Bird Trends in the Heart of England 1977-2016

Bird Trends in the Heart of England, 1977-2016

A review of the population trends of Farmland and Woodland species in south central England compared to the whole of England

Mike Curnow Bird Recorder Banbury Ornithological Society www.banburyos.org December 2018

Bird Trends in the Heart of England, 1977-2016 Contents 1. Summary ...... 5 2. Introduction ...... 6 3. Overview of the Information Sources ...... 6 4. Bird Indices ...... 7 5. Farmland Bird Trends ...... 8 5.1 Farmland Bird Index ...... 8 5.2 Farmland Species Comparison ...... 12 5.3 Farmland Trends Summary ...... 13 5.4 Conclusion ...... 13 6. Woodland Bird Trends ...... 14 6.1 Woodland Bird Index ...... 14 6.2 Woodland Species Comparison ...... 18 6.3 Woodland Trends Summary ...... 19 6.4 Woodland Trends Conclusion ...... 19 7. Species Status...... 20 7.1 Format of Each Species Report ...... 20 7.2 GREY PARTRIDGE Perdix perdix ...... 21 7.3 SPARROWHAWK Accipiter nisus ...... 22 7.4 KESTREL Falco tinnunculus ...... 24 7.5 LAPWING Vanellus vanellus ...... 25 7.6 STOCK DOVE Columba oenas ...... 27 7.7 WOODPIGEON Columba palumbus ...... 28 7.8 GREEN WOODPECKER Picus viridis ...... 29 7.9 GREAT SPOTTED WOODPECKER Dendrocopos major ...... 30 7.10 JAY Garrulus glandarius ...... 32 7.11 JACKDAW Corvus monedula ...... 33 7.12 ROOK Corvus frugilegus ...... 34 7.13 GOLDCREST Regulus regulus ...... 35 7.14 BLUE TIT Cyanistes caeruleus ...... 36 7.15 GREAT TIT Parus major ...... 37 7.16 COAL TIT Periparus ater ...... 37 7.17 WILLOW TIT Poecile montana ...... 39 7.18 MARSH TIT Poecile palustris...... 40 7.19 SKYLARK Alauda arvensis ...... 41 7.20 LONG-TAILED TIT Aegithalos caudatus ...... 42 7.21 CHIFFCHAFF Phylloscopus collybita...... 44 7.22 WILLOW WARBLER Phylloscopus trochilus ...... 45 2

Bird Trends in the Heart of England, 1977-2016 7.23 BLACKCAP Sylvia atricapilla ...... 46 7.24 GARDEN WARBLER Sylvia borin ...... 47 7.25 LESSER WHITETHROAT Sylvia curruca ...... 48 7.26 WHITETHROAT Sylvia communis ...... 49 7.27 NUTHATCH Sitta europaea ...... 50 7.28 TREECREEPER Certhia familiaris ...... 51 7.29 WREN Troglodytes troglodytes ...... 52 7.30 STARLING Sturnus vulgaris ...... 52 7.31 BLACKBIRD Turdus merula ...... 53 7.32 SONG THRUSH Turdus philomelos ...... 54 7.33 SPOTTED FLYCATCHER Muscicapa striata ...... 55 7.34 ROBIN Erithacus rubecula ...... 57 7.35 DUNNOCK Prunella modularis ...... 57 7.36 TREE SPARROW Passer montanus ...... 58 7.37 CHAFFINCH Fringilla coelebs ...... 61 7.38 GREENFINCH Chloris chloris ...... 61 7.39 GOLDFINCH Carduelis carduelis ...... 63 7.40 LINNET Linaria cannabina ...... 64 7.41 BULLFINCH Pyrrhula pyrrhula ...... 65 7.42 YELLOWHAMMER Emberiza Citronella ...... 66 7.43 REED BUNTING Emberiza schoeniclus ...... 67 7.44 CORN BUNTING Emberiza calandra ...... 69 7.45 Species Summary ...... 72 8. Conclusion ...... 74 9. Appendices ...... 75 9.1 National Bird Trends Data ...... 75 9.2 BTO Bird Trend Data ...... 76 9.3 BOS Bird Trends Data ...... 76 9.4 Trends Analysis Statistical Techniques ...... 77 9.5 BOS Survey Area Map ...... 78 9.6 BOS Area Land Cover Map ...... 79 9.7 Acknowledgements ...... 79 9.8 Glossary of Terms ...... 80 10. References ...... 80

Bird Trends in the Heart of England, 1977-2016 Copyright and Contact

This report was compiled by Mike Curnow, Bird Recorder for the Banbury Ornithological Society (BOS) from the analysis of records of BOS members. Frances Buckel, Mike Pollard, Helen Raine and Jonathan Bowley provided additional input and editorial corrections. The report may be reproduced in full or in part with the appropriate citation. The statistical data within this report belong to the BOS and the BTO and must not be reproduced without prior permission of the respective owners.

The author would like to thank those who provided information and advice which informed this work, and especially to Trevor Easterbrook who instigated the surveys on which this work is based.

The author is responsible for the methods employed and any errors in the analysis.

Contact: Mike Curnow ([email protected])

Bird Trends in the Heart of England, 1977-2016 1. Summary This report provides a detailed analysis of the population trends of farmland and woodland bird species within the Banbury Ornithological Society (BOS) study area. A key feature of the report is the comparison of the status of the birds within the BOS study area against the latest national (English) trends published by Defra. This is achieved by comparing the abundance trends of farmland and woodland bird species locally and nationally. The second part of the report presents detailed statistics and graphs on the species within the farmland and woodland categories. The study shows that there is a close correlation between the Defra English farmland bird species index and BOS summer and winter surveys. The situation is significantly different for species in the English woodland index. The national trend is a small decline over the entire period, whereas the BOS study area showed a significant decline from 1994-2000, followed by a period of recovery to 2010 and then another ongoing decline.

In England, 37% of farmland birds (in the survey Status of BOS Farmland and Woodland Birds index) experienced a decline from 1993-2015 1993-2015 (Defra, 2017) compared to 47% within the BOS study area. The species of concern locally are: Tree Sparrow, Lapwing, Greenfinch, Corn Bunting, Strong Decline Grey Partridge, Linnet, Skylark, Starling and 12% 22% Weak Decline Yellowhammer. 10% In England, 26% of the woodland birds (in the No Change survey index) have experienced a decline from Weak Increase 1993-2015 (Defra, 2017) compared to 38% within 20% the BOS study area. The species of concern locally 37% Strong Increase are: Willow Warbler, Sparrowhawk, Spotted Flycatcher, Garden Warbler, Treecreeper, Marsh Tit and Willow Tit. Of immediate conservation concern are major declines in five species that were formerly widespread but which are now extremely localised and vulnerable to extinction in the study area: Grey Partridge, Lapwing, Willow Tit, Tree Sparrow and Corn Bunting. This report will be shared with organisations that have an interest in, and influence upon, farmland and woodland bird conservation. We hope it can also be used to help promote awareness of the need for urgent action for declining species to prevent their extinction in our area.

Bird Trends in the Heart of England, 1977-2016 2. Introduction The BOS has previously used its long-term monitoring datasets to publish reports on the status of birds within the area, the most recent being Birds of the Heart of England (Easterbrook, 2013), but statistical comparisons with national trends has not been performed before. One of the aims of this report is to determine if the population trends of farmland and woodland species within the study area of the BOS match those of England. It also aims to determine which species are undergoing the greatest population declines. This will help to provide local wildlife and government organisations specific evidence on the impact of environmental changes within the survey area. The report deliberately only includes data on the Defra farmland and woodland indicator species (see section “National Bird Trends Data”), rather than all birds occurring within the BOS. This enables the direct comparison of the status of key species. The other species categories assessed by Defra contain many species that are uncommon or non-breeders within the BOS, so they cannot be directly assessed. Trends are analysed for the periods that are currently available in both the national and BOS datasets. The report uses data for 1977-2015 for individual species and 1977-2016 for the summarised data (see appendices for the data sources). One of the main aims of the BOS is to monitor the status of birds in the Banbury area, defined as 1200km2 covering Chipping Norton, Bicester, Kineton and Byfield, centred on Banbury. To this end, various annual surveys are performed, the key ones for this report being the Summer and Winter random square surveys. The data from these surveys enables BOS to monitor bird populations for abundance and distribution. The BOS area is largely rural with only 2 large towns (Banbury and Bicester), with the land mostly used for arable and improved pasture. It covers north Oxfordshire (50% of the BOS), south Warwickshire (25%) and south-west Northamptonshire (25%). It is a central region in southern England, on the watershed of 3 major English river systems: the Thames (R. Cherwell), the Severn (R. Avon) and the Nene. The table below, based on The Centre for Ecology and Hydrology (CEH) land cover data (CEH: Rowland et al., 2017), shows that the land usage in the BOS is primarily agricultural (89.7%), with little woodland and minimal un-improved grassland compared to England. Land Cover % England BOS Arable 36.0% 57.0% Improved Grassland 32.4% 32.7% Other Grassland 5.3% 0.1% Woodland 9.6% 4.7% Urban 10.7% 5.3%

Maps of the BOS area and dominant land cover within the BOS are provided in the appendices. 3. Overview of the Information Sources The following national reports and underlying data are referenced within this report: • Wild Bird Populations in England, 1970-2016. Published by the Joint Nature Conservation Committee (JNCC), available from https://www.gov.uk/government/statistics/wild-bird-populations-in-england • UK Biodiversity Indicators 2018, published by the JNCC (Joint Nature Conservation Committee) in conjunction with Defra. See https://jncc.defra.gov.uk/ukbi. The relevant section is “Birds of the wider countryside”. This report is a summary of the JNCC “Wild Bird Populations” report. • State of UK Birds 2017, published by RSPB in conjunction with the BTO, WWT, Defra, JNCC. Available from the BTO website at Research > Publications > State of UK Birds: https://www.bto.org/research-data- services/publications/state-uk-birds

Bird Trends in the Heart of England, 1977-2016 The datasets used in this report are: • The Defra/JNCC bird indicators, 1970-2016, produced by the BTO for Defra o The unsmoothed data for England have been used and are identified as UKBI within this report (UK Bird Indicator) • The BTO breeding bird indices, 1966-2015 o The unsmoothed data for England have been used and are identified as BBS (Breeding Bird Survey) within this report o BTO exclude the last year of survey data in their indices, hence the data ending in 2015 and not 2016 • The BOS summer breeding bird survey (SRSS) indices, 1993-2016 • The BOS winter survey (WRSS), 1977-2016 Details on the data sources and survey methods are provided in the Appendices. Because the BOS surveys cover two different periods, this report provides comparative trends for the periods 1977- 2016 (40 years) and 1993-2016 (24 years). This conveniently provides a medium and long-term assessment period. Defra combine the data on individual species into groups to create “indicators” for different environments. For this report, the farmland and woodland indicators are used since they are the most relevant to the BOS landscape. The corresponding species are also analysed to determine if there are species specific differences in the two regions. The equivalent data from the BOS have been combined into the same species groups as used by Defra to enable a comparison of the indicators and species trends between the BOS and England. 4. Bird Indices To enable the comparison of bird population changes across time, different regions and between species, the absolute population numbers detected in surveys are converted into an index value. A specific year is chosen (1993 for this report), and the population for each species in that year is assigned the value 100. For other years, the population is converted to an index value by dividing the population by the population value for the base year (i.e. 1993 in this report) and then multiplying by 100 (similar to how you calculate a percentage). This provides a relative value of the population for each species. If the index value is less than 100, then the population has declined, and if it is greater than 100 then the population has increased. This allows the detection of the rate of change in the population for each species. It also facilitates the comparison of the rates of change between species. Further, by calculating the indices in the same way, it provides a way to compare the trends in bird populations locally and nationally. Note that a species with an index value of 150 for England and 70 for the BOS does not mean that the species is less abundant within the BOS. Rather, it means that nationally the population has increased whereas locally it has declined. The index values from multiple species can be combined to create an indicator value which shows the rate of population change for a group of similar species, such as farmland. This is the value that the Defra farmland and woodland indicators represent. The BOS indices have been combined using the same statistical technique used by Defra/BTO, enabling a direct comparison between the two datasets. The BTO produce indices for the UK, England and the English regions. The BOS area covers three English regions (East & West Midlands and the South East), so the indices for England are used in this report for comparison with the BOS. It must be noted that whilst the indices are presented here as a single annual figure, they are in fact an estimate within a range of values. The lower and upper ranges are known statistically as the “confidence” values. The ranges have been omitted from this report to simplify the presentation and to assist with the comparison of the local and national datasets. The aim of this report is to focus on the overall trends, that is the pattern of change over a period of time, so the exact figures for each year are of lesser importance than the relative amount of change.

Bird Trends in the Heart of England, 1977-2016 5. Farmland Bird Trends 5.1 Farmland Bird Index The Farmland Bird Index for England has declined by 57% since 1970 and by 8% from 2010-2015 (Defra, 2017). The index is comprised of 19 species as listed below. A major decline happened in the 1970s and early 1980s, attributed to the impact of rapid changes in many farmland management practices during this period (Defra, 2017). 58% of the species in the index show a weak or strong decline since 1970 (Defra, 2017). The species in the farmland bird index are: • Generalist: Greenfinch, Jackdaw, Kestrel, Reed Bunting, Rook, Woodpigeon, Yellow Wagtail • Specialist: Corn Bunting, Goldfinch, Linnet, Skylark, Starling, Stock Dove, Tree Sparrow, Whitethroat, Yellowhammer, Grey Partridge, Lapwing, Turtle Dove Species names in italic are not included in the BOS SRSS equivalent farmland index due to insufficient survey data - they only breed in low numbers or no longer breed locally, so are not measured accurately enough in the BOS surveys. The Defra farmland index values presented in this report are the unsmoothed values to enable a better comparison with the BOS statistics which are not smoothed (see Appendix 9.4 for details on the statistical processes). The Defra index includes all of the species listed above – it has not been recalculated to omit them. Whilst this means the species make up between the Defra index and BOS index is slightly different, this has been chosen so that the Defra statistics in this report match those in the Defra publications. 5.1.1 Farmland Bird Index Compared to BOS Summer Random Square Survey The chart below shows the breeding abundance trend for species in the farmland bird index for the period 1993- 2016 for England (UKBI) and the BOS (SRSS). The period is constrained by the BOS SRSS period. To enable comparison between the two datasets, the UKBI data (from Defra) has been scaled so that the index begins at 100 in 1993, the year that the SRSS index starts. A value of 110 means 10% higher population, 90 means 10% lower, and so- on.

