pratensis Meadow foxtail Lythrum salicaria Purple loosestrife Althaea officinalis Marshmallow Malus domestica Apple Amaranthus retroflexus Redroot pigweed Malva neglecta Common mallow Amaranthus sp. Aramanth Medicago varia Alfalfa Anagallis arvensis Scarlet pimpernel Medicago lupulina Black medic Anchusa officinalis Alkanet Melica transsilvanica Red Spire Anthriscus sylvestris Cow parsley Mentha longifolia Horse mint Apera spica-venti Loose silky-bent Mentha sp. Mint Arctium lappa Burdock Mercurialis annua Annual mercury Arctium tomentosa Woolly burdock Morus alba White mulberry Arenaria serpyllifolia agg. Thyme-leaved Myosotis arvensis Field forget-me-not sandwort Myosotis sparsiflora Asparagaceae Aristolochia clematitis Birthwort forget-me-not Arrhenatherum elatius False oat-grass Myosoton aquaticum Water chickweed Artemisia absinthium Wormwood Onobrychis vicifolia Sainfoin Artemisia vulgaris Mugort Onopordum acanthium Cotton thistle Asparagus officinalis Asparagus Origanum vulgare Oregano Asperugo procumbens Madwort Panicum miliaceum Proso millet Aster lanceolatus Panicled aster Papaver rhoeas Common poppy Aster novi-belgii Michaelmas daisy Pastinaca sativa Wild parsnip Astragalus cicer Cicer milkvetch Phalaris arundinacea Reed canary grass Astragalus glycyphyllos Wild liquorice Phleum pratense Timothy Atriplex patula Common orache Phragmites australis Common reed Atriplex sagittata Shining orache Picris hieracioides Hawkweed Avena fatua Wild oat oxtongue Ballota nigra Black horehound Plantago major ssp. Greater plantain Betula pendula Silver birch intermedia Bolboschoenus maritimus Sea club rush Plantago major Greater plantain Brachypodium sylvaticum False broom Poa annua Annual meadow Brassica napus Oilseed rape grass Bromus hordeaceus Soft brome Poa nemoralis Wood meadow Bromus inermis Smooth brome grass Bromus japonicus Japanese brome Poa pratensis Smooth meadow Bromus sterilis Barren brome grass Bromus tectorum Drooping brome Poa trivialis Rough meadow Bryonia dioica White bryony grass Calamagrostis epigejos Wood small-reed Polygonum aviculare Knotgrass Calystegia sepium Hedge bindweed Populus alba White poplar Capsella bursa-pastoris Shepards purse Populus nigra Black poplar Carduus acanthoides Spiny plumeless Potentilla reptans Creeping cinquefoil thistle Prunus spinosa Blackthorn Carduus crispus Welted thistle Pyrus pyraster Wild pear Cardaria draba Hoary cress Quercus robar Pedunculate oak Carex hirta Hairy sedge Quercus rubra Red oak Carex muricata agg. Rough sedge Ranunculus lanuginosus Woolly buttercup Carex riparia Great pond-sedge Ranunculus repens Creeping buttercup Carex sp. Sedges Raphanus raphanistrum Wild radish Carpinus betulus Common hornbeam agg. Centaurea cyanus Cornflower Reseda lutea Wild mignonette Cephalanthera White helleborine Reseda luteola Weld damasonium Rhamnus cathartica Buckthorn cf. Crepis sp. Hawksbeard Robinia pseudacacia Black locust cf. Festuca rupicula Furrowed fescue Rosa sp. Rose Chelidonium majus Greater celadine Rubus caesius Dewberry Chenopodium album White goosefoot Rubus sp. Brambles Chenopodium ficifolium Fig-leaved goosefoot Rumex acetosa Common Sorrel Chenopodium hybridum Maple-leaved Rumex cripus Curled Dock goosefoot Rumex obtusifolia Broad-leaved Dock Cichorium intybus Common chicory Salix alba White willow

