Diversity and Abundance of Lice on Speckled Mousebird Colius Striatus and Red-Capped Lark Calandrella Cinerea in Two Ecologically Different Habitats in Central Kenya

Home , Colius, Mousebird, Scarce swift, Speckled mousebird

Diversity and abundance of lice on Speckled Mousebird Colius striatus and Red-capped Lark Calandrella cinerea in two ecologically different habitats in central Kenya

Wamiti, Stephen Wanyoike (B.Sc. Natural Resources Management) Reg. No.: I56/22796/2011 Department of Zoological Sciences

A thesis submitted in partial fulfilment of the requirements for the award of the

degree of Master of Science (Animal Ecology) in the School of Pure and

Applied Sciences of Kenyatta University

October 2014 ii

DECLARATION

Declaration by the Candidate

This thesis is my original work and has not been presented for a degree in any other

University or any other award.

Wamiti, Stephen Wanyoike (I56/22796/2011)

Signature: Date: 16 October 2014

Declaration by the Supervisors

We confirm that the candidate under our supervision carried out the work reported in this thesis.

Dr. Eunice W. Kairu Kenyatta University Department of Zoological Sciences

Signature: Date: 24 October 2014

Dr. Jason D. Weckstein Field Museum of Natural History Department of Science and Education Center of Integrative Research Chicago, Illinois, USA.

Signature: Date: 16 October2014

iii

DEDICATION

This thesis is dedicated to my family, especially to my late father Joseph Wamiti Wabunyi who passed on prior to commencement of fieldwork (May God rest his soul in eternal peace) and to my mother Mary Wanjiru. Together with my siblings, you countlessly gave yourselves in many ways to see me through school. I also lovingly dedicate it to my wife Lucy Njoki for your prayers, patience, understanding, support and being there for me each step of the way, and to our wonderful children, Alex Wamiti and Owen Ndegwa for your cheerful, playful moments - may you grow to love God and be inspired to reach your dreams. Finally, I dedicate this thesis to all those who believe in the pursuit of excellence and richness of learning.

ACKNOWLEDGEMENTS

I am very thankful to my supervisors Dr. Eunice Kairu of Kenyatta University and Dr. Jason

D. Weckstein of FMNH, Chicago for their encouragement, support and guidance. Dr. Jason

Weckstein and his colleague, Dr. John M. Bates, encouraged me to carry on and pursue my interest in avian parasitology and recommended me to the FMNH’s Irene D. Pritzker (IDP)

African Training Fund to whom I owe lots of gratitude for it would not have been possible to pursue my postgraduate studies without this invaluable financial support. Additional fieldwork support was received from Prof. Pablo Veiga and Dr. Vicente Polo, both of

Madrid, Spain. Prof. Irene B. Tieleman of Groningen University (The Netherlands) allowed me to collect data in her ongoing Larks Project in addition to provision of weather data for

Naivasha. I cannot forget the immense contribution of Ms. Heather Skeen for her assistance with DNA extraction and determination of bird’s sex at the DNA Discovery Center &

Pritzker Laboratory at the FMNH, Chicago. I am also very grateful to Dr. Jeno Reiczigel and

Dr. Lajos Rózsa (Budapest, Hungary) for their assistance with insights of QP3.0 software.

Dr. Martin Hromada (University of Prešov, Slovakia) commented on an early version of this thesis. Many thanks to staff at the Zoology Departments of the National Museums of Kenya and Kenyatta University for their unmatched professional assistance. I am indebted to the management of the National Museums of Kenya for approval of my studies. I highly appreciate the support of Nyahururu Bird Club members, the Larks Project research assistants and Francis Muigai of Njabini for helping with data collection and field logistics. My heartfelt appreciation goes to the numerous landowners in Nyandarua and Nakuru Counties who allowed me to trap and examine birds in their farms. I cannot forget the invaluable input of Mrs Sarah Higgins of Naivasha Owls Centre who granted a free access to her camp ground in addition to assisting with logistics in farms where data was collected in Naivasha. v

TABLE OF CONTENTS Page

DECLARATION...... ii DEDICATION...... iii ACKNOWLEDGEMENTS ...... iv LIST OF TABLES ...... viii LIST OF FIGURES ...... ix LIST OF PLATES ...... x ACRONYMS AND ABBREVIATIONS ...... xi ABSTRACT ...... xii

CHAPTER ONE: INTRODUCTION ...... 1 1.1 Background ...... 1 1.2 Problem Statement and Justification ...... 4

1.3 Null Hypotheses (Ho)...... 4 1.4 Research Questions...... 4 1.5 Objectives ...... 5 1.5.1 General Objective ...... 5 1.5.2 Specific Objectives ...... 5

CHAPTER TWO: LITERATURE REVIEW ...... 6 2.1 Parasitism...... 6 2.2. Avian ectoparasites ...... 6 2.2.1 Lice (Insecta: Phthiraptera) ...... 7 2.2.2 Ticks and mites (Arachnida: Acari) ...... 8 2.2.3 Louse flies (Insecta: Diptera, Hippoboscidae) ...... 9 2.2.4 Tropical nest fly (Insecta: Diptera, Muscidae) ...... 9 2.2.5 Fleas (Insecta: Siphonaptera) ...... 10 2.2.6 Other ectoparasite found on birds ...... 10 2.3 Previous and current studies on avian parasites ...... 10

CHAPTER THREE: STUDY AREA, MATERIALS AND METHODS ...... 14 3.1 Description of study areas ...... 14 3.1.1 Nyandarua County ...... 18 3.1.2 Nakuru County ...... 18 3.2 Study species ...... 19 vi

3.2.1 Speckled Mousebird Colius striatus ...... 20 3.2.2 Red-capped Lark Calandrella cinerea...... 21 3.3 Study design ...... 23 3.3.1 Sample size (n) determination ...... 23 3.3.2 Sampling design ...... 24 3.3.3 Selection of sampling sites and study species...... 24 3.3.4 Trapping and processing birds ...... 25 3.3.5 Lice sampling ...... 28 3.3.6 Manipulation and analysis of data ...... 30

CHAPTER FOUR: RESULTS ...... 36 4.1 Occurrence of host species and lice ...... 36 4.1.1 Sample size and temporal distribution of examined hosts ...... 36 4.1.2 Sex and age composition of examined hosts ...... 37 4.2 Distribution of lice among the hosts ...... 38 4.3 Prevalence and infestation intensities of lice ...... 42 4.4 Louse species composition ...... 44 4.4.1 Lice found on Speckled Mousebird ...... 44 4.4.2 Lice found on Red-capped Lark ...... 46 4.4.3 Other ectoparasites recorded on the two host species ...... 49 4.5 Lice species diversity ...... 49 4.6 Variation of lice intensity between host species age groups ...... 50 4.6.1 Variation in intensity of lice between age groups in Speckled Mousebird...... 51 4.6.2 Variations in intensity of lice between age groups in Red-capped Lark...... 53 4.7 Variation in louse intensity between habitats and host species sexes ...... 54 4.7.1 Intensity of lice between habitats ...... 54 4.7.2 Variation of louse intensity between host sexes ...... 55 4.7.3 Association of intensity of lice between sexes and age groups ...... 55 4.8 Relationship between adult host’s body mass and louse abundance ...... 55 4.8.1 Relationship in Speckled Mousebird ...... 56 4.8.2 Relationship in Red-capped Lark...... 56

CHAPTER FIVE: DISCUSSION ...... 59 5.1 Distribution, prevalence and diversity of lice species in the two hosts ...... 59 5.2 Comparison of intensity of lice between host species, age groups and sex ...... 63 5.3 Intensity of lice between habitats ...... 65 5.4 Relationship between adult host’s body mass and louse abundance ...... 65 vii

CHAPTER SIX: CONCLUSION AND RECOMMENDATIONS ...... 67 6.1 Conclusion ...... 67 6.2 Recommendations ...... 70 6.2.1 Species management ...... 70 6.2.2 Further research ...... 71

REFERENCES ...... 73

APPENDICES ...... 80 Appendix I: Descriptive statistics for lice infestation for each of Speckled Mousebird’s sampling sites...... 80 Appendix II: Descriptive statistics for lice infestation for each of Red-capped Larks’s sampling sites...... 81

viii

LIST OF TABLES

Page

Table 3.1 Some information on environmental parameters of the two study areas... 14

Table 3.2 Monthly averages for weather observations during the study period (September – December, 2012) for three of the sampling sites. Data courtesy of Larks Project ……………………...……………………….... 16 Table 4.1 Hosts trapped and quantitatively examined for lice in Nyandarua and Nakuru in each month during the study period………………………….. 36 Table 4.2 Age and sex compositions of examined hosts at both study areas………. 37 Table 4.3 Descriptive statistics for lice infesting Speckled Mousebird and Red- capped Lark in Nyandarua and Nakuru Counties of Kenya. ……………. 43 Table 4.4 Overall descriptive statistics of the two louse genera on Speckled Mousebird …………………………………………………………...…... 45 Table 4.5 Descriptive statistics for the two genera of lice found on Speckled Mousebird …………………………………………………………...…... 45 Table 4.6 Overall descriptive statistics of the three louse genera on Red-capped Lark …………………………………………………………………...… 48 Table 4.7 Descriptive statistics for infestation by the three genera of lice on Red- capped Lark. …………………………………………………………...... 48 Table 4.8 Diversity indices of the louse genera found on Red-capped Lark and Speckled Mousebird ………………………………………………..….... 50 Table 4.9 Summary descriptive statistics for lice on the four age groups of Speckled Mousebird ………………………………………………..….... 51 Table 4.10 Mann-Whitney pairwise comparisons matrix of variation of louse intensity between the four age groups of Speckled Mousebird .………... 52 Table 4.11 Summary descriptive statistics for lice on the four age groups of Red- capped Lark ………...…………………………………………………… 53 Table 4.12 Mann-Whitney pairwise comparisons of variation of lice intensity between the four age groups of Red-capped Lark ……………...……….. 53

LIST OF FIGURES Page

Figure 3.1 Map of Kenya showing location of the study areas in Nakuru and Nyandarua Counties, and distribution of sampling sites for both species of birds…………………..…………………………..………… 17

Figure 4.1 Distribution of lice on Speckled Mousebird …………………….….…. 38

Figure 4.2 Distribution of lice on Red-capped Lark ………………..…………….. 39

Figure 4.3 Distribution of lice on Speckled Mousebird with transposed normal curve ………………………………………...………………………… 39 Figure 4.4 Distribution of lice on Red-capped Lark with transposed normal curve 40