All Farmland Breeding Birds UKBI SRSS UKBI Trend SRSS Trend 140 130 120 110 100 90

80 Index (100 in 1993) in (100 Index 70 60 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016

The greater variation in the BOS data is in part due to the smaller survey sizes and the different survey methodology used compared to the Defra/BTO data. The dotted lines show the linear trend for the English and BOS farmland species, which provides a rough guide to the overall population trend. See Appendix 9.4 for further information on the statistical methods used within this report (9.4.1 for Survey data processing and 9.4.2 for trend line analysis). For the period 1993-2016 there has been a 19% national decline in population and 12% for the BOS. The trendlines indicate a faster rate of decline, 22% nationally and 27% locally. Taking account of the smaller size of the BOS dataset, which impacts the amount of annual variation (the statistical confidence intervals), the overall conclusion is that the decline in farmland birds within the BOS is similar to the overall English trend.

Bird Trends in the Heart of England, 1977-2016 Looking at Generalist farmland species, it is apparent there has been little change over the period, both nationally and locally, as shown in the following chart. This indicates that these species have managed to adapt to the changes in farming practices.

Generalist Farmland Breeding Birds UKBI SRSS 180

160

140

120

Index (100 in 1993) in (100 Index 100

80 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016

Trendlines have not been shown because there is no statistically significant trend in both cases. The SRSS peak around 2006 is due to short-term increases in populations of Greenfinch, Jackdaw and Kestrel, which have subsequently declined, Greenfinch particularly so. No research has been conducted by the BOS as to why this local peak occurred. The situation is significantly different for the Specialist farmland species. There has been a 29% decline nationally and 22% locally over the 24-year period (1993-2016). The linear trend lines indicate a faster rate of decline, 31% nationally and 48% locally, though the there is considerable variation in the BOS figures, so a linear trend is not a good fit.

Specialist Farmland Breeding Birds UKBI SRSS UKBI Trend SRSS Trend 140 130 120 110 100 90 80 Index (100 in 1993) in (100 Index 70 60 50 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016

The conclusion is that species reliant on farmland as their primary habitat are continuing to significantly decline since the falls in the 70s & 80s, whilst generalist farmland species have managed to adapt to the changes in farming practices (Defra, 2017). Farmland species in the BOS have not escaped this decline and have been affected just as much. The trends for “All Farmland” species and Specialists show a strong statistical correlation between the national and local populations. This indicates that the population dynamics of these species within the BOS is similar to England, with the possibility that specialist species are faring worse locally.

Bird Trends in the Heart of England, 1977-2016 5.1.2 Farmland Bird Index Compared to BOS Winter Random Square Survey Because the BOS breeding survey (SRSS) covers a much shorter period than the BTO surveys on which the Defra data is based, the BOS Winter Random Square Survey (WRSS) data were also analysed to see if the trends matched in earlier years. The BOS WRSS indices start in 1977, providing 40 years of data (1977-2016) compared to the 24 of SRSS. The WRSS indices exclude data for Lapwing which are in the national index, because the local BOS population is enhanced by over-wintering migrants moving into the area, which would distort the combined index. The comparison between the WRSS and BTO surveys is valid because the WRSS survey species are all resident birds that do not normally travel far during the winter period. However, large numbers of Starlings from continental Europe also winter in our area, boosting the resident populations. Whitethroat, Yellow Wagtail and Turtle Dove are not included, being summer-only species. The chart below shows the abundance of the farmland species for England (UKBI) and within the BOS (WSRSS). To enable comparison between the two datasets, the UKBI data has been scaled so that the index begins at 100 in 1977, the year that the WRSS index starts.

All Farmland Breeding Birds UKBI WRSS UKBI Trend WRSS Trend

100

Index (100 in 1977) in (100 Index 40

1986 2002 2009 1977 1978 1979 1980 1981 1982 1983 1984 1985 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2003 2004 2005 2006 2007 2008 2010 2011 2012 2013 2014 2015 2016

The chart shows there is a very close match between the BOS and English long-term trend, with a 61% decline nationally compared to 63% in the BOS for the period 1977-2016. Statistical analysis (Spearman’s test) proves there is a very strong correlation between the two datasets, even though one is measuring breeding pairs and the other over-wintering populations. This correlation possibly reflects the fact that many of the species measured are resident with minimal influx of winter populations from outside of the area. The population trend is non-linear in both cases, with a steep decline in the early period, an easing off and a recent return to decline. The trend for Generalist farmland species is similar to the SRSS trend, i.e. no significant change nationally and locally. The peak around 2006 arose from short-term increases in Greenfinch, Jackdaw and Kestrel, which have subsequently declined.

Bird Trends in the Heart of England, 1977-2016

Generalist Farmland Breeding Birds UKBI WRSS 160 150 140 130 120 110 100

90 Index (100 in 1977) in (100 Index 80

1987 2004 2014 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2005 2006 2007 2008 2009 2010 2011 2012 2013 2015 2016

The trend for Specialist farmland birds also shows a strong correlation between the BOS and England, with an 80% decline locally and 76% nationally. The chart shows that the rate of decline was much higher in the 70s & 80s in both cases. The trendline (which smooths out annual fluctuations) shows a very similar rate of decline between the two areas. Note that the trend is non-linear, as explained for the “All Farmland” case.

Specialist Farmland Breeding Birds UKBI WRSS UKBI Trend WRSS Trend 100

30 Index (100 in 1977) in (100 Index 20

1984 1992 2000 2008 2016 1978 1979 1980 1981 1982 1983 1985 1986 1987 1988 1989 1990 1991 1993 1994 1995 1996 1997 1998 1999 2001 2002 2003 2004 2005 2006 2007 2009 2010 2011 2012 2013 2014 2015 1977 5.1.3 Farmland Trends Conclusion For the species in the Defra farmland bird index, the BOS Summer and Winter Random Square surveys show a strong correlation with the national trends. These trends show that from 1977 to 2016 there has been an overall population decline of 60-70% for farmland birds within the BOS and England. The rate of decline has slowed, with only a 10-20% decline since 1993. Generalist farmland species appear to have coped better with the changes in agriculture, with no significant changes in population. Specialist species have declined significantly, though the rate of decline has reduced since 1993.

Bird Trends in the Heart of England, 1977-2016 5.2 Farmland Species Comparison The review of the farmland bird index showed a significant correlation in the trends at a national and local level for the combined index. This section investigates if the trend for each farmland species is the same locally as nationally. To do this the BTO CBC/BBS dataset (Bird Trends 2017) is compared against the equivalent BOS SRSS and WRSS data. The table lists each of the farmland species and shows the abundance trend for 1977-2015 (the WRSS survey period) for the long-term trend and 1993-2015 (the SRSS survey period) for the short-term trend. Shading is used to highlight significant changes (see Key), unshaded figures represent “no change”.

Type Species UKBI 77-15 BOS WRSS 77-15 UKBI 93-15 BOS SRSS 93-15 Generalists Greenfinch -41% -29% -40% -46% Jackdaw 138% 372% 92% 103% Kestrel -36% 196% -10% 86% Reed Bunting -31% -83% 26% 94% Rook 16% -27% -12% -42% Woodpigeon 168% -23% 50% -15% Specialists Corn Bunting -86% -99% -38% -96% Goldfinch 25% 212% 147% 176% Grey Partridge -93% -79% -48% Linnet -56% -44% 2% -61% Skylark -66% -84% -26% -35% Starling -87% -76% -70% -61% Stock Dove 83% -61% 57% 10% Tree Sparrow -95% -99% 101% -67% Whitethroat 27% 48% 23% Yellowhammer -59% -76% -37% -23% The shading indicates the amount of change using the Defra categorisation of trends over a nominal 25-year period as shown in the table below, along with the equivalent amount of change over the periods used within this report.

Trend Term Amount of change over a nominal % Change 1977-2015 % Change 1993-2015 25-year period

Strong Population increase of 100% or more Increase of 156% or more Increase of 92% or more increase Weak More than 33% but less than 100% More than 51% but less More than 30% but less increase increase than 156% increase than 92% increase

No change Between a 25% decrease and 33% Between a 39% decrease Between a 23% decrease increase and 50% increase and 30% increase

Weak less than 50% but greater than 25% less than 78% but greater less than 46% but greater decline decrease (-25% to -50%) than 39% decrease than 23% decrease

Strong population decrease of 50% or more decrease of 78% or more decrease of 46% or more decline

Key points about the Farmland species are: • Kestrels are doing better locally than nationally over the medium and long term • There has been a significant recent increase in the local Reed Bunting population though in the long term there has been a greater rate of decline. This potentially indicates a local recovery after a significant decline. • Locally Tree Sparrows are still declining whilst nationally there has been a recent increase 12

Bird Trends in the Heart of England, 1977-2016

• Linnets are declining significantly faster locally than nationally over the medium term • Greenfinch, Corn Bunting, Grey Partridge, Skylark, Starling & Yellowhammer are declining at similar rates locally and nationally Note that the BOS statistics for Corn Bunting and Tree Sparrow are subject to a greater degree of error due to the current low populations and small sample sizes in the BOS surveys and thus need to be treated with caution. 5.3 Farmland Trends Summary The chart below shows the relative trends, by category, of the farmland species over the periods 1977-2015 and 1993-2015, using the BTO smoothed CBC/BBS data (Bird Trends 2017). It gives a quick view on how many species are declining, increasing or stable. It also provides a relative comparison between the BOS and England. For 1977-2015, the number of species declining and increasing are similar between the BOS and England, but more species have a strong decline and increase in the BOS. For 1993-2015, more species are declining in the BOS, fewer are increasing. The conclusion is that it appears that farmland species are suffering more in the BOS compared to England.

Farmland Trends 100% 5% 11% 13% 90% 11% 20% 20% 7% 80% 21% 7% 70% 26% 20% 27% 60% 27% 50% 32% 27% 20% 40% 32% 20% 30%

Percentage of Speices of Percentage 21% 20% 33% 33% 26% 27% 10% 16% 0% England 1977-2015 WRSS 1977-2015 England 1993-2015 SRSS 1993-2015 WRSS 1993-2015

Strong Decline Weak Decline No Change Weak Increase Strong Increase

The Defra categorisation of trends is used, as explained in the previous section. 5.4 Conclusion The analysis of the overall farmland bird indicator trend shows that there is a strong correlation between the BOS and England as a whole. Of the species in the farmland indicator category, more species are declining than maintaining their populations. It appears that the number of species showing a significant decline since 1993 is worse in the BOS than across England. Examining the relative declines of the species that make up the farmland bird indicators shows the following local variation: • Jackdaw, Kestrel, Goldfinch and potentially Reed Bunting are doing better locally than nationally • Tree Sparrows are continuing their local decline though nationally there has been some recovery. The BTO Atlas 2007-11 (BTO, 2013) shows that the increases have been in the north of England and the losses in the south, so this fits well. To the south of the BOS Tree Sparrows have become extremely localised and dependent on conservation interventions ( (Berkshire Ornithological Club, 2015) & (Tree Sparrow Villages, 2018)). The analysis also shows that the national decline in the following species is also occurring locally: Greenfinch, Corn Bunting, Grey Partridge, Linnet, Skylark, Starling and Yellowhammer.

Bird Trends in the Heart of England, 1977-2016 6. Woodland Bird Trends The woodland coverage for England is around 9.6% of land use compared to 4.7% for the BOS (CEH: Rowland et al., 2017). Looking at a map of the BOS it is very apparent that there are very few areas with any significant sized woodlands, with most of the coverage in small plantations. It is unlikely therefore that the BOS trends for woodland birds compare well with the English situation. However, many of the species in the woodland index are very common within the BOS and include many of the species that frequent gardens. Therefore, it is important to compare the population trends of these species. 6.1 Woodland Bird Index There are 32 species in the UKBI woodland index, listed below (Defra, 2017). Species in italic are not included in the BOS SRSS index due to absence in the BOS or due to insufficient survey data on which to perform reliable statistical analysis. • Generalist: Blackbird, Blue Tit, Bullfinch, Chaffinch, Dunnock, Great Tit, Lesser Whitethroat, Long-tailed Tit, Robin, Song Thrush, Tawny Owl, Wren • Specialist: Blackcap, Chiffchaff, Coal Tit, Garden Warbler, Goldcrest, Great Spotted Woodpecker, Green Woodpecker, Jay, Lesser Redpoll, Lesser Spotted Woodpecker, Marsh Tit, Nightingale, Nuthatch, Redstart, Siskin, Sparrowhawk, Spotted Flycatcher, Tree Pipit, Treecreeper, Willow Tit, Willow Warbler, Wood Warbler The woodland bird index for England was 24% lower in 2016 than in 1970, with the greatest declines in the early 80s & early 90s: the index has been relatively stable since 1996 (Defra, 2017). 6.1.1 Woodland Bird Index for England Compared to BOS Summer Random Square Survey The chart below shows the breeding abundance trend for species in the woodland bird index for the period 1993- 2016 for England (UKBI) and the BOS (SRSS).

All Woodland Breeding Birds UKBI SRSS UKBI Trend SRSS Trend 110

100

Index (100 in 1993) in (100 Index 60

50 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016

The graph shows that there is little correlation between the trend for England and the BOS. It does show there has been a decline in woodland species in the BOS of around 32% compared to 10% nationally. For many of the species in the BOS there was a decline to 2002 followed by a recovery to 2010 and then a subsequent decline. This trend warrants further exploration to understand the reasons why. The trend for Generalist woodland species shows a 15% increase over the period for England and a 19% decline locally. Yet again, the BOS trend format follows that of the “All Woodland” index, with a peak around 2010 followed by decline. There is no correlation between the BOS and England trend.

Bird Trends in the Heart of England, 1977-2016

Generalist Woodland Breeding Birds UKBI SRSS UKBI Trend SRSS Trend 120 115 110 105 100 95 90

85 Index (100 in 1993) in (100 Index 80 75 70 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016

The trend for Specialist woodland species shows a 21% decline for England and 42% locally. The BOS trend shows a more pronounced “wave” compared to the Generalist species, with the 2010 recovery not getting back to 100, followed by a sharp decline.