177 Cirsium arvense Creeping thistle Salix rubens Hutchinson's Yellow Cirsium cf. palustre Marsh thistle Salix triandra Almond willow Cirsium vulgare Spear thistle Salvia nemorosa Sage Clinopodium vulgare Wild basil Sambucus nigra Common Elder Conium maculatum Hemlock Sclerochloa dura Hardgrass Convolvulus arvensis Field bindweed Scrophularia nodosa Common figwort Conyza canadensis Canadian Horseweed Scrophularia umbrosa Green figwort Cornus sanguinea Common dogwood Securigera varia Crown vetch Crataegus monogyna Hawthorn Secale cereale Rye Cuscuta europaea Dodder Sedum acre Biting stonecrop Cynoglossum officinale Houndstongue Seseli Libanotis Moon carrot Dactylis glomerata Cocksfoot Setaria verticillata Bristly bristle-grass Datura stramonium Thorn apple Setaria viridis Green bristle-grass Daucus carota Wild carrot Silene latifolia ssp. alba White campion Descurainia sophia Flixweed Silene noctiflora Night-flowering Dipsacus fullonum Wild teasel catchfly Echinops Globe thistle Sinapis arvensis Wild mustard sphaerocephalus Sisymbrium altissimum Tall rocket Elymus repens Couch grass Sisymbrium loeselii False London-rocket Epipactis helleborine Broad-leaved Sisymbrium orientale Indian hedge helleborine mustard Equisetum arvense Field horsetail Solidago gigantea Early goldenrod Erigeron acris Bitter fleabane Sonchus arvensis Corn sow-thistle Erodium cicutarium Common storksbill Sonchus asper Rough sow-thistle Eryngium campestre Field eryngo Sonchus olcraccus Smooth sow-thistle Euphorbia esula Leafy spurge Sonchus sp. Sow-thistle Euphorbia helioscopa Sun spurge Stachys palustris Marsh woundwort Evonymus europaea Spindle Stellaria holostea Greater stitchwort Falcaria vulgaris Sickleweed Stellaria media Common chickweed Fallopia convolvulus Black bindweed Symphytum officinale Common comfrey Festuca pratensis Meadow fescue Syringa vulgaris Lilac Festuca sp. Fescue grass Taraxacum officinale agg. Dandelion Fraxinus excelsior Ash Thalictrum lucidum Meadow rue Fraxinus pennsylvanica Green ash Thlaspi arvense Field penny-cress Galium aparine Cleavers Torilis japonica Hedge-parsley Galium mollugo agg. Hedge bedstraw Tragopogon orientalis Eastern goatsbeard Galium verum Lady's bedstraw Trifolium medium Zigzag clover Geranium molle Dovesfoot cranesbill Trifolium pratense Red clover Geranium pusillum Small-flowered Trifolium repens White clover cranesbill Tripleurospermum Scentless mayweed Geum urbanum Wood avens inodorum Glechoma hederacea Ground ivy Trisetum flavescens Yellow oat-grass Helianthus annuus Sunflower Triticum aestivum Bread wheat Helianthus tuberosus Jerusalem artichoke Tussilago farfara Coltsfoot Heracleum sphondylium Common hogweed Typha latifolia Bulrush Hieracium sabaudum European hawkweed Ulmus laevis European white elm Hordeum murinum False barley Ulmus minor Small-leaved elm Humulus lupulus Common hop Urtica dioica Common nettle Hyoscyamus nigra Hensbane Valeriana officinalis Common valerian Hypericum perforatum St. John's wort Veronica arvensis Wall speedwell Inula britannica British yellowhead Veronica hederifolia agg. Ivy-leaved Iris pseudacorus Yellow flag speedwell Lactuca serriola Prickly lettuce Veronica persica Common field Lamium album White deadnettle speedwell Lamium amplexicaule Greater henbit Vicia cracca agg. Tufted vetch Lamium maculatum Spotted white Vicia sepium Bush vetch deadnettle Viola arvensis Field pansy Lamium purpureum Red deadnettle cf. Viola collina Hill violet Lapsana communis Nipplewort Viola odorata Sweet violet Lathyrus pratensis Meadow vetchling * Rare species ** Locally rare species