Figure 4.5 Normal probability plot for distribution of lice on Red-capped Lark…. 41

Figure 4.6 Percentiles of distribution of lice on Red-capped Lark. ..………….….. 41

Figure 4.7 Population of the louse genera found on Speckled Mousebird, indicating dominance of Colilipeurus sp. over Colimenopon sp …….... 46 Figure 4.8 Population of the three genera of lice found on Red-capped Lark, indicating dominance of Menacanthus sp….………………. ……….... 49 Figure 4.9 Variation in louse intensity in the four age groups of Speckled Mousebird ………………………………………………………….….. 52 Figure 4.10 Variation in louse intensity in the four age groups of Red-capped Lark. 54

Figure 4.11 Relationship between adult’s host body mass and louse abundance in Speckled Mousebird …………………….………….……………….… 57 Figure 4.12 Relationship between adult’s host body mass and louse abundance in Red-capped Lark ………………………………...…………….………. 57 x

LIST OF PLATES

Page

Plate 1: Close-up photograph of an adult Speckled Mousebird (with the crest

lowered)………………………………………………………………..….. 22

Plate 2: An adult male of the Red-capped Lark………………………………..… 22

Plate 3: PCR gel showing results for sex: two bands = female (♀); single band =

male (♂) ………………………………………………………….……… 28

Plate 4: Photographs showing lice genera found on Speckled Mousebird. A:

Colilipeurus sp. (♀); B: Colimenopon sp. (♂)…..…….………………… 44

Plate 5: Photographs showing lice genera found on Red-capped Lark. A:

Menacanthus sp. (♀); B: Philopterus sp. (♀); C: Ricinus sp. (♀)...... …… 47

ACRONYMS AND ABBREVIATIONS

CHD Chromo-helicase-DNA-binding

DNA Deoxyribonucleic Acid df Degrees of freedom (i.e. number of categories/observations minus one)

FAO Food and Agricultural Organisation of the United Nations

FMNH Field Museum of Natural History, Chicago

FTA Filter cards used to preserve a small amount of blood as a dry spot.

H Kruskall-Wallis Statistic

H5N1 HPAI (see below) virus strain that causes avian influenza

HPAI Highly Pathogenic Avian Influenza

IUCN International Union of Conservation of Nature and Natural Resources

KARI Kenya Agricultural Research Institute mm, g Measurements in millimetres and grams respectively

PAST Paleontological Statistics software (Version 2.7)

PCR Polymerase Chain Reaction

QPWeb3.0 Quantitative Parasitology software on the web (version 3.0)

U Mann-Whitney Statistic

χ² Chi-square Statistic xii

ABSTRACT

Parasites play an important role in ecosystems including shaping the populations and communities of their hosts. Majority of arthropod parasites transmit vector-borne zoonotic diseases, some of which are transmissible to humans and livestock. Birds are a host to a variety of arthropod parasites. Despite their importance, parasites continue being excluded in most ecological inventories. For example, the diversity of avian fauna in Kenya is fairly well known yet little is known about their ectoparasites. The aim of this study was to determine the diversity and abundance of lice of two endemic subspecies of birds, Speckled Mousebird Colius striatus kikuyuensis and Red-capped Lark Calandrella cinerea williamsi in two adjacent but ecologically different ecosystems: the cooler highlands of Nyandarua County and the warmer and lower altitude Naivasha area of Nakuru County. The two hosts were chosen because they are widely distributed in both study areas, exhibits varying behaviour and occupy specific niches. Lice were collected from 269 Speckled Mousebirds and 327 Red- capped Larks that were trapped using mist nets, and quantitatively examined using the dust- ruffling technique. A small amount of blood (c.100µl) was preserved as a dry spot from which DNA was extracted to determine the host’s sex through PCR protocol targeting the CHD gene located on the avian sex (Z) chromosome. Two genera of lice, Colilipeurus sp. and Colimenopon sp., were recorded on Speckled Mousebird. Red-capped Lark had three lice genera: Philopterus sp., Menacanthus sp. and Ricinus sp., the first two being new host records. Louse distribution among hosts was aggregated (Poulin’s discrepancy index D: Speckled Mousebird 0.571, Red-capped Lark 0.909). Louse prevalence was high in Speckled Mousebird (90%) compared to Red-capped Lark (17%). Prevalence between the host species was significantly different (unconditional exact test p <0.0001). Louse intensity was significantly different among four age groups for both host species (Speckled Mousebird H = 21.72, p <0.0000; Red-capped Lark: H = 10.05, p = 0.017). Intensity of louse infestation between sexes was not significantly different in both hosts species (Speckled Mousebird U = 6288, p = 0.179; Red-capped Lark: U = 335.5, p = 0.359). There was a weak inverse relationship between host’s body mass and louse abundance though not statistically different (Speckled Mousebird: rho = •0.49, p = 0.4749; Red-capped Lark: rho = -0.035, p = 0.61). The two new host-parasite associations reported for Red-capped Lark suggest that there is more information not yet known about Kenyan avifauna parasites. The findings indicate that prevalence of lice is high in social species, such as Mousebirds, compared to the less social species like Red-capped Lark. This is probably because the parasite can spread fast due to regular body contact. The two hosts studied do not share lice although same genera were recorded at both habitats. Parasitic patterns, prevalence and intensity were different between lice genera, habitats and host species. It is therefore important that wildlife and livestock systems put into consideration the role of environmental factors, habitat features and behaviour of host species as these can have significant influence on parasite patterns. xiii

DEFINITION OF TERMS

The following terminologies are used in this thesis to report and describe the parasite data.

They follow Margolis et al. (1982), Rékási et al. (1997), Rózsa et al. (2000) and Nelder &

Reeves (2005).

Sample size Refers to the number of hosts species individuals examined. This is

usually denoted by ‘n’.

Abundance The number of conspecific ectoparasites living on (or in) any host

(abundance is always ≥ 0).

Mean abundance This is the mean number of parasites found on (or in) all hosts (involves

the zero values of uninfected hosts).

Intensity The number of conspecific parasites living on (or in) an infected host.

(Intensity is always > 0). It is frequently expressed as a numerical range.

Mean Intensity The total number of individuals of a particular parasite species on (or in)

a sample of a host species ÷ number of infected individuals of the host

species in the sample (= mean number of individuals of a particular

parasite species per infected host in a sample). Uninfected hosts are

excluded and thus the mean intensity value is highly dependent on a few

extremely infected hosts.

Prevalence This is the proportion (usually expressed as a percentage, %) of hosts

within the sample of hosts examined that is infected with a particular

parasite species i.e. number of hosts infected ÷ number of hosts

examined x 100.

xiv

The definition of host species age groups i.e. juvenile, immature, sub-adult and adult, follows

Jackson (2001).

Juvenile Bird in fully juvenile plumage or with no more than c.10% adult or

immature body plumage or wing coverts; often shows large gape

flanges; bare parts (eyes, bill, and tarsus) colour typically not adult.

Immature Bird is unlikely to be sexually mature, clearly in mixed juvenile and

adult body plumage and has new adult body feathers.

Sub-adult Bird known definitely to be in its first adult-type body plumage, with

c.98-100 % adult body plumage but has retained some juvenile or

immature flight and tail feathers and not developed full colours of

adult’s bare parts.

Adult Bird known definitely to be in full adult plumage and highly likely to be

sexually mature; body, wing, tail and colour of eyes, legs and bill fully

adult.

CHAPTER ONE

INTRODUCTION

1.1 Background

Biodiversity inventory is a key component in conservation. Inventories can be used as baselines for current and future species loss and turnover assessments (Sodhi & Ehrlich

2010). However, most biological inventories focus on vertebrates, plants, and arthropods that are of economical, medical and veterinary importance to humanity, livestock and wildlife.

Birds and mammals are hosts to a variety of arthropod parasites. Some of these parasites are vectors for zoonotic diseases (Nedler & Reeves 2005; Oguge, Rarieya & Ondiaka 2009).

Storer & Usinger (1957) gave an account of arthropods that transmit pathogens. They included lice Trichodectes canis which transmits the domestic dog tapeworm Dipylidium caninum, and ticks such as Boophilus annulatus that transmit Babesiosis (Babesia bigemina) in cattle. To fully understand and control zoonotic diseases in resolving clinical problems, parasitic arthropods and their hosts should be studied together (Nedler & Reeves 2005).

Sabuni et al. (2010), while studying ectoparasite fauna in free-range chickens in the Embu

County of Kenya, found that ectoparasite infestation had a negative effect on the system’s productivity. Hence, parasites should be of great economic concern since they can put the livelihoods of human populations at risk.

Since the early to mid-2000s, there has been a growing concern that wild birds such as waterfowls could transmit the HPAI virus not only to poultry but also to humans. In 2003, the outbreak of the H5N1 strain of the HPAI virus in Asian, African, and European poultry led to deaths of humans, poultry and wild birds (FAO 2007). This caused great panic in countries along major bird migration routes, such as those within the eastern Africa Rift Valley flyway like Ethiopia, Sudan, Egypt and Kenya. There has been no incidence of H5N1 in Kenya, 2 unlike in some African countries including Cameroon, Ivory Coast and Nigeria where it was confirmed in poultry rather than in wild birds (FAO 2007).

Information on avian diseases and parasites is of great practical value to wildlife and field biologists (Cooper & Eley 1979). This is because parasites play an important role in ecosystems and have direct and indirect effects on the quality of life of their hosts, yet they have continuously been left out in community ecology research and evaluation of habitat quality for vertebrates (Loye & Carroll 1998; Hatcher & Dunn 2011). The effects of parasites on avian hosts range from sub-clinical infections to death, and can have complications on the bird’s ecology, evolution as well as conservation of species and populations (Whiteman &

Parker 2005; Cunha et al. 2008). The exact effect of most parasites on their hosts is not well understood. For example, Whitman & Wilson (1988) observed that the health of their avian hosts were not strongly affected by the presence of louse flies and contrasts Weddle (2000) observations that broods of House Sparrow (Passer domesticus) with high mean ectoparasite loads had lower overall body masses than those from broods with relatively low ectoparasite loads. Cooper (2002) also observed strong negative health effects of tick infestations on a

Lanner Falcon (Falco biarmicus), which had gross lesions, haemorrhage, and necrosis in the areas of parasite attachment.