Specialist Woodland Breeding Birds UKBI SRSS UKBI Trend SRSS Trend 110

100

60 Index (100 in 1993) in (100 Index 50

40 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016

6.1.2 Woodland Bird Index for England Compared to BOS Winter Random Square Survey The BOS breeding survey (SRSS) only started in 1991, so the BOS winter survey (WRSS) data were analysed to see if the trends matched in earlier years. The WRSS does not have data for the following migratory species in the Woodland Index: Lesser Whitethroat, Blackcap, Chiffchaff, Garden Warbler, Nightingale, Redstart, Spotted Flycatcher, Tree Pipit, Willow Warbler and Wood Warbler. Compared to the BOS SRSS, the winter survey does include data for Lesser Redpoll, Lesser Spotted Woodpecker and Siskin. Thus, unlike the Farmland bird index comparison, comparing the BOS WRSS data against the English Woodland Index uses a more restricted set of species. Care is therefore needed when comparing the trends due to the different mix of species. However, it is instructive do so because it compares the population trends of the local non-migratory woodland bird species. The chart below shows the abundance of the woodland species for England (UKBI) and within the BOS (WSRSS). To enable comparison between the two datasets, the UKBI data has been scaled so that the index begins at 100 in 1977, the year that the WRSS index starts. 15

Bird Trends in the Heart of England, 1977-2016

All Woodland Breeding Birds UKBI WRSS UKBI Trend WRSS Trend 140 130 120 110 100 90 80

70 Index (100 in 1977) in (100 Index 60 50

1977 1988 1999 2010 1979 1980 1981 1982 1983 1984 1985 1986 1987 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2011 2012 2013 2014 2015 2016 1978 Unlike the Farmland Bird Index, there is not a direct correlation between the BOS winter survey data and the English Woodland Bird Index over the long-term. The national trend shows a slow decline, whereas locally there was an upturn in 2001-2004 back to former levels, similar to that detected in the SRSS. Unlike the non-linear trend for farmland birds, the national woodland trend is more linear. Nationally there has been a 31% population decline in the 40-year period 1977-2016, compared to 22% locally. The trends for Generalist woodland species are similar to that of the whole Woodland index. Nationally there has been no significant population change for Generalist species, whereas locally there has been a 28% decline over the period 1977-2016. There is no correlation between the BOS trend and that for England.

Generalist Woodland Breeding Birds UKBI WRSS UKBI Trend WRSS Trend 110

100

70 Index (100 in 1977) in (100 Index 60

1995 2000 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1996 1997 1998 1999 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 1977 The trend for Specialist woodland birds reveals a different picture. Nationally there has been a 45% population decline compared to a 16% decline locally. The chart shows that there is no correlation between the BOS and England trends.

Bird Trends in the Heart of England, 1977-2016

Specialist Woodland Breeding Birds UKBI WRSS UKBI Trend WRSS Trend 180 170 160 150 140 130 120 110 100

90 Index (100 in 1977) in (100 Index 80 70 60 50

1990 2009 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2010 2011 2012 2013 2014 2015 2016 1977 Unlike the case for Farmland species, none of the woodland trends are correlated between the BOS winter survey and the English index. This disparity is due to the significant differences in the population trends of the individual species that constitute the Woodland species. Some of the species have undergone significant population increases (e.g. Blackcap & Chiffchaff) whilst others have declined significantly (e.g. Lesser Redpoll & Willow Tit). The trends for each species are reviewed in the next section.

The Farmland index showed minimal change in the Generalist species population trend, both locally and nationally, but for Woodland species both groups show a local population decline.

Bird Trends in the Heart of England, 1977-2016 6.2 Woodland Species Comparison The review of the woodland birds index showed a significant difference between England and the BOS. This section compares the trend for each species based on the BTO CBC/BBS dataset (Bird Trends 2017). The table below lists each of the woodland species and shows the abundance trend for 1977-2015 (the WRSS survey period) and for 1993-2015 (the SRSS survey period), with shading to reflect significant changes.

Type Species UKBI 77-15 BOS WRSS 77-15 UKBI 93-15 BOS SRSS 93-15 Generalists Blackbird -10% -16% 14% -30% Blue Tit 5% 8% 8% 10% Bullfinch -50% -65% 9% 1% Chaffinch 10% -36% -2% -30% Dunnock -27% -41% 22% -15% Great Tit 56% 13% 29% 19% Lesser Whitethroat -3% 18% -14% Long-tailed Tit 67% 138% 33% -11% Robin 59% 8% 36% 3% Song Thrush -35% -73% 24% -10% Tawny Owl -48% -42% Wren 36% -27% 17% -28% Specialists Blackcap 244% 130% 52% Chiffchaff 251% 161% 1% Coal Tit 4% 113% 24% -42% Garden Warbler 7% -21% -71% Goldcrest -21% 57% 63% -21% Great Spotted Woodpecker 116% 100% 127% 111% Green Woodpecker 101% 55% 61% 52% Jay -9% 21% 8% 86% Lesser Redpoll -97% -95% -41% Marsh Tit -60% 25% -43% -42% Nightingale -82% -62% Nuthatch 168% 519% 122% 120% Redstart 125% 39% Sparrowhawk 58% 492% -17% -76% Spotted Flycatcher -89% -53% -75% Tree Pipit -83% -60% Treecreeper -16% -16% 2% -68% Willow Tit -91% -98% -74% Willow Warbler -64% -33% -81% The shading indicates the amount of change (see section 5.2 for a definition of Defra categorisation of trends): • Strong Increase • Weak Increase • Weak Decline • Strong Decline Species that are doing well nationally are: Blackcap, Chiffchaff, Goldcrest, G.S. Woodpecker, Green Woodpecker and Nuthatch. In the BOS, the list includes Jay but not Chiffchaff and Goldcrest. 18

Bird Trends in the Heart of England, 1977-2016 Species that are declining fastest nationally are Marsh Tit, Nightingale, Spotted Flycatcher, Tree Pipit & Willow Tit. These species are also declining in the BOS along with Garden Warbler, Treecreeper and Willow Warbler. Overall, there seems to be a basic correlation for the overall population change for most of the individual woodland species between England and the BOS, which is not apparent when comparing the overall woodland bird index. However, the way the populations are changing (the trends) is significantly different. 6.3 Woodland Trends Summary The chart below shows the relative trends, by category, of the woodland species over the periods 1977-2015 and 1993-2015, using the BTO smoothed CBC/BBS data (Bird Trends 2017). It gives a quick view on how many species are declining, increasing or stable. It also provides a relative comparison between the BOS and England. For 1977-2015, the BOS trend shows a more stable population, with fewer species showing a strong decline. For 1993-2015, the BOS SRSS trend shows the opposite, with more species than England showing a weak or strong decline, though the overwintering population has not been so affected. This indicates that locally, breeding woodland species are declining more rapidly than in England. Compared to the farmland birds trend, there are fewer woodland species undergoing a strong decline in the 1993- 2015 period, both nationally and locally.

Woodland Trends 100% 8% 10% 9% 13% 9% 90% 12% 80% 23% 23% 16% 23% 70%

60% 42%

50% 39% 45% 45% 45% 40%

30% Percentage of Species of Percentage 19% 13% 20% 13% 14% 9% 10% 16% 19% 9% 13% 14% 0% England 1977-2015 WRSS 1977-2015 England 1993-2015 SRSS 1993-2015 WRSS 1993-2015

Strong Decline Weak Decline No Change Weak Increase Strong Increase

6.4 Woodland Trends Conclusion Unlike farmland species, the trends for the birds in the woodland index for England are different from those in the BOS. Locally, many of the species suffered a decline to 2002, followed by a recovery to 2010 and then a subsequent decline. The national trend for woodland species shows a slower decline compared to farmland species. However, there are several specialist woodland species which are undergoing significant declines, both nationally and locally. Overall, it appears that the net change in populations of most species in the woodland index are similar nationally and locally, i.e. the species undergoing increases and declines are very similar.

Bird Trends in the Heart of England, 1977-2016 7. Species Status This section provides detailed statistical analysis of all of the BOS species within the UKBI farmland and woodland categories. 7.1 Format of Each Species Report Each species is listed in the BOS 2017 taxonomic order. Each species is introduced with: • English name and scientific name (as of 2017) • Status of the species within the BOS (from the BOS Systematic List) and the BoCC 4 amber/red status • UKBI Category of the species Statistical information is provided, depending on the availability of the data, in three categories: • Long and short-term population change in England and BOS: the % change over the periods 1977-2015 and 1993-2015 along with a categorisation of the trend o The Defra categorisation of the species population trend is used, as defined in section 5.2 • Abundance chart in England and BOS from 1977-2015: o Based on the UKBI dataset and BOS SRSS & WRSS indices • Distribution charts within the BOS: o Distribution is calculated as % of the 1km squares within the BOS study area that each species is found in, based on the Summer & Winter random square surveys. See Appendix (9.3.1) for further details on the statistical method used. o Number of 1km OS grid squares the species was observed in, from the monthly sightings, over a 5- year period (the BOS covers 1200km2). This is presented where all records for a species are requested by the BOS in our ‘Guidance for Observers’. Note that for some species the status has changed, with not all records being requested in earlier years. This is noted for each species, where known. The statistical data for England comes from the BTO CBC/BBS dataset (The Breeding Bird Survey 2016, 2017), this being the dataset behind both the Defra and JNCC reports. The BTO 2016 dataset omits the final year, so analysis is up to 2015. A statement is provided stating how correlated the SRSS and WRSS trends are compared to the English trend. Correlation is a statistical measure that shows how related two sets of values are. A strong correlation is assigned if the trends are very similar, weak if there is some similarity. If the BOS index is not correlated, then the local population change is different from England. The Abundance charts use an index value of 100 for the year 1993, allowing comparative plotting of the UKBI index against the BOS SRSS and WRSS indices. Thus, if the BOS line is below that of the UKBI line, then it means that populations within the BOS have declined more than in England. For the Abundance and Distribution charts, a trend line has been plotted (dotted lines) if there is a statistically reliable linear or simple curved trend. Where a trend line is shown, it should only be used as a guide within the corresponding data range and ignored where it extends beyond the data – they are not an indication or prediction of future or past population trends. Due to the relatively small number of surveys carried out by the BOS, the index values can vary significantly from year to year, making it difficult in some cases to fit a trend line with any degree of statistical validity. In these cases, a trendline is not shown. The general approach is to try and choose a trend line that matches the overall population change, using the R-squared statistical test. See Appendix 9.4 for details on the trend line fitting process. A linear trendline shows if there is a fairly regular increase or decrease in a population. A curved line is shown when the historic or current trend is greater or lesser, i.e. the trend is varying over time.

Bird Trends in the Heart of England, 1977-2016 7.2 GREY PARTRIDGE Perdix perdix Not Scarce resident; Red UKBI Category: Farmland – Specialists There are insufficient Grey Partridge records from the BOS breeding survey (SRSS) to enable direct comparison with the English trend. The BOS winter survey (WRSS) provides a way to compare the trends but needs to be treated with some caution due to the release of some birds for game shooting. 7.2.1 Abundance Trends Period England Trend WRSS Trend 1977-2015 -93% Strong decline -79% Strong decline 1993-2015 -48% Strong decline -43% Weak decline Grey Partridge have declined significantly over the period, both nationally and locally. The WRSS is weakly correlated with the English trend, though the overall rate of decline is very similar. 7.2.2 Abundance Chart

Grey Partridge Abundance 1977-2015 UKBI WRSS SRSS 750 UKBI Trend WRSS Trend 700 650 600 550 500 450 400 350

Index (100 in 1993) in (100 Index 300 250 200 150 100 50 0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

Grey Partridge declined rapidly in the 70s & 80s, followed by a subsequent period of slower decline. The BOS trend is similar to that for England. The erratic profile of the SRSS index is due to the low breeding density. Since 2006 breeding has not been detected at all in several survey years, making it difficult to determine an accurate estimate of the breeding density within the BOS. 7.2.3 Distribution Chart The low population of Grey Partridge within the BOS is probably one reason for the erratic distribution recorded in the BOS surveys, though the overall trend is one of decline. Monthly sightings are similar to the WRSS, suggesting a distribution of 5-10% across the BOS, a significant decline that has occurred over the last 30 years.

Bird Trends in the Heart of England, 1977-2016

Grey Partridge BOS Distribution 1977-2015 WRSS SRSS WRSS Trend 35

10 % of 1km Survey Squares Survey 1km of % 5

0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

Grey Partridge BOS Sightings Distribution 160 140 120 100 80 60

No. of 1km Squares 1km of No. 40 20 0 1982-86 1987-91 1992-96 1997-01 2002-06 2007-11 2012-16

7.3 SPARROWHAWK Accipiter nisus Fairly numerous resident UKBI Category: Woodland – Specialists 7.3.1 Abundance Trends Period England Trend SRSS Trend WRSS Trend 1977-2015 58% Weak increase 492% Strong increase 1993-2015 -17% No change -76% Strong decline -9% No change Nationally, Sparrowhawk have increased in the long term, but have declined in the last 21 years, which is roughly mirrored by the BOS WRSS results. The SRSS shows a more significant decline, with an unexplained peak around 2009/10.

Bird Trends in the Heart of England, 1977-2016 7.3.2 Abundance Chart Sparrowhawk Abundance 1977-2015 UKBI WRSS SRSS UKBI Trend WRSS Trend 220 200 180 160 140 120 100

80 Index (100 in 1993) in (100 Index 60 40 20 0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The abundance chart shows the rise and decline of Sparrowhawk nationally and locally in the WRSS. The BOS trend roughly follows that for England. The population increase in the 1970s/80s was linked to the impact of DDT and its subsequent withdrawal. By 2007 Sparrowhawks were more numerous in the BOS than at any time since the BOS was formed in 1952 (Easterbrook, 2013). 7.3.3 Distribution Chart

Sparrowhawk Distribution 1977-2015 40 SRSS WRSS SRSS Trend WRSS Trend

10 % of 1km Survey Squares Survey 1km of %

0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The distribution chart shows that Sparrowhawk distribution has hardly changed in the BOS winter surveys since recovering from the impact of DDT in the 1970s, occurring in around 15% of 1km squares. The SRSS shows a lower distribution than the WRSS, which might be due to the fact that detecting breeding can be difficult for this species. The BOS monthly records show a slow decline in distribution, but it is observed in 25% of the region.

Bird Trends in the Heart of England, 1977-2016

Sparrowhawk BOS Sightings Distribution 500 450 400 350 300 250 200 150

No. of 1km Squares 1km of No. 100 50 0 1982-86 1987-91 1992-96 1997-01 2002-06 2007-11 2012-16

7.4 KESTREL Falco tinnunculus Fairly numerous resident; Amber UKBI Category: Farmland – Generalists 7.4.1 Abundance Trends Period England Trend SRSS Trend WRSS Trend 1977-2015 -36% No change 196% Strong increase 1993-2015 -10% No change 86% Weak increase 93% Strong increase The SRSS and WRSS are not correlated to the English trend, showing a population increase, which is a positive sign for the BOS. 7.4.2 Abundance Chart

Kestrel Abundance 1977-2015 UKBI WRSS SRSS UKBI Trend WRSS Trend SRSS Trend 400

350

300

250

200

150 Index (100 in 1993) in (100 Index 100

0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The BOS SRSS and WRSS show a significant population increase in the 2000s, unlike the national decline. The BOS Annual Breeding Surveys (ABSS) for Kestrels of 1986 and 2012 (Brownett A. , Kestrel Survey 2012) however, did not show any significant change in the breeding population. It is possible that the winter population is supplemented by birds from outside of the area (Easterbrook, 2013).

Bird Trends in the Heart of England, 1977-2016 7.4.3 Distribution Charts

Kestrel Distribution 1977-2015 SRSS WRSS SRSS Trend WRSS Trend 60

10 % of 1km Survey Squares Survey 1km of %

0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015 2017 The SRSS and WRSS charts show that after an increase, Kestrel distribution is possibly declining.