178 Appendix II. Birds of Seefeld estate

Compiled from observations by Dr. Hans-Martin Berg and Karl Pock in 1998 with additions by Brandon Anderson in 1999 – 2000, also Claire Whittington and Gwen Hitchcock in 2008.

Scientific name Common name Scientific name Common name Accipiter gentiles Goshawk Hippolais icterina Icterine warbler Acrocephalus palustris Marsh warbler Hirundo rustica Barn swallow Acrocephalus scirpaceus Reed warbler Ixobrychus minutus Little bittern Alauda arvensis Skylark Jynx torquilla Wryneck Alcedo atthis Kingfisher Lanius collurio Red-backed shrike Anas crecca Teal Lanius excubitor Great grey shrike Anas ferina Pochard Larus ridibundus Black-headed gull Anas fuligula Tufted duck Locustella fluviatilis River warbler Anas platyrhynchos Mallard Locustella naevia Grasshopper warbler Anas querquedula Garganey Luscinia Nightingale Anthus trivialis Tree pipit megarhynchos Apus apus Swift Miliarea calandra Corn bunting Ardea cinerea Grey heron Motacilla alba White wagtail Asio otus Long-eared owl Motacilla flava Yellow wagtail Athene noctua Little owl Musicapa striata Spotted flycatcher Botaurus stellaris Bittern Nycticorax nycticorax Black-crowned night Bubo bubo Eagle owl Heron Buteo buteo Buzzard Oriolus oriolus Golden oriole Carduelis cannabina Linnet Parus caeruleus Blue tit Carduelis chloris European greenfinch Parus major Great tit Cardvelis carduelis Goldfinch Passer domesticus Housesparrow Charadrius dubious Little ringed plover Passer montanus Tree sparrow Ciconia ciconia White stork Perdix perdix Grey partridge Ciconia nigra Black stork Pernis apivorus Honey buzzard Circus aeruginosus Marsh harrier Philloscopus collipitus Chiffchaff Circus pygargus Montagues’ harrier Phoenicurus ochruros Black redstart Coccothraustes Hawfinch Phylloscopus trochilus Willow warbler coccothraustes Pica pica Magpie Columba palumbus Wood pigeon Picoides medius Middle spotted Corvus corone cornix Hooded crow woodpecker Corvus corone corone Carrion crow Picus viridis Green woodpecker Coturnix cortunix Quail Remis pendulinus Penduline tit Coulmba oenas Stock dove Saxicola rubetra Whinchat Cuculus canorus Cuckoo Saxicola torquata Stonechat Delichon urbica House martin Serinus serinus Serin Dendrocopos major Great spotted Starnus vulgaris Starling woodpecker Streptopelia decaocto Collared dove Dentrocopos syriacus Syrian woodpecker Streptopelia turtur Turtle dove Egretta garzetta Little egret Sylvia atricapilla Blackcap Emberiza schoenicus Reed bunting Sylvia borin Garden warbler Emeriza citrinella Yellowhammer Sylvia communis Whitethroat Erithacus rubecula European robin Sylvia curruca Lesser whitethroat Falco subbuteo Northern hobby Sylvia nisoria Barred warbler Falco tinnunculus Kestrel Tringa ochropus Green sandpiper Fringilla coelebs Chaffinch Turdus merula Blackbird Fulica atra Coot Turdus philomelos Song thrush Galinula chloropus Moorhen Turdus viscivorus Mistle thrush Garrulus glandarius European jay Upupa epops Hoopoe Haliaeetus albicilla White-tailed eagle Vanellus vanellus Lapwing

179