Kenya has eight (8) bird species recognized as national endemics (Bennun & Njoroge 2001) that currently face risk of extinction due to continuing habitat loss. According to BirdLife

(2013), three of these species (Turdus helleri, Apalis fuscigularis and Zosterops (poliogaster) silvanus) are classified as Critical; three others (Macronyx sharpei, Cisticola aberdare and

Ploceus golandi) as Endangered, while Turdoides hindei is Vulnerable and Mirafra williamsi is described as Data Deficient. 3

Indeed, it is seldom appreciated that the extinction of vertebrate species also results in the extinction of all associated host-specific parasites (Evans, Garrison & Schlager 2003; Koh et al. 2004). It is possible that some of Kenya’s endemic vertebrate avifauna harbours host- specific parasites that are therefore also endemic and potentially threatened. Parasites are key components of biodiversity and should be treated as so. The overwhelming majority of animal conservation projects are focused on vertebrates, despite most of the animal species

(30-70%) on Earth being parasitic invertebrates (Poulin, 2004; Poulin & Morand 2004;

Mihalca, Gherman & Cozma 2011). With many of these parasite species being highly host- specific, it is possible that the parasites of threatened vertebrate hosts such as Kenya’s endemic avian taxa also face similar threats as their hosts.

However, ecologists and conservationists have tended to ignore parasites in their studies despite the high level of direct and indirect threats to vertebrate hosts (Whiteman & Parker

2005; Hatcher & Dunn 2011). To date, only one louse species (Haematopinus oliveri – an anoplura whose host is the Pygmy Hog Sus salvinus), is listed on the IUCN Red List, whereas hundreds of mammalian and avian hosts were defined as Extinct in the Wild or Critically

Endangered (Evans et al. 2003). Many authors for example, Price (1980), Timm & Clauson

(1987), de Meeûs, Michalaki & Renaud (1998), Windsor (1998), de Meeûs & Renaud (2002) and Mihalca, Gherman & Cozma (2011) recommend that IUCN should consider listing all specific symbiotic species (mutuals, commensals, parasites) in threat categories as Co- endangered. However, to make these kinds of recommendations, there is prior need to characterize parasite biodiversity and understand which parasites are generalists and which ones are host-specialists thus making them prone to co-extinction. This study therefore aimed at investigating the diversity and abundance of lice fauna of two Kenyan endemic bird subspecies in two ecologically different habitats. 4

1.2 Problem Statement and Justification

Kenya is one of the richest African countries in bird species diversity with 1,100 species recorded by 2009. Birds are hosts to many parasites but barely a handful of them have been examined for their parasites in Kenya. Given the high diversity of avian hosts in Kenya, it is likely that there are many parasite species and host/parasite associations not yet known or recorded. Parasite biodiversity (often called invisible fauna) should be given as much attention as their hosts since they have an intimate, evolutionary relationship. Recent studies have shown that parasites play a significant role in ecosystems’ food relationships, and in some cases, as keystone species. This study therefore investigated the diversity of lice in two bird subspecies endemic to Kenya, Colius striatus kikuyuensis and Calandrella cinerea williamsi, in parts of Nyandarua and Nakuru Counties as an important step in understanding

Kenyan wild birds host/parasite associations. The two bird subspecies are widely spread and occurs in both study areas, and occupies different ecological niches hence suitable for a comparative study. Prior to this study, little was known about the lice that parasitise these hosts. The results obtained in this study provide new information that enriches our knowledge on our natural heritage and the reference collection held at the National Museums of Kenya.

1.3 Null Hypotheses (Ho)

1. Intensity of lice infestation does not vary with age and sex of host species.

2. Intensity of lice infestation does not vary between the two habitats.

3. There is no relationship between louse abundance and adult host body mass.

1.4 Research Questions

1. Which lice species are associated with Colius striatus kikuyuensis and Calandrella

cinerea williamsi in the study areas? 5

2. Does intensity of lice infestation vary with sex and age group of the host?

3. Does intensity of lice infestation differ between the habitats?

4. Is there a relationship between adult host’s body mass and louse abundance for the

two host species?

1.5 Objectives

1.5.1 General Objective

The overall goal of this study was to assess the lice fauna infesting two bird subspecies occupying different habitats in parts of Nakuru and Nyandarua Counties in Kenya.

1.5.2 Specific Objectives

1. To carry out a survey of lice species associated with Colius striatus kikuyuensis

and Calandrella cinerea williamsi in two ecologically different habitats.

2. To determine whether intensity of lice infestation is affected by sex and age of

the host.

3. To determine whether intensity of lice infestation vary between the habitats.

4. To investigate whether there is any correlation between body mass of adult hosts

and abundance of lice.

CHAPTER TWO

LITERATURE REVIEW

2.1 Parasitism

Parasitism is defined as a strict and intimate relationship between two organisms where one, the parasite, depends and directly benefits (for example derives food, takes shelter and reproduces on or in another organism) at the expense of the other, the host (Rothschild &

Clay 1957; Romoser 1981; Hatcher & Dunn 2011). Parasite can live on the host’s skin or within its body and are termed external/ectoparasite and internal/endoparasite, respectively.

Parasites may spend all or part of their life on or inside the host (Starr, Evers & Starr 2008).

Parasites are now being recognised for the important part they play in influencing species interactions and consequently affecting ecosystem function, including their role as keystone species (Hatcher & Dunn 2011). They are also increasingly becoming subjects of ecological studies for example, Bush, Reed & Maher (2013) studied the lice of avian communities in fragmented forests in China to understand how parasites are linked to their hosts and the host’s environment.

2.2. Avian ectoparasites

Various well known groups of ectoparasites have been reported on birds for example, Peters

(1930), Ledger (1968), Peirce & Backhurst (1970), Cheke (1972, 1978), Hill (1994), Price et al. (2003) and Edosomwan & Amadasun (2008). The early works on avian feather lice was largely on taxonomy and systematics where genus and species were (and still are) being described, reviewed or re-described, for example, Clay (1950, 1965, 1966), Timmermann

(1951), Foster (1969), Palma & Pilgrim (1987), Price & Clayton (1997) and Nasser et al.

(2014). Interest in various aspects of the parasites has grown over the years with an enormous literature being available on various aspects such as ecology (Bush, Reed & Maher 2013; 7

Rózsa, Rekasi & Reiczigel 1996), field sampling techniques (see section 3.3.5); parasitic data analysis (Reiczigel, Rózsa & Reiczigel 2013) and experimental (Clayton et al. 2005). Birds are a host to a variety of arthropod ectoparasite including feather lice, ticks, several types of mites, louse fly, tropical nest fly and fleas (Clayton & Moore 1997), and are discussed in detail below.

2.2.1 Lice (Insecta: Phthiraptera)

Lice are small (length <0.5-8mm) wingless, dorso-ventrally flattened, obligate ectoparasites belonging to Class Insecta and Order Phthiraptera (previously known as Mallophaga) parasitizing birds and some mammals (Clayton, Adams & Bush 2008). They are only group of insects that show complete commitment to parasitism (Askew 1971). Phthiraptera constitutes both the chewing and sucking lice. There are four sub-orders, three of which (the

Amblycera, Ischnocera and Rhynchophthirina) are known as the chewing or biting lice, and the fourth (Anoplura) as sucking lice (Evans, Garrison & Schlager 2003; Price et al. 2003).

Anoplura and Rhynchophthirina are restricted to mammals whereas Amblycera and

Ischnocera are known from both birds and mammals (but are not yet known to attack humans).

Lice are obligate ectoparasites and are the only parasitic insects that complete all of their life cycle on a single host by feeding on the hosts tissues (Johnson & Clayton 2003;

Szczykutowicz et al. 2006). The majority of avian chewing lice feed on secretions, feathers, dead skin (dermal scales) and skin products, and some feed on blood with some species of

Amblycera feeding exclusively on it (Borror, Triplehorn & Johnson 1989; Johnson et al.

2003; Clayton, Adams & Bush 2008). The female lays eggs (also called nits) and attaches them to a feather barb of the host, close to the host’s skin, using a drop of glandular cement

(Evans, Garrison & Schlager 2003). Egg cases can be used in louse species identification 8 since their morphology and location of attachment is species-specific (Eichler 1963 cited in

Foster 1969). The entire life cycle, lasting one to three weeks from egg to adult, takes place on the host. An adult louse lives for about one month. Lice are generally thought to show high host-specificity although recent studies have shown that there is a lot of variation in host-specificity for example, Bueter et al. (2009) and Johnson et al. (2011). They cause considerable irritation, and heavily infested animals appear run-down and emaciated, and are important vectors of diseases (Borror, Triplehorn & Johnson 1989). This study focused on lice because their populations are profoundly affected by variation in temperature and humidity near the host skin (Johnson et al. 2003) and is one of the extensively studied ectoparasite of birds both under laboratory and field conditions. Other than the feather

(chewing) lice, we also have quill lice that live inside the quills of feathers and pouch lice that live inside the gular pouches of Pelicans and Cormorants (Clayton & Moore 1997).

2.2.2 Ticks and mites (Arachnida: Acari)

Ticks are Arachnids together with the spiders and scorpions. There are two families of ticks,

Ixodidae (hard ticks) and Argasidae (soft ticks). Ixodidae are of veterinary importance

(Walker, 1974). Ticks are blood feeding external parasites of mammals, birds, amphibians and reptiles throughout the world (Mihalca, Gherman & Cozma 2011; Vredevoe 2012) and are important pests of domestic animals and prominent parasites of humans (Vatansever et al.

2008) where they cause paralyses and toxicoses, irritation and allergy, wounds, and haemorrhage. They are vectors of a broad range of viral, bacterial, and protozoan pathogens

(Estrada-Peña & Jongejans 1999) transmitting the widest variety of pathogens of any blood sucking arthropod. Tick-borne pathogens include bacteria, protozoa, and viruses (Vredevoe

2012). Schwarzova et al. (2006) detected Borrelia burgdorferi, a spirochaete bacterium that causes the infectious Lyme disease, from ticks sampled from four migratory bird species in 9 many countries and continents. From the human perspective, ticks are potentially the most visible and damaging ectoparasite on birds (Hilton 1991). Ticks are also one of the best- known groups of parasites (Petney et al. 2011). There are several types of mites that live in and on birds; some being parasitic whereas others are not and live as mutualists with their hosts. Avian mites include quill mites, nasal mites, feather mites and bird-nest mites. Feather mites (Astigmata) are obligatory permanent ectoparasites living exclusively on birds. They occur on various parts of the plumage, mainly on flight feathers and large coverts of the wings, sometimes in the downy layer and on the skin (Dabert & Mironov 1999).