Kestrel BOS Sightings Distribution 700 600 500 400 300

200 No. of 1km Squares 1km of No. 100 0 1982-86 1987-91 1992-96 1997-01 2002-06 2007-11 2012-16

Kestrel sightings only started being recorded fully in the 2000s, so the low count of sightings prior to that does not accurately reflect the true distribution. The current records (2012-2016) come from 50% of the BOS territory, slightly more than the SRSS & WRSS records, showing that Kestrels are widely distributed across the BOS. 7.5 LAPWING Vanellus vanellus Not Scarce resident and Winter Visitor; Red UKBI Category: Farmland – Specialists 7.5.1 Abundance Trends Lapwing breed in such low numbers that they are not accurately recorded in the BOS breeding survey. Therefore, only the BOS winter survey trend is shown. The local Lapwing population is enhanced over winter by birds arriving from other regions, so the population being measured is not wholly local, which will distort the local trends analysis. Period England Trend WRSS Trend 1977-2015 -60% Weak decline -97% Strong decline 1993-2015 22% No change -92% Strong decline The WRSS is strongly correlated with the English trend, with a greater decline locally than nationally.

Bird Trends in the Heart of England, 1977-2016 7.5.2 Abundance Chart Lapwing Abundance 1977-2015 UKBI WRSS SRSS UKBI Trend WRSS Trend 350

300

250

200

150

Index (100 in 1993) in (100 Index 100

0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

Nationally, Lapwing populations are not declining as fast as they were, but within the BOS it appears that the decline is still continuing. The erratic nature of the SRSS index is a result of the low breeding density of the species, with many survey squares not detecting breeding Lapwings. Breeding pairs were only detected in 70% of the survey years and in 5% of survey squares. The BOS ABSS of Lapwings in 1980 and 2006 (Brownett A. , Lapwing Survey 2006) detected a decline in the breeding population of 73%, an annual rate similar to that detected by the WRSS. The decline was not even over the area, with some 10km squares being affected relatively more than others. The majority of nest sites were on arable land, so the switch to winter sown cereals is suspected as a significant factor since the first survey detected a preference for spring-sown cereals. The survey detected that breeding attempts were less successful in 2006 than in 1980. 7.5.3 Distribution Chart Lapwing Distribution 1977-2015 WRSS SRSS WRSS Trend 80

% of 1km Survey Squares Survey 1km of % 10

0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The winter distribution shows a significant decline from widespread occurrence to around 10% of the survey squares. This is backed up by the monthly sightings (note that in the 80s only flocks >50 were recorded). The significant difference between winter and summer distribution is due to an incoming over-wintering population. The decline in the winter population is indicative of the national decline in lapwing, i.e. a drop in over-wintering birds. 26

Bird Trends in the Heart of England, 1977-2016

Lapwing BOS Sightings Distribution 300 250 200 150 100

No. of 1km Squares 1km of No. 50 0 1982-86 1987-91 1992-96 1997-01 2002-06 2007-11 2012-16

7.6 STOCK DOVE Columba oenas Numerous resident; Amber UKBI Category: Farmland – Specialists 7.6.1 Abundance Trends Period England Trend SRSS Trend WRSS Trend 1977-2015 83% Weak increase -61% Weak decline 1993-2015 57% Weak increase 10% No change -7% No change The SRSS is weakly correlated with the English trend, with a slight increase in population. The WRSS is not correlated, showing a sharp decline from former levels. 7.6.2 Abundance Chart Stock Dove Abundance 1977-2015 UKBI WRSS SRSS UKBI Trend WRSS Trend SRSS Trend 240 220 200 180 160 140 120

Index (100 in 1993) in (100 Index 100 80 60 40 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The local breeding abundance trend is similar to England, but the WRSS shows a different profile, the reasons for which are not currently known.

Bird Trends in the Heart of England, 1977-2016 7.6.3 Distribution Chart

Stock Dove Distribution 1977-2015 SRSS WRSS 90 85 80 75 70 65 60 55

50 % of 1km Survey Squares Survey 1km of % 45 40 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015 2017

The slight rise in the breeding (SRSS) trend matches the English population trend and shows a widespread distribution in the BOS. 7.7 WOODPIGEON Columba palumbus Abundant resident UKBI Category: Farmland – Generalists 7.7.1 Abundance Trends Period England Trend SRSS Trend WRSS Trend 1977-2015 168% Strong increase -15% No change 1993-2015 50% Weak increase -15% No change -16% No change In England, Woodpigeon have shown a year-on-year population increase. This has not been detected within the BOS, the SRSS actually showing a weak decline. 7.7.2 Abundance Chart Woodpigeon Abundance 1977-2015 UKBI WRSS SRSS UKBI Trend WRSS Trend SRSS Trend

160

140

120

100

60 Index (100 in 1993) in (100 Index 40

0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The increase in Woodpigeon population is clearly shown for England, whilst the BOS SRSS shows a small decline and the WRSS shows a stable population. 28

Bird Trends in the Heart of England, 1977-2016 7.7.3 Distribution Woodpigeon are one of the most widely distributed species in the BOS, being observed in 100% of survey squares. 7.8 GREEN WOODPECKER Picus viridis Fairly numerous resident UKBI Category: Woodland – Specialists 7.8.1 Abundance Trends Period England Trend SRSS Trend WRSS Trend 1977-2015 101% Weak increase 55% Weak increase 1993-2015 61% Weak increase 52% Weak increase 85% Weak increase The Green Woodpecker population has increased over the survey periods, both nationally and locally. The SRSS and WRSS are not directly correlated with the national index, showing a different pattern for the local population increase. 7.8.2 Abundance Chart

Green Woodpecker Abundance 1977-2015 UKBI WRSS SRSS UKBI Trend WRSS Trend SRSS Trend 220 200 180 160 140 120 100

80 Index (100 in 1993) in (100 Index 60 40 20 0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The abundance chart shows the national and local population increase, though on different timescales, the BOS increase coming later. The national trend indicates that the population peaked in the mid-2000s and is no longer increasing, which appears to be the case locally as well. The ABSS of 1976 and 2002 (Brownett A. , Green Woodpecker Survey 2002) showed that there was a population increase over this period and that breeding was directly correlated to the presence of permanent pasture.

Bird Trends in the Heart of England, 1977-2016 7.8.3 Distribution Chart

Green Woodpecker Distribution 1977-2015 100 SRSS WRSS SRSS Trend WRSS Trend 90

% of 1km Survey Squares Survey 1km of % 20

0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The distribution chart shows that Green Woodpeckers have spread locally and the surveys indicate that they now occupy over 50% of the region.

7.9 GREAT SPOTTED WOODPECKER Dendrocopos major Numerous resident with extensive distribution UKBI Category: Woodland – Specialists 7.9.1 Abundance Trends Period England Trend SRSS Trend WRSS Trend 1977-2015 116% Weak increase 100% Weak increase 1993-2015 127% Strong increase 111% Strong increase 221% Strong increase The SRSS and WRSS are both strongly correlated with the English trend, with a strong increase in population over recent years.

Bird Trends in the Heart of England, 1977-2016 7.9.2 Abundance Chart

Great Spotted Woodpecker Abundance 1977-2015 UKBI WRSS SRSS UKBI Trend WRSS Trend SRSS Trend 500 450 400 350 300 250 200

Index (100 in 1993) in (100 Index 150 100 50 0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The chart shows the long-term increase in Great Spotted Woodpeckers locally and nationally. The major increase detected by the WRSS in the 2000s is not matched nationally and seems to be quickly declining from its peak. The BOS ABSS of 1975 and 2000 showed a threefold increase (Brownett A. , Great Spotted Woodpecker Survey 2000) in the breeding population. In the original survey it was speculated that the population would be impacted due to the widespread impact of Dutch elm disease removing one of their favoured breeding sites. Subsequent analysis (Easterbrook, 2013) has shown that the species has moved into farmland, especially where there are hedgerows with mature trees, and into built-up areas. 7.9.3 Distribution Chart

Great Spotted Woodpecker Distribution 1977-2015 100 SRSS WRSS 90 SRSS Trend WRSS Trend 80

30 % of 1km Survey Squares Survey 1km of % 20

0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The distribution chart shows the steady increase in Great Spotted Woodpecker across the region. They are now present in most survey squares.

Bird Trends in the Heart of England, 1977-2016 7.10 JAY Garrulus glandarius Fairly numerous resident with widespread distribution UKBI Category: Woodland – Specialists 7.10.1 Abundance Trends Period England Trend SRSS Trend WRSS Trend 1977-2015 -9% No change 21% No change 1993-2015 8% No change 86% Weak increase -2% No change Nationally the population has not changed but locally there has been a recent increase. 7.10.2 Abundance Chart

Jay Abundance 1977-2015 UKBI WRSS SRSS UKBI Trend WRSS Trend SRSS Trend 200 180 160 140 120 100 80

60 Index (100 in 1993) in (100 Index 40 20 0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The abundance chart shows that nationally there has been no change in Jay numbers, but there has been a significant local increase in the last 10 years. 7.10.3 Distribution Chart

Jay Distribution 1977-2015 SRSS WRSS SRSS Trend WRSS Trend 50

10 % of 1km Survey Squares Survey 1km of %

0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The distribution chart shows an increase since the late 90s in both the summer and winter surveys, being located in around 50% of survey squares.

Bird Trends in the Heart of England, 1977-2016 7.11 JACKDAW Corvus monedula Abundant resident with widespread distribution UKBI Category: Farmland – Generalists 7.11.1 Abundance Trends Period England Trend SRSS Trend WRSS Trend 1977-2015 138% Weak increase 372% Strong increase 1993-2015 92% Weak increase 103% Strong increase 45% Weak increase The SRSS is weakly correlated to the English trend, the WRSS is strongly correlated, both showing a significant increase in population. 7.11.2 Abundance Chart Jackdaw Abundance 1977-2015 UKBI WRSS SRSS UKBI Trend WRSS Trend SRSS Trend 260 240 220 200 180 160 140 120 100

80 Index (100 in 1993) in (100 Index 60 40 20 0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The abundance chart shows there has been a steady increase in Jackdaw populations, locally and nationally, with no sign of the increase halting. It is possible that this increase is due to their generalist feeding habits and exploitation of suburban chimneys for nesting (Easterbrook, 2013). 7.11.3 Distribution Chart

Jackdaw Distribution 1977-2015 SRSS WRSS SRSS Trend WRSS Trend

50 % of 1km Survey Squares Survey 1km of %

40 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

Jackdaws have spread in the region, now occupying 80-90% of the survey squares, up from 50%. 33

Bird Trends in the Heart of England, 1977-2016 7.12 ROOK Corvus frugilegus Abundant resident with extensive distribution UKBI Category: Farmland – Generalists 7.12.1 Abundance Trends Period England Trend SRSS Trend WRSS Trend 1977-2015 -27% No change 1994-2015 -12% No change -36% Weak decline -42% Weak decline Note: The Rook was not surveyed as part of the BTO CBC, so there is no long-term trend value. The short-term period starts in 1994 when the BTO BBS started. The SRSS and WRSS are not correlated with the English trend, though all 3 indexes indicate a long-term decline in populations. The BOS conducted specific surveys of Rooks in 1975, 1991, 1998 and 2006 as part of the BOS Annual Breeding Bird Surveys (ABSS). The first 3 surveys indicated a stable population, whilst the 2006 survey detected evidence of an increase of 9% in the population (Brownett A. , Rook Survey 2006). The SRSS trend however shows a significant decline from a peak in 2006. 7.12.2 Abundance Chart

Rook Abundance 1977-2015 BBS WRSS SRSS BBS Trend WRSS Trend 140

120

100

Index (100 in 1993) in (100 Index 40

0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The fluctuations in the SRSS index could be due to the uneven distribution of rookeries and the fact that each year only a small percentage of the BOS is surveyed. As noted above, the ABSS indicated a stable population in the period 1975-1998.

Bird Trends in the Heart of England, 1977-2016 7.12.3 Distribution Chart

Rook Distribution 1977-2015 SRSS WRSS SRSS Trend WRSS Trend 90 80 70 60 50 40 30

20 % of 1km Survey Squares Survey 1km of % 10 0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The distribution chart shows that Rooks are well distributed across the BOS with no major change. 7.13 GOLDCREST Regulus regulus Numerous resident UKBI Category: Woodland – Specialists 7.13.1 Abundance Trends Period England Trend SRSS Trend WRSS Trend 1977-2015 -21% No change 57% Weak increase 1993-2015 63% Weak increase -21% No change 78% Weak increase Goldcrest populations fluctuate, in part due to adverse weather. This makes it difficult to detect trends or correlate the BOS population with the English index. 7.13.2 Abundance Chart Goldcrest Abundance 1977-2015 UKBI WRSS SRSS UKBI Trend 350

300

250

200

150

100 Index (100 in 1993) in (100 Index 50

0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The abundance chart shows the periodic population fluctuations, which in part are due to colder than average winters (Easterbrook, 2013). There are no obvious trends given the degree of variance, indicating that the population over the long term is relatively stable. 35

Bird Trends in the Heart of England, 1977-2016 7.13.3 Distribution Chart Goldcrests are widely distributed across the BOS and the trend indicates distribution has increased over the survey periods.

Goldcrest Distribution 1977-2015 SRSS WRSS SRSS Trend WRSS Trend 60

% of 1km Survey Squares Survey 1km of % 10

0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

7.14 BLUE TIT Cyanistes caeruleus Abundant resident with extensive distribution UKBI Category: Woodland – Generalists 7.14.1 Abundance Trends Period England Trend SRSS Trend WRSS Trend 1977-2015 5% No change 8% No change 1993-2015 8% No change 10% No change 38% Weak increase Locally, the Blue Tit population has fluctuated, so that the SRSS and WRSS indices are not correlated with the English index. However, the overall population trend is the same, i.e. no long-term significant change. 7.14.2 Abundance Chart

Blue Tit Abundance 1977-2015 UKBI WRSS SRSS UKBI Trend WRSS Trend SRSS Trend 180

160

140

120

100 Index (100 in 1993) in (100 Index 80

60 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The abundance chart shows a local population decline in the late 90s followed by a recovery back to previous levels. Feeding in gardens during the winter and the provision of nest boxes in gardens may have helped to boost their population (Easterbrook, 2013).