2.2.3 Louse flies (Insecta: Diptera, Hippoboscidae)

Louse flies, also known as hippoboscids, are closely related to tsetse flies, Glossina spp.

Hippoboscid and tsetse flies share the characteristic that the females retains the larvae in a

‘uterus’ until it is fully grown and ready to pupate. Adult hippoboscids show various adaptations to a parasitic mode of life such as flattened and leathery body, strong legs with claws to hold on to the host, and sometimes flightlessness (Downes 1971; Hutson & Oldroyd

1980). Hippoboscids are known to give a ‘ride’ to chewing lice from one host to another, a phenomenon known as phoretic association (Downes 1971) and lice may use this association as a means of dispersal. They tend to abandon a struggling host and is therefore not suitable difficulty to sample them using mist nets (Clayton & Moore 1997).

2.2.4 Tropical nest fly (Insecta: Diptera, Muscidae)

Larvae of these flies are obligatory, blood-sucking nest ectoparasites causing myiasis in nestling birds and have been recorded from about 20 species of birds in Africa south of the

Sahara (Ledger 1968; Pont 1980; Gichuki 1984) found and described larvae infesting nests and cloaca of Speke’s Weaver Ploceus spekei and Baglafecht Weaver P. baglafecht nestlings in various breeding colonies in Nairobi, Kenya. Generally, not much is known about them. 10

2.2.5 Fleas (Insecta: Siphonaptera)

Fleas are small, wingless insects, with laterally flattened body making it easy for them to slip through the fur or feathers of their host. Adult fleas are blood-sucking ectoparasites of mammals or birds (Burton 1975). They are most numerous on hole-nesting bird families such as bee-eaters (Meropidae), kingfishers (Alcedinidae) and hornbills (Bucerotidae). However, only a few flea species are confined to one host, e.g. Ceratophyllus styx of Rock Dove

(Columba livia) and Sand Martin (Riparia riparia), with most flea species infesting a variety of hosts. Hen flea (Ceratophyllus gallinae) lives on a variety of birds and mammals (Burton

1975). Adult fleas may transmit bacterial, viral, protozoan and other pathogens to the host while feeding (Uusiku 2007). Fleas also spread or transmit a number of diseases e.g. Murine typhus (rickettisial disease) and plague from infested rodents (Storer & Usinger 1957).

2.2.6 Other ectoparasite found on birds

These include “bedbugs” (Hemiptera: Cimicidae), which are known to live in the nests of some avian species where they are mostly active at night. Mosquitos (Diptera: Culicidae) of the genus Coquillettidia, which are known to transmit avian Haemosporidian pathogens in

Africa (Njabo et al. 2009), and blackflies (Diptera: Simuliidae), which are commonly referred to as buffalo gnats and are tiny (2-3mm long) flies whose adult females parasitize mammals and birds. Black flies inflict painful bites on humans (Hill 1994) and can transmit avian blood parasites such as Onchocerciasis, or “River Blindness” (Udall 2007).

2.3 Previous and current studies on avian parasites

African avian parasite biodiversity has been studied in the past. Examples include Cheke

(1972) and Cheke (1978) who studied the birds of Cherangani montane forests in Kenya. The two studies give an account of about thirty host species and their associated parasites. 11

Moriearty, Pomeroy & Wanjala (1972) examined endo- and ectoparasites of Marabou Stork

Leptoptilos crumeniferus in Uganda. Ledger (1968) collated ectoparasite records from

Coliiformes, the mousebirds where five taxa (lice, ticks, mites, flies and fleas) are reported.

Other work dedicated to past Kenyan avian parasites includes Meinertzhagen (1950), Johnson

(1963) and Bennett & Herman (1976) while recent work includes Wamiti & Weckstein

(unpubl. data), and Skoracki, Hromada & Wamiti (2011), the latter described a new species of quill mite Syringophilopsis dicruri (Acarina: Syringophilidae, ex. Dicrurus adsimilis) and a variety of new host records for this mite family in Kenya. While describing two new species of lice from the American Black Swift (Cypseloides niger), Price & Clayton (1997) examined a small number of specimens including a single male ex. Scarce Swift

(Schoutedenapus myoptilus) collected in Kenya, and given the wide geographical separation of the two hosts, the Kenyan material was relegated to unknown status awaiting collection of additional material, emphasising need for rigorous collecting of ectoparasite not only in

Kenya but world over to enable taxonomists resolve queries.

Elsewhere, especially in the Americas, Europe, Australia and New Zealand, literature on different aspects of avian parasitology is relatively extensive, but still not at the same scale as the enormous biodiversity encompassed by parasites. Even here, new species of ectoparasite continue to be discovered, for example, Valim & Weckstein (2013) described ten new species of genus Myrsidea from avian hosts in Amazonian Brazil. In regions, such as Kenya, where very little is known about avian ectoparasite biodiversity, ecology, and evolution in general, there is still a lot to learn, especially given that the bird species diversity is high compared to most other regions of the world.

The majority of ornithological research in Kenya has been on areas such as bird ringing and migration for example, Lack (1983b), Backhurst & Pearson (1984) and Bennun (1987), species lists and inventories for example, Bennun (1991), Bennun & Waiyaki (1992b),

Njoroge et al. (2008), Wamiti, Malaki & Mwangi (2008) and Wamiti et al. (2010), and ecology and conservation for example, Muchai (1997) and Bennun & Njoroge (1999, 2001).

Dietsch (2005) points out that one of the gaps in knowledge is on ectoparasite distribution and frequency of infestation among hosts of wild birds found in tropical habitats. The biology and habits of the chewing lice are also poorly studied and thus little is known about the frequency and distribution of these parasites across geographic regions and on hosts (Ash

1960). Wamiti & Weckstein (unpubl. data) recommended integration of ectoparasite surveys into ongoing avian research and biodiversity inventories in Kenya.

Given the paucity of information on Kenyan avian ectoparasite fauna, it is apparent that immediate work should embark on studies that lead to understanding of host-parasite associations, continuous examination of hosts so that all taxa hosted by wild birds in Kenya are known, and study various parasitic patterns and how these may be influenced of affected by host species’ behaviour, sex, age and habitat (ecological parameters). Future work may investigate how changes in the host’s environment affect parasite biodiversity.

Knowledge on distribution and conservation status of the avifauna of both study areas and their habitats is relatively well studied presently. Such work in Naivasha and the riparian woodlands and swamps around the lake includes Tyler (1991), Henderson & Harper (1992),

Virani, Thorson & Harper (1997) and Bennun & Njoroge (2001). In Nyandarua, Bennun &

Njoroge (2001) report on Kinangop’s distinctive avifauna whereas Wamiti, Malaki & 13

Mwangi (2008), Wamiti (2010) and Wamiti et al. (2011) report on birds of Nyahururu area.

Ndang’ang’a et al. (2013) conducted a study on avian foraging behaviour as an ecosystem service in the County. Past ornithological research in Kinangop includes some aspects of the ecology and conservation status of Sharpe’s Longclaw Macronyx sharpei (Muchai 1997) and land use and how it affects the native grassland habitat (Ndang’ang’a 2001).

CHAPTER THREE

STUDY AREA, MATERIALS AND METHODS

3.1 Description of study areas

This study was carried out in parts of Nakuru County (Naivasha and Soysambu) and

Nyandarua County (Kinangop and Nyahururu), in the central highlands of Kenya. The two areas are adjacent to each other but with different ecological characteristics. They were chosen because of a number of reasons. Firstly, BirdLife International has listed a few sites in these study areas as Important Bird Areas (IBAs). IBAs are sites that are not only important for birds’ conservation but also for other biodiversity. Secondly, many bird species (including the study species) are common in both sites, which was ideal for the comparative component of this study. Last but not least, the bird fauna of both areas are studied widely and thus the distribution of study species is well known.

A summary of the general ecological characteristics of the two study areas is provided in table 3.1 below after Muia et al. (2011) and Pratt & Gwynne (1977). The values show the distinctiveness of each study area for each of the parameter.

Table 3.1: Some information on environmental parameters of the two study areas.

Parameter \ Study Area Nyandarua Nakuru

Air Temperature (0c) 12-25 14-34

Elevation (meters) 2340-2700 900-1800

Rainfall (mm per annum) 1100-2700 600-1200

The general area close to the sampling sites where birds were trapped and examined had different weather characteristics. Humidity (%), rainfall (mm) and temperature (0C) were measured using weather stations (Alecto WS-3500, Netherlands) set up in three localities

(table 3.2) by the Larks Project with who availed this data. Data was recorded daily, both minimum and maximum values from which monthly averages were calculated for each month of the study period (Sept. – Dec. 2012). There was a noticeably high relative humidity recorded for South Kinangop (Njabini) in Nyandarua. A low value of relative humidity indicates a dry environment while a higher value indicates a rather wet environment. Since no birds (Red-capped Larks) were examined in Njabini, no parasitic patterns could be compared with Mt Longonot Plains in Naivasha where the same host species were caught and weather data collected. There was no great variation in temperatures although higher values were recorded in Naivasha (Mt. Longonot plains) compared to the two sites in Nyandarua. Least precipitation was recorded in Naivasha while South Kinangop (Njabini) remained wet throughout the study period. No weather data was available for the northern part of

Nyandarua County (Nyahururu). 16

Table 3.2: Monthly averages for weather observations during the study period (September –

December, 2012) for three of the sampling sites. Data courtesy of Larks Project.