Bird Trends in the Heart of England, 1977-2016 7.14.3 Distribution Blue Tits are amongst the most widely distributed species in the BOS, being observed in practically all 1km2 squares. 7.15 GREAT TIT Parus major Abundant resident with extensive distribution UKBI Category: Woodland – Generalists 7.15.1 Abundance Trends Period England Trend SRSS Trend WRSS Trend 1977-2015 56% Weak increase 13% No change 1993-2015 29% No change 19% No change 27% No change The SRSS is correlated with the English trend, with an increase in abundance similar to England. The WRSS is not correlated. 7.15.2 Abundance Chart

Great Tit Abundance 1977-2015 UKBI WRSS SRSS UKBI Trend WRSS Trend SRSS Trend 220

200

180

160

140

120

Index (100 in 1993) in (100 Index 100

40 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The abundance chart shows the gradual increase in Great Tit populations, locally and nationally. The local winter population shows a significant periodic fluctuation not shown nationally. The start and end points of the WRSS index are similar to the national index, so the overall population status is similar. Like the Blue Tit, the species has taken advantage of garden feeding and nesting opportunities (Easterbrook, 2013), though it tends to favour more wooded areas compared to Blue Tits, which might explain why it is not as quite as abundant. 7.15.3 Distribution Great Tits are amongst the most widely distributed species in the BOS, being observed in practically all 1km2 squares. 7.16 COAL TIT Periparus ater Numerous resident with widespread distribution UKBI Category: Woodland – Specialists 7.16.1 Abundance Trends Period England Trend SRSS Trend WRSS Trend 1977-2015 4% 113% Weak increase 1993-2015 24% No change -42% Weak decline 18% No change Nether the SRSS or WRSS indices are correlated with the English index. 37

Bird Trends in the Heart of England, 1977-2016 7.16.2 Abundance Chart

Coal Tit Abundance 1977-2015 UKBI WRSS SRSS UKBI Trend WRSS Trend SRSS Trend

160

140

120

100

60 Index (100 in 1993) in (100 Index 40

0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The abundance chart shows a slight increase in abundance nationally, which is matched by the BOS winter abundance survey. The breeding population decline in the BOS, noted in section 7.16.1, appears to be due to high levels of abundance noted in the first years of the SRSS. Since that time the abundance has been stable or even increasing, so there is probably no cause for concern. The species is affected by harsh winters, but is able to recover its numbers relatively quickly (Easterbrook, 2013). 7.16.3 Distribution Chart

Coal Tit Distribution 1977-2015 SRSS WRSS SRSS Trend WRSS Trend

20 % of 1km Survey Squares Survey 1km of % 10

0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The distribution chart shows that Coal Tits appear to have become more widespread across the BOS, with breeding being recorded in over 35% of the survey squares.

Bird Trends in the Heart of England, 1977-2016 7.17 WILLOW TIT Poecile montana Scarce resident; Red UKBI Category: Woodland – Specialists 7.17.1 Abundance Trends Period England Trend SRSS Trend WRSS Trend 1977-2015 -91% Strong decline -98% Strong decline 1993-2015 -74% Strong decline -90% Strong decline -94% Strong decline Willow Tits have declined significantly over the survey periods, nationally and locally. The SRSS and WRSS are both correlated with the English trend, indicating that the local and national trends are similar. 7.17.2 Abundance Chart

Willow Tit Abundance 1977-2015 UKBI WRSS SRSS UKBI Trend WRSS Trend SRSS Trend

400 350 300 250 200

150 Index (100 in 1993) in (100 Index 100 50 0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The abundance chart shows the dramatic decline in the Willow Tit population and the close link between the BOS and national trend. 7.17.3 Distribution Chart

Willow Tit Distribution 1977-2015 SRSS WRSS SRSS Trend WRSS Trend 30

% of 1km Survey Squares Survey 1km of % 5

0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015 Willow Tit distribution has declined in line with the abundance decline. They are now a very scarce and localised species within the BOS. 39

Bird Trends in the Heart of England, 1977-2016 7.18 MARSH TIT Poecile palustris Fairly numerous resident with widespread distribution; Red UKBI Category: Woodland – Specialists 7.18.1 Abundance Trends Period England Trend SRSS Trend WRSS Trend 1977-2015 -60% Weak decline 25% No change 1993-2015 -43% Weak decline -42% Weak decline 16% No change Marsh Tit are declining nationally. Locally the SRSS shows a decline of a similar amount, but the WRSS indicates a more stable population. Neither the SRSS nor WRSS are directly correlated with the national index – the local variations not being apparent in the national index. 7.18.2 Abundance Chart Marsh Tit Abundance 1977-2015 UKBI WRSS SRSS UKBI Trend WRSS Trend SRSS Trend 180

160

140

120

100

60 Index (100 in 1993) in (100 Index 40

0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The abundance chart shows that the pattern of local population changes is different from the national situation, though both show a decline. The WRSS shows periodic population increases followed by subsequent decreases, with a potential trend of a slow decline. The ABSS of 1982 and 2008 (Brownett A. , Marsh/Willow Tit Survey 2008) registered a significant decline in breeding density.

Bird Trends in the Heart of England, 1977-2016 7.18.3 Distribution Chart

Marsh Tit Distribution 1977-2015 SRSS WRSS SRSS Trend WRSS Trend 35

10 % of 1km Survey Squares Survey 1km of % 5

0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The distribution chart shows that overall the distribution has not significantly changed, with around 20% of survey squares reporting presence. 7.19 SKYLARK Alauda arvensis Numerous resident; Red UKBI Category: Farmland – Specialists 7.19.1 Abundance Trends Period England Trend SRSS Trend WRSS Trend 1977-2015 -66% Weak decline -84% Strong decline 1993-2015 -26% Weak decline -35% Weak decline -59% Strong decline The SRSS is not statistically correlated with the English index, whilst the WRSS is strongly correlated. However, the abundance charts show a general similarity in the abundance trends in the BOS and England, i.e. a declining population. 7.19.2 Abundance Chart

Skylark Abundance 1977-2015 UKBI WRSS SRSS UKBI Trend WRSS Trend SRSS Trend 260 240 220 200 180 160 140 120 100

Index (100 in 1993) in (100 Index 80 60 40 20 0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

Bird Trends in the Heart of England, 1977-2016 The trends show that there was a sharp decline followed by a period of relative stability in populations, before falling again in recent years. The local and national trends are closely correlated. The decline in the 70s/80s is suspected to be directly related to a reduction in their preferred food sources (Easterbrook, 2013). 7.19.3 Distribution Charts Skylark Distribution 1977-2015 SRSS WRSS SRSS Trend WRSS Trend 100

50 % of 1km Survey Squares Survey 1km of % 40

30 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

Unlike the abundance trends, the distribution trend is relatively constant, showing that Skylarks are still occupying territories across the BOS area. This is backed up by increasing distribution as measured by the monthly sightings, meaning that densities are decreasing. At the start of the recording period, the minimum recording level was a flock size of 50, but this is now down to 5. This explains the seemingly improved distribution in the chart below.

Skylark BOS Sightings Distribution 180 160 140 120 100 80 60

No. of 1km Squares 1km of No. 40 20 0 1982-86 1987-91 1992-96 1997-01 2002-06 2007-11 2012-16

7.20 LONG-TAILED TIT Aegithalos caudatus Fairly numerous resident with extensive distribution UKBI Category: Woodland – Generalists 7.20.1 Abundance Trends Period England Trend SRSS Trend WRSS Trend 1977-2015 67% Weak increase 138% Weak increase 1993-2015 33% Weak increase -11% No change 34% Weak increase 42

Bird Trends in the Heart of England, 1977-2016 Long-tailed Tit abundance has increased over the long term, both nationally and locally. The SRSS is not correlated with the English trend, the WRSS is weakly correlated. The lack of correlation is due to short term population fluctuations, shown in the abundance chart, which could be due to their susceptibility to harsh winters. However, the overall trends are similar. 7.20.2 Abundance Chart

Long-tailed Tit Abundance 1977-2015 UKBI WRSS SRSS UKBI Trend WRSS Trend SRSS Trend 220 200 180 160 140 120 100 80

Index (100 in 1993) in (100 Index 60 40 20 0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

Long-tailed Tit abundance has increased over the long term but has now stabilised, both nationally and locally. 7.20.3 Distribution Chart

Long-tailed Tit Distribution 1977-2015 SRSS WRSS SRSS Trend WRSS Trend 80

20 % of 1km Survey Squares Survey 1km of % 10

0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The distribution chart shows that the population has spread in line with the increase in abundance for both of the surveys, becoming a very widespread species in the region.

Bird Trends in the Heart of England, 1977-2016 7.21 CHIFFCHAFF Phylloscopus collybita Numerous summer visitor with a few birds over-wintering UKBI Category: Woodland – Specialists 7.21.1 Abundance Trends Period England Trend SRSS Trend 1977-2015 251% Strong increase 1993-2015 161% Strong increase 32% Weak increase The SRSS is correlated with the English trend, showing a continuous increase, albeit at a slower rate. 7.21.2 Abundance Chart

Chiffchaff Abundance 1977-2015 UKBI SRSS UKBI Trend SRSS Trend 300

250

200

150

100 Index (100 in 1993) in (100 Index 50

0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The abundance chart shows that chiffchaff populations have been increasing locally and nationally at a similar rate. 7.21.3 Distribution Chart

Chiffchaff Distribution 1993-2015 SRSS SRSS Trend 90 85 80 75 70 65 60

55 % of 1km Survey Squares Survey 1km of % 50

The distribution chart shows that chiffchaffs now breed in over 90% of the BOS survey squares, up from 55%.

Bird Trends in the Heart of England, 1977-2016 7.22 WILLOW WARBLER Phylloscopus trochilus Numerous summer visitor; Amber UKBI Category: Woodland – Specialists 7.22.1 Abundance Trends Period England Trend SRSS Trend 1977-2015 -64% Weak decline 1993-2015 -33% Weak decline -81% Strong decline Willow Warblers are declining in England and this is matched in the BOS, with a strong correlation of the SRSS to the English index, with an even greater rate of decline locally. 7.22.2 Abundance Chart

Willow Warbler Abundance 1977-2015 UKBI SRSS UKBI Trend SRSS Trend 220 200 180 160 140 120 100 80

Index (100 in 1993) in (100 Index 60 40 20 0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015 The abundance chart shows an almost continuous decline within England and BOS. Aplin (Aplin, 1889) stated that Willow Warbler was the most abundant and distributed of the warblers, more so than Chiffchaff, a situation that has now reversed. 7.22.3 Distribution Chart

Willow Warbler Distribution 1993-2015 SRSS SRSS Trend 70

% of 1km Survey Squares Survey 1km of % 10

The distribution chart shows that Willow Warblers were widely distributed within the BOS but have rapidly become a more localised species.

Bird Trends in the Heart of England, 1977-2016 7.23 BLACKCAP Sylvia atricapilla Numerous summer visitor with some birds over-wintering UKBI Category: Woodland – Specialists 7.23.1 Abundance Trends Period England Trend SRSS Trend 1977-2015 244% Strong increase 1993-2015 130% Strong increase 52% Weak increase The SRSS is strongly correlated with the English trend, with a similar pattern of increase but at a lower rate. 7.23.2 Abundance Chart

Blackcap Abundance 1977-2015 UKBI SRSS UKBI Trend SRSS Trend 250

200

150

100 Index (100 in 1993) in (100 Index 50

0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The abundance chart shows a steady increase in the Blackcap population at both national and local level. 7.23.3 Distribution Chart Blackcap Distribution 1993-2015 SRSS SRSS Trend 100

60 % of 1km Survey Squares Survey 1km of %

The distribution chart shows that Blackcaps now breed in most of the BOS area.

Bird Trends in the Heart of England, 1977-2016 7.24 GARDEN WARBLER Sylvia borin Numerous summer visitor UKBI Category: Woodland – Specialists 7.24.1 Abundance Trends Period England Trend SRSS Trend 1977-2015 7% No change 1993-2015 -21% No change -71% Strong decline The SRSS is weakly correlated with the English trend, with a much higher rate of decline. 7.24.2 Abundance Chart

Garden Warbler Abundance 1977-2015 UKBI SRSS UKBI Trend SRSS Trend 140

120

100

40 Index (100 in 1993) in (100 Index 20

0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The abundance chart shows a significant decline in the breeding population within the BOS, far greater than the national trend where there are signs that the decline is slowing. 7.24.3 Distribution Chart

Garden Warbler Distribution 1993-2015 SRSS SRSS Trend 50

10 % of 1km Survey Squares Survey 1km of % 0

The distribution chart shows that garden warblers are a widespread breeder in the BOS, with the rate of distribution decline not as great as the total population decline.

Bird Trends in the Heart of England, 1977-2016 7.25 LESSER WHITETHROAT Sylvia curruca Fairly numerous summer visitor UKBI Category: Woodland – Generalists 7.25.1 Abundance Trends Period England Trend SRSS Trend 1977-2015 -3% No change 1993-2015 18% No change -14% No change There has been no significant change in populations nationally or locally in the survey period. 7.25.2 Abundance Chart

Lesser Whitethroat Abundance 1977-2015 UKBI SRSS UKBI Trend SRSS Trend 160

140

120

100

80 Index (100 in 1993) in (100 Index 60

40 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The abundance chart shows a small variation in populations with a possible slow long-term decline. 7.25.3 Distribution Chart Lesser Whitethroat Distribution 1993-2015 SRSS 40

0 % of 1km Survey Squares Survey 1km of %

The distribution chart shows that Lesser Whitethroat distribution has not changed, being present in around 30% of the region. The ABSS of 1984 and 2010 (Brownett A. , Lesser Whitethroat Survey 2010) found a small decline in the breeding population. The ABSS surveys indicated there was a preference for hedgerows, especially those associated with permanent pasture as opposed to arable fields.

Bird Trends in the Heart of England, 1977-2016 7.26 WHITETHROAT Sylvia communis Numerous summer visitor UKBI Category: Farmland – Specialists 7.26.1 Abundance Trends Period England Trend SRSS Trend 1977-2015 27% No change 1993-2015 48% Weak increase 23% No change The SRSS is weakly correlated with the English trend, showing a similar population increase. The population was impacted by severe droughts in the Sahel region of Africa in the 1960s, so the population could still be increasing from those lows (Easterbrook, 2013). 7.26.2 Abundance Chart

Whitethroat Abundance 1977-2015 UKBI SRSS UKBI Trend 200 180 160 140 120 100

Index (100 in 1993) in (100 Index 80 60 40 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The abundance chart shows the gradual increase in the national population and possibly locally, though it is not possible to fit a trend with statistical confidence. 7.26.3 Distribution Chart

Whitethroat Distribution 1993-2015 SRSS 85 80 75 70 65 60 55

50 % of 1km Survey Squares Survey 1km of %

Whitethroats are widely distributed across the BOS with no significant change.

Bird Trends in the Heart of England, 1977-2016 7.27 NUTHATCH Sitta europaea Fairly numerous resident UKBI Category: Woodland – Specialists 7.27.1 Abundance Trends Period England Trend SRSS Trend WRSS Trend 1977-2015 168% Strong increase 519% Strong increase 1993-2015 122% Strong increase 120% Strong increase 275% Strong increase Nuthatch populations have increased significantly, both nationally and locally. The SRSS and WRSS indices are strongly correlated with the English trend. 7.27.2 Abundance Chart Nuthatch Abundance 1977-2015 UKBI WRSS SRSS UKBI Trend WRSS Trend SRSS Trend 500 450 400 350 300 250 200

150 Index (100 in 1993) in (100 Index 100 50 0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The abundance chart clearly indicates an almost continuous increase in populations, both nationally and locally at a similar rate. The ABSS in 1966 and 1992 (Brownett A. , Nuthatch Survey 1992) did not detect any significant change, which is similar to the national trend over the same period. The SRSS indicates that the population started to increase from 2004. The ABSS surveys detected a significant association with an area of woodland of 2 ha or more. 7.27.3 Distribution Chart Nuthatch Distribution 1977-2015 SRSS WRSS SRSS Trend WRSS Trend 35

% of 1km Survey Squares Survey 1km of % 5

0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015 The distribution chart shows how rare Nuthatches were in the 1970s (5% of the survey squares) compared to the present (20%-30%), with a steady increase. 50

Bird Trends in the Heart of England, 1977-2016 7.28 TREECREEPER Certhia familiaris Fairly numerous resident UKBI Category: Woodland – Specialists 7.28.1 Abundance Trends Period England Trend SRSS Trend WRSS Trend 1977-2015 -24% No change -24% No change 1993-2015 7% No change -58% Strong decline -32% Weak decline Nationally, Treecreepers have experienced a small decline. Locally there appears to be a more significant decline, though the BOS surveys show a significant fluctuation in populations. The local trend is different to the national index, with no correlation. This local difference might be due to sampling errors since they are a secretive species (Easterbrook, 2013). 7.28.2 Abundance Chart

Treecreeper Abundance 1977-2015 UKBI WRSS SRSS UKBI Trend WRSS Trend SRSS Trend 240 220 200 180 160 140 120 100 80 Index (100 in 1993) in (100 Index 60 40 20 0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The abundance chart shows that nationally the abundance has not changed significantly, but locally there was a decline during the 90s followed by a period of increase, though not to former levels. 7.28.3 Distribution Chart

Treecreeper Distribution 1977-2015 SRSS WRSS WRSS Trend 50

10 % of 1km Survey Squares Survey 1km of % 0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015 The WRSS shows a gradual decline in distribution, but this is not reflected in the SRSS. 51

Bird Trends in the Heart of England, 1977-2016 7.29 WREN Troglodytes troglodytes Abundant resident with extensive distribution UKBI Category: Woodland – Generalists 7.29.1 Abundance Trends Period England Trend SRSS Trend WRSS Trend 1977-2015 36% No change -27% No change 1993-2015 17% No change -28% Weak decline -8% No change In England Wrens have become slightly more abundant. This change is not shown in the BOS surveys. This may be because this species can be harder to locate and is affected by adverse weather, so some degree of variation is to be expected. 7.29.2 Abundance Chart

Wren Abundance 1977-2015 UKBI WRSS SRSS UKBI Trend WRSS Trend SRSS Trend 140 130 120 110 100 90 80 70

Index (100 in 1993) in (100 Index 60 50 40 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The abundance chart shows that Wren populations fluctuate, often due to weather conditions. 7.29.3 Distribution The Wren is widely distributed across the BOS, occurring in 90-100% of survey squares during the breeding season. 7.30 STARLING Sturnus vulgaris Numerous resident and very frequent winter visitor with extensive distribution; Red UKBI Category: Farmland – Specialists 7.30.1 Abundance Trends Period England Trend SRSS Trend WRSS Trend 1977-2015 -87% Strong decline -76% Weak decline 1993-2015 -70% Strong decline -61% Strong decline -49% Strong decline The SRSS and WRSS are strongly correlated with the English trend of a declining population.

Bird Trends in the Heart of England, 1977-2016 7.30.2 Abundance Chart

Starling Abundance 1977-2015 UKBI WRSS SRSS UKBI Trend WRSS Trend SRSS Trend 250

200

150

100 Index (100 in 1993) in (100 Index

0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The trends show a strong decline until the early 90s and then a slight decrease in the rate of decline, both locally and nationally. 7.30.3 Distribution Chart

Starling Distribution 1977-2015 SRSS WRSS SRSS Trend WRSS Trend 100

% of 1km Survey Squares Survey % 1km of 40

30 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The SRSS indicates that the breeding distribution of Starlings is decreasing across the region. 7.31 BLACKBIRD Turdus merula Abundant resident with continental influx during the winter UKBI Category: Woodland – Generalists 7.31.1 Abundance Trends Period England Trend SRSS Trend WRSS Trend 1977-2015 -10% No change -16% 1993-2015 14% No change -30% Weak decline 18% No change

Bird Trends in the Heart of England, 1977-2016 The SRSS and WRSS do not correlate with the English trend, with the local population fluctuation not recorded nationally. 7.31.2 Abundance Chart

Blackbird Abundance 1977-2015 UKBI WRSS SRSS UKBI Trend WRSS Trend SRSS Trend

160

140

120

100 Index (100 in 1993) in (100 Index

60 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The abundance chart shows that there has been some fluctuation in the local population levels but with no significant indicator of an increase or decline. Blackbird populations are supplemented by an influx of continental birds during the winter, so the WRSS trend needs to be treated with caution. 7.31.3 Distribution Blackbirds are amongst the most widely distributed species in the BOS, being observed in practically all 1km squares. 7.32 SONG THRUSH Turdus philomelos Numerous resident; Red UKBI Category: Woodland – Generalists 7.32.1 Abundance Trends Period England Trend SRSS Trend WRSS Trend 1977-2015 -35% No change -73% Weak decline 1993-2015 24% No change -10% No change 0% No change Song Thrush have undergone a slow decline nationally, though since the 1990s populations appear to have stabilised. This decline is mirrored in the BOS SRSS but not by the WRRS. The WRSS trend however is correlated with the England index, both showing a decline followed by an increase.

Bird Trends in the Heart of England, 1977-2016 7.32.2 Abundance Chart

Song Thrush Abundance 1977-2015 UKBI WRSS SRSS UKBI Trend WRSS Trend SRSS Trend 400

350

300

250

200

150 Index (100 in 1993) in (100 Index 100

0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The abundance chart shows that overall, the national and local population rates of change are broadly similar, though there was a more dramatic decline locally in the early 1970s. 7.32.3 Distribution Chart Song Thrush Distribution 1977-2015 SRSS WRSS SRSS Trend WRSS Trend 100

% of 1km Survey Squares Survey 1km of % 40

30 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The SRSS shows that Song Thrush are very widely distributed in the BOS, occupying 90-100% of survey squares. The WRSS shows a lower distribution of 50-60%. 7.33 SPOTTED FLYCATCHER Muscicapa striata Not Scarce summer visitor with local distribution; Red UKBI Category: Woodland – Specialists 7.33.1 Abundance Trends Period England Trend SRSS Trend 1977-2015 -89% Strong Decline 1993-2015 -53% Strong Decline -75% Strong Decline Spotted Flycatchers have declined significantly over both periods, nationally and locally. The SRSS index is correlated with the English trend. 55

Bird Trends in the Heart of England, 1977-2016 7.33.2 Abundance Chart Spotted Flycatcher Abundance 1977-2015 UKBI SRSS UKBI Trend SRSS Trend 500 450 400 350 300 250 200 150

Index (100 in 1993) in (100 Index 100 50 0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015 The abundance chart shows the continuous decline in Spotted Flycatchers, though locally the population has stabilised since 2005 as shown in the chart below which focuses on the period 1993-2015.

Spotted Flycatcher Abundance 1993-2015 UKBI SRSS UKBI Trend SRSS Trend 140

120

100

Index (100 in 1993) in (100 Index 20

7.33.3 Distribution Chart Spotted Flycatcher Distribution 1993-2015 SRSS SRSS Trend 40 35 30 25 20 15 10 5

% of 1km Survey Squares Survey 1km of % 0

Spotted Flycatchers were common in the BOS but their distribution has declined significantly, though there is an indication that this has improved since 2011. They can often be overlooked in casual observation so it is possible that they are more widespread and abundant than the BOS monthly sightings suggest. 56

Bird Trends in the Heart of England, 1977-2016 7.34 ROBIN Erithacus rubecula Abundant resident with extensive distribution UKBI Category: Woodland – Generalists 7.34.1 Abundance Trends Period England Trend SRSS Trend WRSS Trend 1977-2015 59% Weak increase 8% No change 1993-2015 36% Weak increase 3% No change 33% Weak increase Robins have become more abundant nationally, which is reflected in the BOS winter survey but not the BOS summer breeding survey. Neither of the BOS indices correlate with the national index. 7.34.2 Abundance Chart Robin Abundance 1977-2015 UKBI WRSS SRSS UKBI Trend WRSS Trend 170 160 150 140 130 120 110 100 90

Index (100 in 1993) in (100 Index 80 70 60 50 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015 The abundance chart shows the national increase, which is mirrored by the WRSS in recent years, but not by the SRSS. 7.34.3 Distribution Robins are very widely distributed across the BOS, occurring in up to 100% of survey squares. 7.35 DUNNOCK Prunella modularis Abundant resident; Amber UKBI Category: Woodland – Generalists 7.35.1 Abundance Trends Period England Trend SRSS Trend WRSS Trend 1977-2015 -27% No change -27% Weak decline 1993-2015 22% No change -15% No change 22% No change The SRSS is not correlated with the English trend, the WRSS is weakly correlated (see abundance chart).

Bird Trends in the Heart of England, 1977-2016 7.35.2 Abundance Chart

Dunnock Abundance 1977-2015 UKBI WRSS SRSS UKBI Trend WRSS Trend SRSS Trend

180

160

140

120

Index (100 in 1993) in (100 Index 100

60 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The abundance chart shows a national and local decline in the late 70s & 80s, followed by a small recovery. The recent local breeding decline needs to be monitored more closely to determine if the trend is significant. 7.35.3 Distribution Dunnocks are widely distributed across the BOS, breeding in over 90% of the area. 7.36 TREE SPARROW Passer montanus Not Scarce resident; Red UKBI Category: Farmland – Specialists 7.36.1 Abundance Trends In England, Tree sparrows suffered one of the sharpest declines in the 70s & 80s but have since increased from their low point.

Period England Trend SRSS Trend WRSS Trend 1977-2015 -95% Strong decline -99% Strong decline 1993-2015 101% Strong increase -67% Strong decline -97% Strong decline The SRSS is not correlated with the English index, showing a decline rather than an increase. The WRSS is strongly correlated with the English trend over the long-term. Tree Sparrows in the BOS are still declining, unlike the English situation. The increases seen in England have occurred in the north (Massimino, et al., 2017), whilst in the south the population is too small to feature in the BTO BBS regional indexes. Directly to the south of the BOS, Tree Sparrows have become extremely localised (Berkshire Ornithological Club, 2015). Within the BOS, the small population that remains is now confined to the northern part of the study area. Various conservation projects in the Wiltshire area have produced encouraging results in increasing local populations (Tree Sparrow Villages, 2018).

Bird Trends in the Heart of England, 1977-2016 7.36.2 Abundance Chart Tree Sparrow Abundance 1977-2015 UKBI WRSS SRSS UKBI Trend WRSS Trend 4000 3500 3000 2500 2000 1500

Index (100 in 1993) in (100 Index 1000 500 0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The major decline in the 70s& 80s makes it difficult to see the current situation, so the chart below focuses on the medium term. This shows the population increase in England and the continued decline in the BOS. Tree Sparrow Abundance 1993-2015 UKBI WRSS SRSS UKBI Trend WRSS Trend SRSS Trend 250

200

150

100

Index (100 in 1993) in (100 Index 50

7.36.3 Distribution Chart Tree Sparrow Distribution 1977-2015 SRSS WRSS SRSS Trend WRSS Trend 50

% of 1km Survey Squares Survey 1km of % 0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

Bird Trends in the Heart of England, 1977-2016 The chart above shows that Tree Sparrows are becoming a very localised species, having once been widespread in the region. This is also shown by the BOS monthly records, which record all sightings since the late 80s. These show a distribution decline from 20% to 10% of the region.

Tree Sparrow BOS Sightings Distribution 300

250

200

150

100 No. of 1km 1km ofSquares No. 50

0 1982-86 1987-91 1992-96 1997-01 2002-06 2007-11 2012-16

The Thames and Chiltern Bird Atlas (Thames and Chiltern Bird Atlas Group, 2016) shows that Tree Sparrows have a significantly reduced breeding range. In the 1980-92 atlas, breeding was widespread, but the 2007-12 atlas shows a limited breeding range of North Oxfordshire and Hertfordshire and very limited in the south.

Thames & Chiltern Bird Atlas – Tree Sparrow Distribution Change

Bird Trends in the Heart of England, 1977-2016 7.37 CHAFFINCH Fringilla coelebs Abundant resident with widespread distribution UKBI Category: Woodland – Generalists 7.37.1 Abundance Trends Period England Trend SRSS Trend WRSS Trend 1977-2015 10% No change -36% 1993-2015 -2% No change -30% Weak decline -46% Strong decline Neither the SRSS or WRSS indices are correlated with the English trend, showing a localised population decline. 7.37.2 Abundance Chart Chaffinch Abundance 1977-2015 UKBI WRSS SRSS UKBI Trend WRSS Trend SRSS Trend 130

120

110

100

Index (100 in 1993) in (100 Index 70

50 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The abundance chart shows a localised decline in Chaffinch populations, though there is an indication of short-term decline at the national level too. 7.37.3 Distribution Despite the local reduction in abundance, Chaffinches are still widely distributed across the BOS, being recorded in most 1km2 squares. 7.38 GREENFINCH Chloris chloris Numerous resident with widespread distribution UKBI Category: Farmland – Generalists

7.38.1 Abundance Trends Period England Trend SRSS Trend WRSS Trend 1977-2015 -41% Weak decline -29% No change 1993-2015 -40% Weak decline -46% Weak decline -41% Weak decline The SRSS is strongly correlated to the English trend, the WRSS is weakly correlated, showing the recent sharp decline in populations after the increase to 2006.

Bird Trends in the Heart of England, 1977-2016 7.38.2 Abundance Chart

Greenfinch Abundance 1977-2015 UKBI WRSS SRSS UKBI Trend SRSS Trend 200

180

160

140

120

100

Index (100 in 1993) in (100 Index 60

0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

Greenfinch populations were slowly increasing until the mid-2000s, since when they have declined rapidly. It is known that Greenfinches are particularly affected by Trichomonosis, this being noted by the BTO as occurring in late summer 2006 (BTO Garden Bird Watch, 2018), so there appears to be a direct correlation with the recent population decline and the outbreak of this disease. 7.38.3 Distribution Chart Greenfinch Distribution 1977-2015 SRSS WRSS WRSS Trend 100

60 % of 1km Survey Squares Survey 1km of % 50

40 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The WRSS shows a distribution decline from 2007, matching the abundance decline. The breeding survey does not show a decline until a few years later, indicating that densities fell before overall distribution declined.