North Mt. Longonot South Kinangop Study Sites Kinangop Plains (Kedong (Njabini) (Murungaru) Ranch) Weather Parameter Month Min. Max. Min. Max. Min. Max. Sept. 7.29 27.73 4.99 22.60 8.56 28.76

Oct. 8.34 26.34 5.65 23.58 10.38 29.69 Temperature (oC) Nov. 9.80 25.72 5.73 24.89 9.40 30.35

Dec. 7.12 27.75 5.49 25.36 10.17 31.90

Sept. 20.00 46.27 93.54 99.00 20.00 48.17

Relative Humidity Oct. 20.00 38.57 92.70 99.00 20.00 43.35 (%) Nov. 20.00 52.57 92.20 99.00 20.00 38.92

Dec. 20.00 43.19 91.42 99.00 20.00 43.92

Sept. 2.39 2.05 0.60

Oct. 3.03 2.04 1.30 Rainfall (mm) Nov. 1.95 2.57 0.40

Dec. 0.08 4.44 0.10

Figure 3.1: Map of Kenya showing location of the study areas in Nakuru and Nyandarua Counties, and distribution of sampling sites for both species of birds (Circles: Red-capped Lark; Squares: Speckled Mousebird). 18

3.1.1 Nyandarua County

Nyandarua is one of the 47 administrative Counties in Kenya and is sandwiched between the western slopes of the Nyandarua Mountains (Aberdares) and the eastern edge of the Great

Rift Valley. Bennun & Njoroge (1999) listed Kinangop grasslands as one of Kenya’s

Important Bird Areas (IBAs) due to the presence of bird species of global conservation concern. Lake Ol’ Bolossat became an IBA in March 2008 (Wamiti, Malaki & Mwangi

2008). According to FAO (1996) and Pratt & Gwynne (1977), Kenya is divided into seven agro-ecological zones. Nyandarua is classified as humid to sub-humid agro-ecological Zone

II, the highlands. The high elevation and rainfall regimes allows for forestry and intensive agriculture of crops like pyrethrum and vegetables. The landscape is mainly comprised of highland moist forests and grasslands, together with cultivated land (Pratt & Gwynne 1977), with characteristic tussock grasses in most wet areas of Nyandarua being Cymbopogon nardus, Eleusine jaegeri, Hyparrhenia hirta and Pennisetum hohenackeri (Bennun &

Njoroge 1999). Sites for both habitats where sampling was carried out are in the appendices.

The grasslands of the central Kenya highlands provide habitat for globally-threatened bird species such as the Kenyan high-altitude grassland endemic Sharpe’s Longclaw (Macronyx sharpei) (Muchai 1997; BirdLife 2002; Muchai et al. 2002; Muchane, Lens & Bennun 2002;

Wamiti, Malaki & Mwangi 2008). BirdLife (2000) describes grasslands as one of the most important habitats for the world’s threatened bird species.

3.1.2 Nakuru County

Nakuru County is located in the central part of the Great Rift Valley. FAO (1996) and Pratt

& Gwynne (1977) designate Nakuru as a dry, sub-humid to semi-humid area in agro- ecological zone III-IV. Several indigenous species of Acacia trees (for example Acacia 19 drepanolobium, A. gerradii and A. xanthophlea) are found in this zone. Euphorbia trees occur in some of the drier parts whereas Tarchonanthus spp. is a common bush. Native grasses include Themeda triandra and Pennisetum spp.

The area around Naivasha and between Nakuru town and Naivasha has intensive cattle ranching as well as nomadic pastoralism and wildlife conservation and tourism. In Naivasha, farming of flowers and horticultural crops is common. Prominent physical features near

Nakuru and Naivasha towns include Ramsar site Lakes Nakuru, Elementaita and Naivasha,

National Parks (Hell’s Gate, Mt. Longonot and Lake Nakuru), Menengai Crater, Mau forest and Malewa River. Lake Naivasha is not only listed as a Ramsar Site (MEMR 2012) but also as a World Heritage Site (UNESCO 2011). The area around and inside Hell’s Gate and

Menengai crater are being developed for geothermal electricity generation, a development that face resistance from conservationists and civil society.

Interesting avian species inhibiting the Acacia woodlands include the near-threatened Grey- crested Helmetshrike (Prionops poliolophus), whereas the diverse waterbird community in the Lake includes the local and rare Saddle-billed Stork (Ephippiorhynchus senegalensis), the endangered and Palaearctic passage migrant Basra Reed Warbler (Acrocephalus griseldis) and the resident African Fish Eagle (Haliaeetus vocifer).

3.2 Study species

This study investigated the lice (Insecta: Phthiraptera) that parasitize Speckled Mousebird and Red-capped Lark. Although there were many other species of birds in the study areas, the two hosts were chosen for this study for various reasons. The study population of each of these species is a subspecies endemic to Kenya’s central highlands i.e. Speckled Mousebird

Colius striatus kikuyuensis and Red-capped Lark Calandrella cinerea williamsi. The two 20 species common and widely distributed in both study areas and occupies different niche with

Speckled Mousebird living in bushes, forest edges, and farmlands. This species too is adapted to habitat alterations (Yamagishi & Kabango 1986; Keith et al. 1992). The Red-capped Lark prefers open country habitats especially short grasslands with some bare ground

(Zimmerman, Turner & Pearson 1996). In Nyandarua, birds were mainly trapped in recently ploughed fields or fallow agricultural land. The two species exhibit different social behaviour where Speckled Mousebird lives in social groups throughout their lives (Yamagishi &

Kabango 1986; Keith, Urban & Fry 1992), while Red-capped Lark occur in pairs during the breeding season and becomes gregarious during the non-breeding season (Keith, Urban &

Fry 1992). As is the case with many other Kenyan wild birds, the lice and ectoparasite of these two host subspecies are generally not well studied.

3.2.1 Speckled Mousebird Colius striatus

Mousebirds, also known as colies (Coliiformes: Coliidae), are endemic to the Afrotropical region. Colius striatus has several races, with the subspecies kikuyuensis being restricted to the high rainfall areas of Kenya (Zimmerman, Turner & Pearson 1996) where it is endemic

(Bird Committee 2009). Mousebirds occupy forest edges and clearings, savannahs, abandoned cultivated areas, open woodlands, orchards and gardens (Yamagishi & Kabango

1986). They are primarily frugivores and herbivores (Keith, Urban & Fry 1992), live in small groups of 7-8 birds, roost communally in groups of ~20 birds (comprising of several families), and engage in mutual preening (Yamagishi & Kabango 1986; Keith, Urban & Fry

1992). They are cooperative breeders where helpers feed young at the nest and after fledging.

Sampling site elevations for this species in Nakuru ranged from 1857 m to 1913 m, whereas in Nyandarua sampling sites ranged from 2343-2576 m. Thus, there was a 430 meters 21 elevation difference between the lowest sampling point in Nyandarua and the highest sampling point in Nakuru.

Sexes in this species are similar. Zimmerman, Turner & Pearson (1996) and Fry, Keith &

Urban (1988) have provided a detailed description of various age categories. Adults have a brown crest that distinctively contrasts with whitish or silvery cheek (Plate 1). They also have bars on neck, throat and breast. The maxilla (upper bill) is black with a blue spot on culmen and the mandible (lower bill) is pinkish. Young birds (immatures and juveniles) have buff- edged feathers, short crest, bare blackish nape and a narrow pale stripe down centre of the back.

3.2.2 Red-capped Lark Calandrella cinerea

The Red-capped Lark (Passeriformes: Alaudidae) is a member of a diverse avian family with twenty-one species found in Kenya (Bird Committee 2009). The subspecies williamsi is endemic to Kenya and occurs in Naivasha, Nyandarua, Athi and Kapiti Plains south to

Amboseli (Zimmerman, Turner & Pearson 1996). Larks generally occupy short grass plains to bare ground. Red-capped Lark is granivorous and insectivorous and nests on the ground in pairs. However, after breeding they form large flocks. Sampling site elevations in Nakuru ranged from 1891 m to 2107 m and in Nyandarua, from 2336-2560 m. Thus, there was a 229 meters elevation difference between the lowest point in Nyandarua and the highest point in

Nakuru.

Zimmerman, Turner & Pearson (1996) provides a description of the differences between young and adult birds and between sexes. Rufous-chestnut crown feathers are a distinguishing feature between young ones and adults. Males generally have a deeper and 22 brighter rufous-chestnut crown than females (Plate 2). Juveniles have a dark crown with fine speckling, scaly back pattern and large blotches on the sides of the mottled breast.

Plate 1: Close-up photograph of an adult Speckled Mousebird (with the crest lowered).

Plate 2: An adult male of the Red-capped Lark. 23

3.3 Study design

3.3.1 Sample size (n) determination

Several strategies can be used to determine sample size including: (i) use of a census (for small populations), (ii) imitation of a sample size used for similar studies, (ii) using published tables, and (iv) applying formulas (Israel 1992). Sabuni et al. (2010), who studied the prevalence of ectoparasite on free-ranging chickens, used the formula strategy to determine sample size. The current study adopted the formula strategy computed as follows after Israel

(1992). n = z2pq e2

Where n = desired sample size (unknown);

z = normal deviation (i.e. standard value of 1.96 at 95% confidence level),

p = prevalence or the estimated proportion of attribute (ectoparasites) that is present in

the population.

q = 1 – p, and

e = the estimate (limits of error on the prevalence or the desired level of precision).

Since the desired confidence level was 95% (i.e. level of risk or α = 0.05), then z = 1.96.

Prevalence (p) was expected at 50% i.e. in every 100 birds of the same species examined, half of them were expected to be parasitized. Since p is at 0.5, then q = 1 – 0.5 = 0.5. At the proposal stage, the value of e (level of precision) was estimated at ± 8.25 percentage of the true value. The sample size (n) for this study was determined as follows:

Hence, n = 142 individuals for each study host species. The 142 individuals were spread between the study area such that a minimum of 71 birds had to be examined in Nyandarua and 71 in Nakuru. At the termination of data collection, the total number of hosts examined 24 and e for each host species was as follows: Red-capped Lark (n = 327, e = ± 0.055) and

Speckled Mousebird (n = 269, e = ± 0.0596). An increase from the initial target positively affected the level of precision (e) at which data was analysed, improving it from ± 8.25% to ±

5%. Hence, with α = 0.05, the results presented herein are highly reliable. In fact, Wilson et al. (2010) recommends that a large number of hosts be examined if there is a higher degree of variability in the numbers of parasites per host, for example as noted in Speckled Mousebird

(range 1 - 196), to obtain an accurate picture of parasite abundance in the host population.

3.3.2 Sampling design

Stratified and purposeful sampling design was used to divide the study areas into drier and wet habitats based on their distinct ecological characteristics. Nyandarua was thus described as high, wet and humid, while Nakuru was described as low, drier and semi-humid. Habitat was further broken-down to vegetated habitats including forests, woodlands/bushes, and grasslands based on known distribution and expected habitat use of Speckled Mousebird, which prefers vegetated areas, and Red-capped Lark, which prefers open grasslands with patches of bare ground.