Bird Trends in the Heart of England, 1977-2016 7.39 GOLDFINCH Carduelis carduelis Numerous resident with extensive distribution UKBI Category: Farmland – Specialists 7.39.1 Abundance Trends Period England Trend SRSS Trend WRSS Trend 1977-2015 25% No change 212% Strong increase 1993-2015 147% Strong increase 176% Strong increase 192% Strong increase Goldfinches have increased significantly nationally and locally. The SRSS and WRSS are strongly correlated to the English trend. 7.39.2 Abundance Chart

Goldfinch Abundance 1977-2015 UKBI WRSS SRSS UKBI Trend WRSS Trend SRSS Trend 350

300

250

200

150

Index (100 in 1993) in (100 Index 100

0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015 The abundance chart shows a significant decline to the late 1980s followed by an increase to above former levels in recent years. The BOS trend closely follows the English trend.

7.39.3 Distribution Chart Goldfinch Distribution 1977-2015 SRSS WRSS SRSS Trend WRSS Trend 100 90 80 70 60 50 40 30

% of 1km Survey Squares Survey 1km of % 20 10 0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015 Goldfinches have increased to become a very widely distributed species across the BOS. 63

Bird Trends in the Heart of England, 1977-2016 7.40 LINNET Linaria cannabina Numerous resident with extensive distribution; Red UKBI Category: Farmland – Specialists 7.40.1 Abundance Trends Period England Trend SRSS Trend WRSS Trend 1977-2015 -56% Weak decline -44% Weak decline 1993-2015 2% No change -61% Strong decline -3% No change The SRSS is weakly correlated to the English trend, the WRSS is not correlated. The trends indicate that Linnets are declining faster in the BOS than nationally. 7.40.2 Abundance Chart

Linnet Abundance 1977-2015 UKBI WRSS SRSS UKBI Trend WRSS Trend SRSS Trend

200

150

100

Index (100 in 1993) in (100 Index 50

0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

Nationally, Linnets declined in the 1970s but have since stabilised, a trend the WRSS broadly shows. The SRSS indicates that the breeding population is undergoing a significant local decline. 7.40.3 Distribution Charts Linnet Distribution 1977-2015 SRSS WRSS SRSS Trend 80

20 % of 1km Survey Squares Survey 1km of % 10

0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The SRSS shows that Linnet distribution has slowly shrunk to about 50% of the region, but this change is not evident from the WRSS where little change has been detected.

Bird Trends in the Heart of England, 1977-2016

Linnet BOS Sightings Distribution 160 140 120 100 80 60

40 No. of 1km 1km ofSquares No. 20 0 1982-86 1987-91 1992-96 1997-01 2002-06 2007-11 2012-16

The monthly sightings indicate that distribution has remained stable at around 12% of the BOS, which directly compares with the WRSS index value. Note that monthly recording was for flocks over 50, but this has been reduced to 20 or more in recent years.

7.41 BULLFINCH Pyrrhula pyrrhula Fairly numerous resident; Amber UKBI Category: Woodland – Generalists 7.41.1 Abundance Trends Period England Trend SRSS Trend WRSS Trend 1977-2015 -50% Weak decline -65% Weak decline 1993-2015 9% No change 1% No change -27% Weak decline Bullfinches have declined nationally over the long term, with the population level stabilising in the short term. This pattern is reflected in the WRSS which is strongly correlated, but not in the SRSS, though the overall pattern is similar. 7.41.2 Abundance Chart

Bullfinch Abundance 1977-2015 UKBI WRSS SRSS UKBI Trend WRSS Trend SRSS Trend 220

200

180

160

140

120

Index (100 in 1993) in (100 Index 100

40 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

Bird Trends in the Heart of England, 1977-2016 The abundance chart shows a noticeable decline in both local and national populations in the late 70s & early 80s, with a subsequent stabilisation. 7.41.3 Distribution Chart

Bullfinch Distribution 1977-2015 SRSS WRSS WRSS Trend 80

% of 1km Survey Squares Survey 1km of % 40

30 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The distribution chart shows that Bullfinches are a widespread breeder within the BOS, with no notable change in breeding distribution. The WRSS indicates that the distribution is declining. 7.42 YELLOWHAMMER Emberiza Citronella Numerous resident; Red UKBI Category: Farmland – Specialists 7.42.1 Abundance Trends Period England Trend SRSS Trend WRSS Trend 1977-2015 -59% Weak decline -76% Weak decline 1993-2015 -37% Weak decline -23% No change -68% Strong decline The SRSS is weakly correlated with the English trend, the WRSS is strongly correlated. This indicates that Yellowhammers are declining in line with the national trend.

Bird Trends in the Heart of England, 1977-2016 7.42.2 Abundance Chart Yellowhammer Abundance 1977-2015 UKBI WRSS SRSS UKBI Trend WRSS Trend SRSS Trend 200 180 160 140 120 100

80 Index (100 in 1993) in (100 Index 60 40 20 0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

Yellowhammer populations have almost continuously declined over the survey period, both nationally and locally, with the local decline increasing in recent years. It is possible that some of the recent decline was due to the harsh winters of 2009-11. 7.42.3 Distribution Chart

Yellowhammer Distribution 1977-2015 SRSS WRSS SRSS Trend WRSS Trend

100

60 % of 1km Survey Squares Survey 1km of % 50

40 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

Yellowhammers are widely distributed across the BOS, but the trends suggest that there is a decline in distribution. 7.43 REED BUNTING Emberiza schoeniclus Fairly numerous resident; Amber UKBI Category: Farmland – Generalists 7.43.1 Abundance Trends Period England Trend SRSS Trend WRSS Trend 1977-2015 -31% No change -83% Strong decline 1993-2015 26% No change 94% Strong increase -11% No change Neither the SRSS or WRSS are correlated with the English trend, though the overall population trend from 1993-2015 appears similar, i.e. no significant change. 67

Bird Trends in the Heart of England, 1977-2016 7.43.2 Abundance Chart

Reed Bunting Abundance 1977-2015 UKBI WRSS SRSS UKBI Trend SRSS Trend 500

400

300

200 Index (100 in 1993) in (100 Index 100

0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

The chart shows that the English population has remained relatively unchanged since 1993, but locally there appears to be a significant increase in recent years. The significant variations shown in the WRSS are unexplained, though it is known via ringing studies that the resident population is supplemented by visitors from outside of the area (Easterbrook, 2013). 7.43.3 Distribution Charts

Reed Bunting Distribution 1977-2015 SRSS WRSS WRSS Trend 35

10 % of 1km Survey Squares Survey 1km of % 5

0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015 There is considerable variation in the SRSS index, less so in the WRSS, but the overall situation appears to show a stable distribution. This is backed up from the monthly sightings, shown below. Note that monthly sightings are only requested for flocks of 10 or more, so do not show all potential occurrences.

Bird Trends in the Heart of England, 1977-2016

Reed Bunting BOS Sightings Distribution 250

200

150

100

No. of 1km Squares 1km of No. 50

0 1982-86 1987-91 1992-96 1997-01 2002-06 2007-11 2012-16

7.44 CORN BUNTING Emberiza calandra Not Scarce resident; Red UKBI Category: Farmland – Specialists 7.44.1 Abundance Trends Period England Trend SRSS Trend WRSS Trend 1977-2015 -86% Strong decline -99% Strong decline 1993-2015 -38% Weak decline -96% Strong decline -98% Strong decline Corn Buntings have declined significantly nationally and locally. The SRSS is weakly correlated to the English trend, probably due to the greater rate of local decline. The WRSS is strongly correlated. 7.44.2 Abundance Chart

Corn Bunting Abundance 1977-2015 UKBI WRSS SRSS UKBI Trend WRSS Trend SRSS Trend 500 450 400 350 300 250 200 Index (100 in 1993) in (100 Index 150 100 50 0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

Corn Buntings declined very rapidly in the 1970s & 80s, with a slower rate since then. The chart below focuses on the short-term period 1993-2015 to show that locally Corn Buntings have continued to decline whereas nationally populations have stabilised.

Bird Trends in the Heart of England, 1977-2016

Corn Bunting Abundance 1993-2015 UKBI WRSS SRSS UKBI Trend WRSS Trend SRSS Trend 200 180 160 140 120 100 80 60

Index (100 in 1993) in (100 Index 40 20 0

7.44.3 Distribution Charts Corn Bunting Distribution 1977-2015 SRSS WRSS SRSS Trend WRSS Trend 20

% of 1km Survey Squares Survey 1km of % 0 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015

A BOS survey in 1957 showed Corn Bunting to be well distributed with significant numbers in the south of the area. The SRSS surveys show that breeding has reduced to just a few small, isolated pockets (Easterbrook, 2013).

Corn Bunting BOS Sightings Distribution 180 160 140 120 100 80 60

40 No. of 1km 1km ofSquares No. 20 0 1982-86 1987-91 1992-96 1997-01 2002-06 2007-11 2012-16

Note: Corn Bunting records were only fully submitted from 1992 onwards. The Thames and Chiltern Bird Atlas (Thames and Chiltern Bird Atlas Group, 2016) shows that Corn Buntings have reduced their breeding range. In the 1980-92 atlas breeding was widespread, but the 2007-12 atlas shows a limited 70

Bird Trends in the Heart of England, 1977-2016 breeding range in Oxfordshire with a concentration in the south of the county, spreading into north Berkshire and then NE into Bucks and Herts. In 2016 BOS carried out a Corn Bunting Survey to assess the current distribution and populations. Squares were surveyed in areas where Corn Bunting were known to be present from previous years. The 2016 survey results detected breeding at only three sites, with only one site in the SE of the BOS area containing a significant number (Curnow, 2016). In former breeding sites in the west of the area extending NE along high ground, only one breeding site was detected.

Thames & Chiltern Bird Atlas – Corn Bunting Distribution Change

Bird Trends in the Heart of England, 1977-2016

7.45 Species Summary The summary table lists the species that are showing a strong or weak decline in the BOS in the period 1993-2015 as assessed either by the breeding survey (SRSS) or the winter survey (WRSS). The percentages are expressed as the rate of population change over a nominal 25-year period rather than the amount over the period 1977-2015 or 1993-2015. This is done to allow the rate of change to be compared between the two different survey periods. The percentages in the table below are therefore different from those in the individual species accounts. See section 5.2 for a definition of “Strong” and “Weak” decline or increase.

SRSS WRSS England England WRSS England 1993- SRSS Medium 1993- WRSS Medium 1993- Medium Term 1977- WRSS Long 1977- England Long Species 2015 Term Trend 2015 Term Trend 2015 Trend 2015 Term Trend 2015 Term Trend

Corn Bunting -104% Strong Decline -106% Strong Decline -44% Weak Decline -63% Strong Decline -56% Strong Decline

Willow Warbler -88% Strong Decline -36% Weak Decline -41% Weak Decline Sparrowhawk -83% Strong Decline -10% No Change -19% No Change 315% Strong Increase 37% Weak Increase

Spotted Flycatcher -82% Strong Decline -58% Strong Decline -57% Strong Decline Garden Warbler -77% Strong Decline -23% No Change 4% No Change Tree Sparrow -73% Strong Decline -105% Strong Decline 51% Weak Increase -63% Strong Decline -61% Strong Decline

Starling -66% Strong Decline -53% Strong Decline -73% Strong Decline -49% Weak Decline -55% Strong Decline

Linnet -66% Strong Decline -4% No Change -17% No Change -28% Weak Decline -37% Weak Decline

Treecreeper -63% Strong Decline -34% Weak Decline 7% No Change -15% No Change -16% No Change

Greenfinch -50% Weak Decline -45% Weak Decline -43% Weak Decline -19% No Change -28% Weak Decline

Rook -46% Weak Decline -34% Weak Decline 12% No Change -17% No Change 9% No Change

Marsh Tit -46% Weak Decline 17% No Change -47% Weak Decline 16% No Change -38% Weak Decline

Coal Tit -46% Weak Decline 20% No Change 26% No Change 72% Weak Increase 3% No Change

Skylark -38% Weak Decline -64% Strong Decline -28% Weak Decline -54% Strong Decline -41% Weak Decline

Chaffinch -33% Weak Decline -50% Strong Decline -3% No Change -23% No Change 7% No Change

Blackbird -33% Weak Decline 20% No Change 15% No Change -10% No Change -6% No Change

Bird Trends in the Heart of England, 1977-2016

Wren -30% Weak Decline -8% No Change 19% No Change -17% No Change 23% No Change

Willow Tit -102% Strong Decline -80% Strong Decline -63% Strong Decline -58% Strong Decline Lapwing -100% Strong Decline -16% No Change -62% Strong Decline -38% Weak Decline Grey Partridge -47% Weak Decline -61% Strong Decline -51% Strong Decline -59% Strong Decline

The following table lists the species with a strong or weak increase in the BOS in the period 1993-2015 as assessed by the breeding survey (SRSS).

Goldfinch 191% Strong Increase 208% Strong Increase 144% Strong Increase 136% Strong Increase 36% Weak Increase

Nuthatch 130% Strong Increase 299% Strong Increase 132% Strong Increase 333% Strong Increase 108% Strong Increase

Great Spotted Woodpecker 121% Strong Increase 221% Strong Increase 138% Strong Increase 64% Weak Increase 75% Weak Increase

Jackdaw 112% Strong Increase 60% Weak Increase 92% Weak Increase 238% Strong Increase 89% Weak Increase

Reed Bunting 102% Strong Increase -11% No Change 26% No Change -53% Strong Decline -20% No Change

Kestrel 93% Weak Increase 102% Strong Increase -23% No Change 126% Strong Increase -27% Weak Decline

Jay 93% Weak Increase -2% No Change 8% No Change 13% No Change -6% No Change

Green Woodpecker 57% Weak Increase 92% Weak Increase 66% Weak Increase 35% Weak Increase 65% Weak Increase

Blackcap 57% Weak Increase 142% Strong Increase 156% Strong Increase

Bird Trends in the Heart of England, 1977-2016

8. Conclusion Prior to this report it was unknown if the status of species within the BOS was similar to (i.e. correlated with) or different from the national population trends. The analysis for this report has shown that there is a close correlation between the English and BOS Farmland bird species index. It was interesting to find that the BOS winter survey was also closely correlated, even though it is measuring winter populations, not breeding. This is probably a reflection of the species being resident with minimal seasonal population movements. The correlation also occurs when looking at Specialist farmland birds, but not for Generalists where there was a local population increase & then decline in the period 2003-2011. Specialist farmland birds are declining locally and nationally, with evidence of a higher rate of decline locally. Generalist farmland birds have not declined so much, locally or nationally. Nationally, 37% of the farmland birds have experienced a decline from 1993-2015 (Defra, 2017) and 47% within the BOS. The species of local concern are: Tree Sparrow, Lapwing, Greenfinch, Reed Bunting, Corn Bunting, Grey Partridge, Linnet, Skylark, Starling and Yellowhammer. The situation is significantly different for species in the woodland index, with the BOS showing a significant decline from 1994-2000, followed by a period of recovery to 2010 and then another ongoing decline. In comparison, the English trend shows a small decline over the entire period with no intermediate recovery. Nationally, 26% of the woodland birds have experienced a decline from 1993-2015 (Defra, 2017) compared with 38% within the BOS. The species of local concern are: Willow Warbler, Sparrowhawk, Spotted Flycatcher, Garden Warbler, Treecreeper, Marsh Tit and Willow Tit.