3.3.3 Selection of sampling sites and study species

Selection of the sampling sites were split into two also depending on the niche (feeding guilds) occupied by each of the study species where Speckled Mousebird inhibit vegetated areas including forest edges and farmlands, while the Red-capped Lark live in grassland plains preferring patches of short grass and some bare ground. For each host species, sampling sites were then selected randomly depending on habitat of the species i.e. grassland plots in the case of Red-capped Lark and mapping territories for Speckled Mousebird using secondary data on their distribution (occurrence) from other ongoing ornithological research activities in both study areas. Sites chosen were at least 1.5 km to 2 km apart to ensure 25 independence of host populations. Secondary data for Speckled Mousebird colonies was available from an undergraduate student in Naivasha (Dominic Kimani) and local bird guides based in Njabini and Nyahururu who had up to date sightings and knew of feeding areas of the species. A doctoral student (Henry Ndithia) working on Red-capped Lark in Njabini and

Naivasha provided data on their distribution.

Additional searches in adjacent localities for the birds were carried out where previously reported birds were absent perhaps due to factors such as change in seasonal food availability

(both species are known to make local movements following changes in food availability) and unfavourable weather conditions especially heavy rains that resulted in flooded grasslands displacing grassland birds. This change in weather mostly affected Nyandarua

(Njabini), where search for Red-capped Lark populations was conducted since they were absent at the sites they had previously been recorded in sufficiently good numbers but were absent when sampling began. In Nyandarua, Red-capped Larks were trapped at one site in the south (Heni), two sites in the central parts (Murungaru) and five sites in the north. At the end of the day, specific areas where birds were captured for examination of lice was determined by habitat suitability and recent observations of target species.

3.3.4 Trapping and processing birds

Mist netting is one of the commonly used ornithological field technique to capture birds alive for study, and more so when birds need to be released afterwards. Bennun & Howell (2002),

Redfern & Clark (2001), Bibby, Jones & Marsden (1998) and Davis (1981) give an account of this technique. Fine mesh, four panel mist nets were erected using bamboo poles and guy ropes. Three to four, 12 and 18 meter long nets were joined and deployed using a rigorous design especially in open grasslands where there was no vegetation to conceal the nets. Red- 26 capped Larks are easy to trap with mist nets because they forage on the ground. Mist nets are a passive technique in which nothing is used to attract birds into nets. To enhance randomization of sampled individuals, birds were not driven (chased) to the nets. The schedule of operation required running the nets from 06:30hrs until 12:00hrs or earlier, and was never operated during rainy, drizzle or hot weather, as these are not recommended weather conditions. Trapping was usually done for a morning, and occasionally two, before moving to another site. Nets were frequently checked/controlled by one person while two or more others processed birds.

Captured birds were carefully removed from nets and immediately pacified in individual cotton cloth bags or direct into grocery papers to prevent loss of volant parasites, such as fleas and louse flies, and to keep parasites from transferring among hosts (Clayton & Walther

1997). Identification of birds at species level followed Zimmerman, Turner & Pearson (1996) while taxonomy followed Bird Committee (2009). To determine age of hosts species, plumage development patterns, colour of bare parts (eye, legs, and bill) and noticeable physiological processes such as breeding condition in adults (i.e. presence of a brood patch indicating breeding in adults) was used. Four age classes (after Jackson 2001) were used in this study.

From each individual, the following data was recorded: wing length (straight chord) using a wing ruler to the nearest mm, total head length (skull) and tarsus length using a veneer callipers (mm), live weight (g) using a pesola® spring balance, fat score and primary and secondary feathers moult scores.

To determine sex of birds, Whatman® FTA filter cards were used to preserve blood as a dry spot from which DNA was extracted and PCR conducted at the Pritzker Laboratory for 27

Molecular Systematics and Evolution, FMNH, Chicago. Owen (2011) gives a detailed account of collecting, processing and storing avian blood. In this study, blood was drawn with a 75mm long heparinized haematocrit-capillary tubes from the brachial/ulnar wing vein that was punctured using a 25g x ⅝” hypodermic needles. The needles were used only once

(and disposed) to avoid risk of infection of hosts and contamination of blood samples. To ensure that the DNA sexing protocol was working, sex of a few of the non-target species with sexual dimorphism e.g. Weavers and Sunbirds, were conducted whose results were positive.

DNA extractions were performed using the DNeasy Blood and Tissue Kit (Qiagen, Valencia,

CA, United States) following manufacturer’s protocols with minor modifications. A small cut-out (3x 6) mm of each dried blood spot preserved on Whatman® FTA cards was placed into individual wells of the extraction plate. Samples were incubated in the appropriate buffer for 2 hours at 560C and shaken at 400rpm. After the incubation period, the extractions were completed following instructions provided in the kit. DNA was eluted with a primary wash of

125µL of Buffer AE followed by a secondary wash of 75µL of Buffer AE. A random check to test the amount of DNA extracted (i.e. the nucleic acid concentration) showed a range of

89.1-116.4 ng/µL. The sex of each bird was determined through a PCR protocol targeting the

Chromo-helicase-DNA-binding (CHD) gene located on the avian sex (Z) chromosome of all birds as outlined by Griffiths et al. (1998).

For each PCR, one negative control was included per every 48 samples. PCR reactions included 3.0 µL of template DNA from the second elution, 2.5 µL of buffer, 2.5 µL of 8 mM

(millimolar) combined Deoxynucleotide Triphosphates (dNTPs), 1.0 µL each of 10 mM forward and reverse primers, 5 µL of bovine serum albumen, 1.0 µL of magnesium chloride,

1.5 µL of Taq polymerase, and 7.5 µL of double-distilled water for a total volume of 25 µL. 28

The thermocycler profile used follows the one in Griffiths et al. (1998) directly. 4.0 µL of each PCR product was run on a 2.5% agarose gel at 175 volts for 60-75 minutes. Images were taken of each gel and results were determined visually (eye).

Plate 3: PCR gel showing results for sex: two bands = female (♀); single band = male (♂).

Plate 3 above is a resultant PCR protocol showing partial results from a 96-well plate. The numbers (11-24, 35-48) refers to individual PCR products that correspond to known individual birds. The top row (numbers 11-24) indicate females (two bands), while numbers

38-43, and 46 are males (single band). Well number 48 is a negative control. Ultimately, 99% of screened samples were positively identified as either male or female. Where the results were not clear, a PCR gel was run again to ascertain the sex.

3.3.5 Lice sampling

3.3.5.1 Sampling technique 29

The methodological literature on collecting and quantifying different groups of avian ectoparasites for both voucher specimens and live birds is extensive for example, Fowler &

Cohen (1983), Wheeler & Threlfall (1986), Walther et al. (1995), Walther & Clayton (1997),

Clayton & Walther (1997), Visnak & Dumbacher (1999) and Clayton & Drown (2001). This study examined live birds for lice using dust-ruffling technique and visual examination. Birds were marked with a numbered metal ring for individual recognition to avoid repeat delousing, and were therefore examined only once during the study period. Although a few recaptures were encountered once or more times during visits at specific sampling sites, no parasite data obtained from these recaptures was included in the analysis.

Delousing hosts only once ensured that the observations (i.e. lice data) used in the analysis were independent, a fact also considered by Bittencourt & Rocha (2003). Aluminium metal rings were used in favour of plastic colour bands (or other marking techniques) because (i) the plastic rings are not usually numbered and so would be difficult to identify recaptured individuals bearing same ring colours or a combination; (ii) since each metal ring has a unique number and a return address, it is easy to report recaptures in future by other ringers thus yielding data on e.g. longevity, movements and population dynamics; (iii) some bird species with strong beaks like Mousebirds may easily smash the plastics soon after release and (iv) plastic bands fade with time. Metal rings have been used on birds for over 100 years and are largely known to have minimum effect on birds, if any, (Redfern & Clark 2001). 30

3.3.5.2 Procedure for dust-ruffling technique

This method uses an insecticidal powder that is readily available in most animal health care

(agrovet) product shops. One of the active ingredients in these insecticidal powder is permethrin. Although dead birds gives more accurate parasite estimates, killing birds for this purpose may have been considered by some people as undesirable on ethical grounds

(Clayton & Moore 1997), although sacrificing a few individuals is extremely important and valuable scientifically especially where the specimens are to be deposited in museum collections as a reference material. Dust-ruffling is hence the recommended technique when one is ringing birds and releasing them alive. The insecticidal powder was distributed throughout the plumage with fingers and birds were then placed in perforated grocery brown papers for c.10 minutes, after which the feathers were ruffled (stroked) using fingers for two minutes to dislodge dead or dying parasites over a collecting surface (melamine tray).

Adhering lice were examined visually by deflecting head and neck feathers with a pair of forceps. Dead or dying parasites in the grocery bag, used only once for each host individual, were recovered by emptying it on the tray. The bag was then opened up carefully to check for parasites in the folded parts. Where birds dropped faeces while in the bag, the faeces were stored in a tube containing analytical grade alcohol for observation under the microscope.

Identification of Phthiraptera was carried out at the FMNH, Chicago using Price et al. (2003) and the relevant taxonomic papers cited within.

3.3.6 Manipulation and analysis of data

Normality tests were done on abundance and intensity of lice data. Hammer, Harper & Ryan

(2001) and Razali & Wah (2011) recommend the use of the Shapiro-Wilk (W) test to assess whether the data are normally distributed. With the level of significance at α = 0.05, this test returned the following statistics: Red-capped Lark (Nyandarua: df (n) = 158, W = 0.2913; 31

Nakuru: df (n) = 169, W = 0.4168), and Speckled Mousebird (Nyandarua: df (n) = 123, W =

0.6196; Nakuru: df (n) = 146, W = 0.6276). Since all the values of W were lower than 1

(value of 1 being indicative of normal distribution), the louse data were therefore not normally distributed in the host populations. In an attempt to normalize the data, a value of

0.5 was added to all values to avoid zeros and allow log10-transformation as recommended by

Wilson et al. (2010). However, due to the high level of aggregation of parasites and presence of many zero values in the data (especially in Red-capped Lark), it was difficult to normalize them and therefore nonparametric statistics were used in data analysis.

Lice data was analysed using two statistical software packages. These were Quantitative

Parasitology (QPweb 3.0, Reiczigel, Rózsa & Reiczigel 2013), and Paleontological Statistics

(PAST version 2.7, Hammer et al. 2001). QPweb 3.0 is a free software package for use in education and science. Its statistical procedures are implemented using the statistical software

R, and is the recommended software for analysis of aggregated (right-skewed) parasite data

(Rózsa, Reiczigel & Majoros 2000) such as the data from this study. Among others, QPweb

3.0 was used to provide descriptive statistics of parasitic infestations for each of the two host species (including prevalence, mean intensity, median intensity etc.), exact confidence interval (CI) for the prevalence, Bootstrap CI for the mean intensity/abundance, aggregation indices (Poulin’s discrepancy index D) and to compare parasitic infestations between host species.