These findings will allow the BOS to target its future conservation efforts in the area by raising the profile of the affected species. This report will be shared with organisations that have an interest in and influence upon farmland and woodland bird conservation. We hope it can also be used to help promote awareness of the need for action for declining species and help prevent their extinction in our area.

This report illustrates the importance of local monitoring and surveys, especially over the long term. The findings help to corroborate the national analysis whilst also highlighting local differences. This is of special significance to local organisations implementing planning and conservation policies who would otherwise only have national information to guide them on their plans. Providing a localised analysis of species trends enables the fine tuning of policies to meet local requirements.

Bird Trends in the Heart of England, 1977-2016

9. Appendices 9.1 National Bird Trends Data The national reports provide summaries of bird trends from 1970 to 2015/6. The statistical data is published by Defra at https://www.gov.uk/government/collections/biodiversity-and-wildlife- statistics, with coverage for the UK and England. For this report, only the data for England is used. The Defra data is identified in this report as “UKBI” – the UK Bird Indicator dataset. The Defra data is based on the BTO bird indicator data collected via the Breeding Bird Survey (BBS), the Common Bird Census (CBC) and Wetland Bird Survey (WeBS). See the BTO website: Science > Monitoring > Bird Indicators: https://www.bto.org/science/monitoring/developing-bird-indicators. The indicators used are a measure of the breeding population abundance at the monitoring sites. Data for individual species are summarised into the following groups: • Farmland – 19 species, 7 generalist & 12 specialists • Woodland – 32 species, 12 generalist & 22 specialists • Water and Wetland – 26 species o 4 Reedbed o 8 Wet meadow o 4 Fast flowing water o 6 Slow and standing water o 4 others • Seabirds – 11 species, 5 surface feeders and 4 subsurface feeders • 31 other species used in the “All Birds” indicator • Wintering Water birds – 41 species, 22 wildfowl and 15 waders The term Generalists is used to denote species that primarily use the habitat specified but can also use other habitats. For example, Blackbirds are classified under woodland, but are also associated with farmland. Specialist species tend to only use the habitat specified, e.g. Corn Bunting. The list of species in each group is provided within the relevant section of this report. For this report, the comparison with national data primarily focuses on the farmland species since that is the dominant land use within the BOS – see breakdown below. Whilst woodland species do occur, the BOS surveys do not specifically target woodland areas, so comparison with the woodland index is more difficult. A BOS survey of land use in the BOS area conducted in the 2000s gave this breakdown: • 83.4% farmland • 7.5% woodland • 6.5% built-up • 0.3% water • 4.5% other The national Water and Wetland indicators utilise data for many species that do not breed within the BOS, so this category has been excluded.

Bird Trends in the Heart of England, 1977-2016

9.2 BTO Bird Trend Data The BTO bird trend data is used as the source for the Defra/JNCC UK Bird Indicators. The data comes from several long-term surveys: • Common Bird Census (CBC), 1962-2000: a survey of breeding birds in farmland and woodland • Breeding Bird Survey (BBS), 1994 onwards: uses a simpler survey technique than the CBC, allowing coverage to be extended to other habitats. The period 1994-2000 was used to enable calibration with the CBC, which it then superseded. • Waterways Bird Survey (WBS), 1974-2007: a survey of 24 water-birds on rivers • Waterways Breeding Bird Survey (WBBS), 1998 onwards: the successor to the WBS, with the period 1998-2007 being used to calibrate with the WBS. • Wetland Bird Survey (WeBS): monitors non-breeding water-birds. The data is used to supplement the WBBS/WBS trends. BTO combine the CBC & BBS and WBS & WBBS data into 2 long term indexes which cover the period 1966-2016. This data is used by Defra, JNCC and the RSPB for the production of the indexes and statistical information in their reports. For this report, just the CBC/BBS dataset is used. The CBC/BBS indices are published for the UK, national countries and for the main regions within England. Because the BOS overlaps 3 regions (East & West Midlands and South-East England), the CBC/BBS England indices are used. 9.3 BOS Bird Trends Data The BOS equivalent of the BTO CBC/BBS is the Summer Random Square Survey (SRSS), which has been conducted annually since 1991, recording the number of breeding pairs per 1km square. Unlike the BTO BBS which re-surveys sites each year, 1km squares are randomly selected and surveyed each year, with the aim to cover as much of the BOS region as possible. To date 30% of the BOS area has been surveyed, with 57 species having continuous (non-zero) records. The aim of the survey is to assess the breeding population of all species in each of the surveyed 1km squares. The BOS also conducts the Winter Random Square Survey (WRSS), which has been running since 1975. The survey is conducted in a similar way to the SRSS, selecting different 1km squares each year. When all accessible squares have been surveyed (which has occurred twice so far), the area is re-surveyed in a new random order. Two surveys are conducted per winter, one in late November and again at the end of February. 65 species have continuous records, i.e. they have been recorded each year. The survey records all species observed, noting total species counts and maximum flock sizes. In both the SRSS and WRSS the data are converted into two indices – one for abundance and the other for distribution. Each index is calibrated at 100 for each species at the survey period start. This makes it easy to determine if populations are increasing or decreasing by comparing the index value over time. Data from 3 years of surveys is combined to produce a moving average so as to reduce annual fluctuations. More information on the surveys can be found on the BOS website under Fieldwork: http://www.banburyornithologicalsociety.org.uk/index.php/fieldwork. To enable comparison between the BOS and UKBI indices, the BOS SRSS & WRSS abundance indexes for each species have been combined using the same statistical methods. This allows us to produce the BOS equivalent of the UKBI farmland and woodland indexes. Some species are absent in the BOS indices – this is detailed in the relevant sections.

Bird Trends in the Heart of England, 1977-2016

9.3.1 Distribution Charts To enable an insight into the distribution changes of each species within the BOS, a basic analysis of the occurrence of each species has been performed from each survey square. The SRSS samples approximately 1-2% of the BOS each year, the WRSS 4-5%, providing a reasonable sampling rate to estimate the total percentage distribution for each species for the whole of the BOS. This extrapolation is possible for the species concerned, since the land cover for the BOS is similar across the region, i.e. the habitat differences are not major. Because there is significant annual variation, the distribution charts present a trend line which smooths out the annual variation, providing a more accurate estimate of rate of distribution change. 9.4 Trends Analysis Statistical Techniques 9.4.1 Survey Data Processing The base data for this report has been statistically processed to enable the overall trends to be detected more clearly. Both the national and BOS datasets are derived from survey information that is subject to a significant amount of site and annual variation. The survey data is not just averaged, but subject to mathematical processing that attempts to reduce the impact of short-term variation (e.g. adverse weather) so that the longer-term trend can be detected. The national data, derived from the BTO BBS data, is smoothed using a complex model that is mathematically equivalent to a generalised additive model (BTO, 2017). The BOS data uses a 3-year moving average technique which is a common method for time-series trends analysis and is the approach the BOS has historically used to present its data. In both cases these techniques produce a single figure per year per species that can be plotted as a line on a chart. Statistically these are not a line, but a broad band with an upper and lower bound, known mathematically as the upper and lower confidence limits. The Defra Wild Bird Populations and BTO BBS Trends reports show these bounds as a shaded area around the plotted line. This technique has not been used in this report because the BOS and BTO data lines are plotted on a single chart and adding the lower/upper bounds for each line would detract from the presentation, making it difficult for readers to see the similarity or difference between the national and local trends, which is the main aim of this report. The smoothed data can be used to compare the changes in species populations between the BOS and England by calculating the amount of relative change in each dataset and by calculating the correlation coefficients between the two datasets. The correlation coefficients are used to determine if there is a statistically valid similarity in the population changes at the national and local level. In this report, rather than present the correlation coefficients numerically, the terms “strong”, “weak” and none are used, to simplify the presentation to make it more understandable to a wider audience. 9.4.2 Trend Lines In many of the line charts a trend line has been fitted, shown as a dotted line. The trend lines are presented to give an idea of the overall rate of trend, smoothing out the fluctuations that would otherwise be present. Trend lines have only been added where the degree of fit is good, as measured using the R2 Pearson coefficient. The coefficient is used to determine if a linear or curved line is the best fit. For linear trends, the least-squares method is used to calculate the trend line. Curved lines are calculated using a 2 or 3 order polynomial equation.

Bird Trends in the Heart of England, 1977-2016

9.5 BOS Survey Area Map The BOS survey area is defined as the 12 10km squares specified by the Ordnance Survey grid references SP32-35, SP42-45 & SP52-55. The dashed grey lines on the map show the county boundaries (Oxfordshire, Northamptonshire, Warwickshire).

BOS Survey Area

The BOS survey area in relation to England

Bird Trends in the Heart of England, 1977-2016

9.6 BOS Area Land Cover Map The following map shows the dominant land cover for each 1km2 square in the BOS. The data come from the Centre for Ecology & Hydrology Land Cover map 2015 (CEH: Rowland et al., 2017) which is derived from satellite mapping. The main water bodies and rivers have been added for reference.

9.7 Acknowledgements The long-term BOS monitoring schemes were devised and implemented by Trevor Easterbrook, BOS Bird Recorder 1975-2016. Without the huge contribution made by BOS bird survey volunteers over the past 40 years in carrying out the bird monitoring fieldwork this paper would not have been possible. This report makes extensive use of the BTO Breeding Bird Survey data (Harris, et al., 2017) which the BTO supplied to the BOS for this report. The Breeding Bird Survey is run by the British Trust for Ornithology (BTO) and is jointly funded by the BTO, the Joint Nature Conservation Committee (JNCC) (on behalf of the statutory nature conservation bodies: Department of Agriculture, Environment and Rural Affairs – Northern Ireland, Natural England, Natural Resources Wales and Scottish Natural Heritage), and the Royal Society for the Protection of Birds (RSPB). This report also makes use of the information provided in the JNCC/Defra publication “Wild Bird Populations in England, 1970 to 2016”, which in turn is based on the same BTO indices. The report has also benefitted from technical and editorial input from Mike Pollard, Frances Buckel, Helen Raine and Jonathan Bowley.

Bird Trends in the Heart of England, 1977-2016

9.8 Glossary of Terms

Term Description ABSS The BOS Annual Breeding Season Survey BBS BTO Breeding Bird Survey BoCC4 Birds of Conservation Concern 4 BOS Banbury Ornithological Society BTO British Trust for Ornithology CEH Centre for Ecology & Hydrology Correlation A statistical measure that indicates how closely two datasets are related. A strong correlation indicates that the values increase and decrease in a similar way. Defra Department for Environment, Food and Rural Affairs Index In this report Index is used to refer to a relative measure of bird populations over time. The index values are not comparable in terms of population sizes across different species or surveys, they are only a measure of the amount of change within the species and survey. JNCC Joint Nature Conservation Committee SRSS BOS Summer Random Square Survey, an annual survey of breeding birds within the BOS. UKBI UK Bird Indicator – an index of abundance derived from the BTO breeding surveys for a group of species. WRSS BOS Winter Random Square Survey, an annual survey of over-wintering species in the BOS.

10. References Aplin, O. V. (1889). The Birds of Oxfordshire. Berkshire Ornithological Club. (2015). County Atlas: Tree Sparrow. Retrieved from http://berksoc.org.uk/county-atlas/distribution-maps/tetrad- maps/?speciesname=Tree%20Sparrow Brownett, A. (1992). Nuthatch Survey 1992. BOS Annual Report 1992. Brownett, A. (2000). Great Spotted Woodpecker Survey 2000. BOS Annual Report 2000. Brownett, A. (2002). Green Woodpecker Survey 2002. BOS Annual Report 2002. Brownett, A. (2006). Lapwing Survey 2006. BOS Annual Report 2006. Brownett, A. (2006). Rook Survey 2006. BOS 2006 Annual Report. Brownett, A. (2008). Marsh/Willow Tit Survey 2008. BOS Annual Report 2008. Brownett, A. (2010). Lesser Whitethroat Survey 2010. BOS Annual Report 2010. Brownett, A. (2012). Kestrel Survey 2012. BOS 2012 Annual Report. BTO. (2013). BTO Bird Atlas 2007–11. Retrieved from https://app.bto.org/mapstore/

Bird Trends in the Heart of England, 1977-2016

BTO. (2017). CBC/BBS trends. Retrieved from BTO BirdTrends: https://www.bto.org/about- birds/birdtrends/2017/methods/cbcbbs-trends BTO Garden Bird Watch. (2018). Trichomonosis. Retrieved from https://www.bto.org/volunteer- surveys/gbw/gardens-wildlife/garden-birds/disease/trichomonosis CEH: Rowland et al. (2017). Land Cover Map 2015 Statistics. Retrieved from CEH: https://www.ceh.ac.uk/land-cover-map-2015-statistics Curnow, M. (2016). Corn Bunting Status in the BOS Area. BOS Annual Report 2016. Defra. (2017). Wild Bird Populations in England, 1970 to 2016. Retrieved from https://www.gov.uk/government/statistics/wild-bird-populations-in-england Easterbrook, T. G. (2013). Birds of the Heart of England. Harris, S., Massimino, D., Gillings, S., Eaton, M., Noble, D., Balmer, D., & Procter, D. &.-H. (2017). The Breeding Bird Survey 2016. Thetford: British Trust for Ornithology. Massimino, D., Woodward, I., Hammond, M., Harris, S., Leech, D., Noble, D., . . . Robinson, R. (2017). BirdTrends 2017: trends in numbers, breeding success and survival for UK breeding birds. BTO, Thetford. Retrieved from http://www.bto.org/birdtrends Phillips, H. (2018). The State of Nature in Oxfordshire 2017. Wild Oxfordshire. Retrieved from https://www.wildoxfordshire.org.uk/stateofnature/ Thames and Chiltern Bird Atlas Group. (2016). Thames and Chiltern Bird Atlas. Retrieved from Thames and Chiltern Bird Atlas: http://www.thamesandchilternbirdatlas.org.uk/ Tree Sparrow Villages. (2018). Retrieved from Marlborough Downs Space for Nature: https://www.spacefornature.net/tree-sparrow-villages