The Poulin’s discrepancy index D describes the level of aggregation of parasites. According to Wilson et al. (2010), this index quantifies aggregation as the discrepancy between the observed parasite distribution and the hypothetical distribution (generated by software) in which all hosts are used equally and all parasites are in sub-populations of the same size. The 32 index measures the relative departure of the observed distribution from a uniform distribution. Higher values (of close to 1) of Poulin’s D mean a greater aggregation.

PAST software was used to: (i) determine whether data were normally distributed and to fit a normal distribution curve to the histograms (ii) calculate various species diversity indices, and (iii) to calculate a Kruskal-Wallis statistic (nonparametric equivalent of one-way

ANOVA) and a Mann-Whitney U test (nonparametric equivalent of t-test for independent samples).

A Chi-square test was used to test the significance of association of intensity of lice between sex and age group. A Cramer's V coefficient, which is a measure of the strength of association among the variables, is also provided. This coefficient is not affected by sample size. It is interpreted as a measure of the relative strength of an association between two variables (sex and age) and ranges from zero to one (one being perfect association). The Chi- square is calculated using the following formula.

Since the intensity of lice was not normally distributed, a Kruskal-Wallis rank test was used to test for the significance of variation of lice intensity between the four different age groups of hosts. The procedure does not require that all data in each group (in this case the age groups) have equal numbers of valuables (McDonald 2009). The Kruskal–Wallis test, denoted as H, is computed as follows.

12 T 2 H   i  3(n 1)

n(n 1) ni

Where, H = Kruskal-Wallis test Statistic 33

n = total number of observations in all samples

ni = total number of values over the combined samples

Ti = rank sum for the ith sample i = 1, 2,…, k T2 = square of the sum of the ranks assigned to the jth sample

The Kruskal-Wallis test returns a statistic H whose distribution follows the chi-square distribution. The null hypothesis (Ho) is rejected if the calculated chi-square (H) is greater than or equal to tabulated value. Degrees of freedom is the number of groups (g, also denoted as k) minus one (df = g - 1).

A Mann-Whitney U test was used to test whether there was a statistically significant difference in the variation of louse intensity between the two study habitats (i.e. between the warmer, lower and drier Nakuru and the cooler, higher and sub-humid Nyandarua).

In calculating louse species diversity indices, the number of individuals of each louse genus

(both adult and nymphal stages) at each site was taken as the measure of abundance. A few indices were calculated to show different aspects of diversity in the louse communities. The most commonly used measure of heterogeneity of a community is Shannon’s Index (also called Shannon-Weiner Index), which is a measure of both the number of species and relative abundance of individuals of all species (Pielou 1974). This index, the most commonly used in ecology, assumes that all species are represented in a sample and that the sample was obtained randomly. It has values that range from 0 to 5, with 1.5 and 3.5 being the indices for real communities. The index is calculated as follows.

Where, ni = number of individuals or amount (e.g. lice) of each species N = total number of individuals (or amount) for the site, and 34

ln = the natural logarithm of the number.

Although generally more sensitive than Shannon-Weiner, the other commonly used diversity index is Simpson’s Diversity Index (1-D). It is a measure of diversity that takes into account the number of species present, as well as the relative abundance of each species. This index is often used to quantify the biodiversity of a habitat. It is computed as follows.

Where D is the Simpson’s Diversity Index, n the total number of individuals/organisms of a particular species, and N (population) is the total number of individuals for the study area or the community. The value of D ranges between zero (0) and one (1), with 1 representing a high (infinite) diversity and 0 representing no diversity.

Margalef Richness Index (d), which is also a measure of diversity in a community, was also calculated. It is computed as d = S-1/Log10N, where S is the number of species and N is the number of individuals. The higher the index, the greater the diversity detected.

To determine whether there was an association or relationship between lice abundance and body character (mass), a Spearman rank-order correlation was used. This non-parametric test measures the degree of association between two variables when data does not meet the assumptions of normality (McDonald 2009). It was used in this study to test the hypothesis that lice abundance does not affect body mass (live weight).

The data analysed and referred to herein is the total number of individual lice of different genera for each host. In this thesis, as indicated above, both the nymphal and the adult life 35 stages of lice collected from the four age categories of both host species are considered in the analysis. Rékási, Rózsa & Kiss (1997) also included the nymphs in the calculations to make results comparable with those of others. The analysis also puts together all the louse conspecifics recorded, and thus does not separate the individual genera in each host, for example in Speckled Mousebird, both Coliliperus sp. and Colimenopon sp. occurred on the same host and were considered as one population. 36

CHAPTER FOUR

RESULTS

4.1 Occurrence of host species and lice

4.1.1 Sample size and temporal distribution of examined hosts

During this study, 269 hosts of Speckled Mousebird (Nyandarua n = 123, Nakuru n = 146) and 327 hosts of Red-capped Lark (Nyandarua n = 158, Nakuru n = 169) were captured and quantitatively examined for lice between September and December 2012 (Table 4.1). A greater proportion of examined hosts were captured in October and November for both host species. A relatively few individuals (5%) of Red-capped Lark were caught in Nyandarua in

September due to flooding of most grassland fields and plots/farms where the species had been observed and plot earmarked for sampling. Due to this unexpected occurrence, sampling effort in December for Nakuru was reduced to minimize disparity in sample sizes between the study sites.

Table 4.1: Hosts trapped and quantitatively examined for lice in Nyandarua and Nakuru in each month during the study period.

Sampling Months (2012) Host Species Study Area Sample Sept. Oct. Nov. Dec. size (n) Nyandarua 16% 37% 30% 17% 123 Speckled Mousebird Nakuru 7% 54% 22% 17% 146

Nyandarua 5% 34% 39% 22% 158 Red-capped Lark Nakuru 15% 33% 49% 3% 169

Note Table 4.1: Each monthly percentage was calculated using the sample size for that study area e.g.

46 Speckled Mousebirds were caught in October in Nyandarua (whose total birds caught for the entire

46 period (n) = 123). Therefore, 46 in % will be: /123 x 100 = 37.4% (rounded off = 37%). To obtain (n)

for each month/study area: 0.37 x 123 = 46 individuals. 37

4.1.2 Sex and age composition of examined hosts

Adults accounted for 82% and 81% of Speckled Mousebird examined in Nyandarua and

Nakuru respectively. Sub-adults, immatures and juveniles comprised the rest of the host population. In Nyandarua, males accounted for 54% of the examined hosts compared to 57% in Nakuru. A few individuals (3%) of Speckled Mousebird were not sexed. This is because the blood supply to the brachial/ulnar vein in both wings was low and drawing blood using any of the other four techniques (i.e. jugular vein, toenail clip, metatarsal vein and cardiac puncture) as reviewed by Owen (2011) were unsuitable taking into account the associated disadvantages and risks vis-a-vis the bird’s welfare. In the case of Red-capped Lark, in addition to lack of a blood sample, the plumage characteristics were not developed to adequately determine the sex. Table 4.2 below shows the percentages of age and sex compositions of hosts examined during the study period.

Table 4.2: Age and sex compositions of examined hosts at both study areas.

Age groups Sex

Study Area Other Males Females Unknown Host Species Adults (sample size) ages (♂♂) (♀♀) Sex Nyandarua Speckled Mousebird 82% 18% 54% 46% - (n=123) Nakuru (n=146) 81% 19% 51% 40% 3% Nyandarua Red-capped Lark 68% 32% 51% 47% 1% (n=158) Nakuru (n=169) 60% 40% 50% 50% -

Note Table 4.2: The percentages were calculated using the sample size (n) for the study area for

example, 101 Speckled Mousebirds in Nyandarua were adults, with total birds caught for the entire

101 period (n) = 123. Therefore, 101 in % will be: /123 x 100 = 82%. To obtain (n) for each age group or

sex, multiply 0.82 x 123 = 101 Adults, and for sex, 0.54 x 123 = 66 males.

4.2 Distribution of lice among the hosts

Lice distribution in both host species showed an aggregated (right-skewed) pattern across the sampled host populations. Aggregation is a quantitative feature of macroparasites (parasitic helminthes and arthropods) that refers to a situation where most host individuals harbour low numbers of parasites and a few individuals playing host to many parasites (Wilson et al.

2010, Hatcher & Dunn 2011). The distribution of louse population was more aggregated in

Red-capped Lark (Poulin’s discrepancy index, D = 0.909) than in Speckled Mousebird (D =

0.571). This aggregation is also supported by the negative binomial exponent, k, (Speckled

Mousebird = 0.7669, Red-capped Lark = 0.0754). Figures 4.1 and 4.2, plotted using lice raw data (abundance), show distribution of lice on Speckled Mousebird and Red-capped Lark respectively.

)

t s

o 70

r 60

b m

u 50

(

c 40

u q

e 30

r F 20

0 0 20 40 60 80 100 120 140 160 180 Abundance (Number of Lice)

Figure 4.1: Distribution of lice on Speckled Mousebird.

280 260 240

220

)

s t

s 200

f 180

r e

b 160 m

u 140

(

c 120

e u

q 100

e r F 80 60 40 20 0 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 Abundance (Number of Lice)

Figure 4.2: Distribution of lice on Red-capped Lark.

Distribution of lice abundance was also plotted using log10-transformed data (Figures 4.3 and

4.4). A normal distribution curve is transposed to show expected normal distribution.

) s

t 35

o 30

b m

u 25

(

y c

n 20

e r

F 15

0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0 2.5 Abundance (Number of Lice per Host)

Figure 4.3: Distribution of lice on Speckled Mousebird with transposed normal curve. 40

270

240

)

s t

s 210

f o

180

b m

u 150

(

c 120

q e

r 90 F

0 -2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0 2.5 Abundance (Number of Lice per Host)

Figure 4.4: Distribution of lice on Red-capped Lark with transposed normal curve.

A normal probability plot showing distribution of lice on Red-capped Lark is shown in figure

4.5 that also helps to assess normality of data. Plotted points (filled triangles representing hosts) do not fit the predicted normal line with most of them lying away from it. The straight line in the figure shows the predicted line of perfect concordance.

In view of the fact that prevalence of lice was low in Red-capped Lark (17.1%) and that these parasites were over-dispersed in the examined host population, Rózsa, Reiczigel &

Majoros (2000) recommends also using a percentile (a measure of deviation) or a box-and- whisker plot to give more information about the distribution of the parasite on the host population. A percentile plot (Figure 4.6) is provided below which shows that the lice population was distributed in about 19% of the host population. 41

Figure 4.5: Normal probability plot for distribution of lice on Red-capped Lark.

Figure 4.6: Percentiles of distribution of lice on Red-capped Lark.

4.3 Prevalence and infestation intensities of lice

Speckled Mousebird had higher louse prevalence (Nyandarua 81.3%, Nakuru 96.6%, both habitats 89.6%) compared to Red-capped Lark (Nyandarua 13.3%, Nakuru 20.7%, both habitats 17.1%). Statistical comparisons on prevalence of lice infestation between Nakuru and Nyandarua for Red-capped Lark showed that there was no significant difference between the two habitats (Chi-square test p-value = 0.1025, Fisher’s exact test p-value = 0.0799, unconditional exact test p-value = 0.0786). A similar statistical test for Speckled Mousebird showed that the prevalence in the two habitats, Nyandarua and Nakuru, were however significantly different (Chi-square test p-value 0.0001, Fisher’s exact test p-value <0.0001, unconditional exact test p-value < 0.0001). Prevalence between the two host species (Red- capped Lark and Speckled Mousebird) indicates a statistically significant difference between them (Chi-square test p-value = 0.0001, Fisher’s exact test p-value < 0.0001, unconditional exact test p-value < 0.0001). These results reveals that the behaviour of a species (for example the social Speckled Mousebird and the more or less solitary Red-capped Lark) is important than habitat in determining prevalence.

Table 4.3 provides descriptive statistics of infestation: sample size, infested hosts, prevalence, mean intensity, median intensity, confidence limits and mean abundance for each host species. In both hosts, prevalence of lice was higher in the lower, drier and warmer Nakuru compared to the higher, wet and cold Nyandarua. Speckled Mousebird had a higher prevalence of lice than Red-capped Lark. The mean intensity and abundance also differed between the host species. Due to the high prevalence in Speckled Mousebird, the mean intensity was almost equal to the mean abundance. The mean abundance for both host species and at each site falls within the range of Bootstrap confidence limits. 43

Table 4.3: Descriptive statistics for lice infesting Speckled Mousebird and Red-capped Lark in Nyandarua and Nakuru Counties of Kenya.

Median Actual Mean Study Sample Infested Prevalence Mean Bootstrap CL Host Species Intensity (exact) CL Abundance Area Size (n) Hosts (%) Intensity for MA (MI) for MI (%) (MA) Nyandarua 123 100 81.3 18.2 10.0 95.4 14.7 11.5 – 20.0 Speckled Mousebird Colius striatus Nakuru 146 141 96.6 19.74 14.0 95.4 19.1 16.1 – 24.0 kikuyuensis Both areas 269 241 89.6 19.32 12.0 95.2 17.3 15.0 - 20.8

Nyandarua 158 21 13.3 4.24 2.0 96.1 0.563 0.304 – 1.05 Red-capped Lark Nakuru 169 35 20.7 5.51 4.0 95.5 1.14 0.746 – 1.78 Calandrella cinerea williamsi Both areas 327 56 17.1 5.04 3.0 95.9 0.862 0.606 – 1.22

Bootstrap Confidence Limits (CL) for both Median Intensity (MI) and Mean Abundance (MA) is by the Bootstrap (BCa) method with 2000 bootstrap replications. The

confidence level is at 95% (i.e. α = 0.05). 44

4.4 Louse species composition

In this section, images of the louse genera recorded on each host species are shown with a brief discussion. The images (enlarged) were taken using an Olympus SZX-12 dissecting microscope with a zoom magnification of 7x-9x. Images were taken after mounting the lice on slides using the Canada Balsam Technique as described in details by Palma (1978).

4.4.1 Lice found on Speckled Mousebird

Two genera of lice Colilipeurus sp. (Ischnocera: Philopteridae) and Colimenopon sp.

(Amblycera: Menoponidae) were recorded on Speckled Mousebird in both habitats (Plate 4).

Plate 4: Photographs showing lice genera found on Speckled Mousebird. A: Colilipeurus sp.

(♀); B: Colimenopon sp. (♂).

Table 4.4 provides descriptive statistics of the two louse genera, whereas table 4.5 gives summary descriptive statistics of infestation on Speckled Mousebird in both habitats.

Colilipeurus sp. was the most common genera (high prevalence) and was more prevalent in

Nakuru (92.5%) than in Nyandarua (80.5%). Infestation rates and patterns differed between habitats and the two louse genera. Of the infested hosts (n = 241), 20.3% had a single 45

infestation by Colilipeurus sp. compared to a 12.6% by Colimenopon sp. The rest of the hosts

(67.1%) had a multiple infestation i.e. had both louse genera on them.

Table 4.4: Descriptive statistics of the two louse genera found on Speckled Mousebird.

Colilipeurus sp. Colimenopon sp.

Mean 16.97 4.30 Standard Error 1.55 0.31 Median 10.00 3.00 Mode 3.00 1.00 Standard Deviation 23.68 4.00 Sample Variance 560.87 16 Range 195 31 Minimum 1 1 Maximum 196 32 Sum (Population) 3,970 701 Count 234 163

Table 4.5: Comparison of infestations of the louse genera found on Speckled Mousebird.

No. No. Prevalence Mean Median Poulin’s Habitat Hosts Infested Louse genera (%) Intensity Intensity D (n) Hosts

Nakuru 146 135 92.5 17.53 11 0.561 Colilipeurus sp. Nyandarua 123 99 80.5 16.19 9 0.647

Nakuru 146 114 78.1 4.18 3 0.519 Colimenopon sp. Nyandarua 123 49 39.8 4.59 3 0.802

Although both chewing louse genera were found on the same host individual in most cases,

Colilipeurus sp. accounted for the largest proportion of the overall louse population (Figure

4.7). The nymphal stages accounted for the largest population in both louse genera indicating 46

that the louse were breeding. The Poulin’s discrepancy index, D, values indicates that distribution of both louse genera in each habitat type was highly aggregated especially in

Colimenopon sp. in Nyandarua where the D value (0.802) is very close to 1.

Figure 4.7: Population of the two lice genera found on Speckled Mousebird, indicating dominance of Colilipeurus sp. over Colimenopon sp.

4.4.2 Lice found on Red-capped Lark

Three genera of lice in varying proportions of very low abundance and prevalence were recorded on Red-capped Lark. These were Menacanthus sp. (Amblycera: Menoponidae),

Philopterus sp. (Ischnocera: Philopteridae) and Ricinus sp. (Amblycera: Ricinidae) (Plate 5).

Plate 5: Photographs showing lice genera found on Red-capped Lark. A: Menacanthus sp.

(♀); B: Philopterus sp. (♀); C: Ricinus sp. (♀).

Table 4.6 below gives a summary of descriptive statistics on infestation on Red-capped Lark.

Among the louse genera, Menacanthus sp. had the highest prevalence (8.6 %) followed by

Philopterus sp. (5.5%) and then Ricinus sp. (4%). In terms of single louse genera infestation in the infested host population (n = 56), Menacanthus sp. accounted for 37.5%, Philopterus sp. 25% and Ricinus sp. 21.4%. The three louse genera were however not found to occur together on a single host. Incidences of two louse genera infesting the same host (multiple infestations) were very few where Menacanthus sp. was recorded twice interacting with

Philopterus sp., and twice with Ricinus sp. while Philopterus sp. and Ricinus sp. were recorded on the same host only once. 48

Table 4.6: Descriptive statistics of the louse genera found on Red-capped Lark.

Menacanthus Philopterus Ricinus sp. sp. sp. Mean 5.64 3.06 4.00 Standard Error 0.94 0.68 1.12 Median 4 2 2 Mode 1 1 1 Standard Deviation 5.00 2.88 4.34 Sample Variance 24.98 8.29 18.86 Range 19 11 15 Minimum 1 1 1 Maximum 20 12 16 Sum (Population) 158 55 60 Count 28 18 15

Table 4.7: Comparison of infestations of the two louse genera found on Red-capped Lark.

Number Host of Infested Prevalence Mean Median Louse genera Sample Size (n) Hosts (%) Intensity Intensity

Menacanthus sp. 327 28 8.6 5.64 4.0

Philopterus sp. 327 18 5.5 3.06 2.0

Ricinus sp. 327 15 4.6 4.00 2.0

Figure 4.8 below shows the distribution of the three genera of lice on Red-capped Lark. In terms of numbers (i.e. population size), Menacanthus sp. dominated over both Philopterus sp. and Ricinus sp.

Figure 4.8: Population of the three genera of lice found on Red-capped Lark, indicating dominance of Menacanthus sp.

4.4.3 Other ectoparasites recorded on the two host species

Apart from lice (Insecta: Phthiraptera), the only other group of ectoparasite recorded were feather mites (Arachinida: Acari). Compared to lice in each hosts species, it appears that feather mites occurred in low prevalence (Speckled Mousebird: Nyandarua 42.3%, Nakuru

26%; Red-capped Lark: Nyandarua 3.8%, Nakuru 2.4%). It is interesting to note that unlike in lice, prevalence in mites was higher in Nyandarua than in Nakuru.

4.5 Lice species diversity

Table 4.8 shows the three diversity indices used to describe the diversity of louse communities in both host species. Although lice were identified up to genus level, the indices calculation considers them as individual species since they are morphologically different. 50

The three indices show that the louse communities in both sites are of low diversity. For example, the values for Simpson’s Diversity Index whose values ranges between 0 – 1, indicate that lice species diversity in Red-capped Lark can be described as of medium diversity (D = 0.576) while that of Speckled Mousebird as of low diversity (D = 0.256).

Results for Shannon-Weiner Index, H’, show that neither of the host’s lice species exhibits a real community (Speckled Mousebird H’ = 0.637; Red-capped Lark H’ = 0.97). This is because, H’ values for a real community ranges from 1.5 to 3.5. The results for Margalef’s

Richness Index, d, also shows a low diversity of lice species. This index can have values bigger than 1 that would indicate great species diversity.

Table 4.8: Diversity indices of the louse genera found on Red-capped Lark and Speckled

Mousebird.

Speckled Mousebird Red-capped Lark Both Both Nyandarua Nakuru Nyandarua Nakuru Habitats Habitats Simpson’s Diversity Index, D 0.2156 0.279 0.256 0.531 0.462 0.576

Shannon Index, H’ 0.373 0.452 0.637 0.849 0.764 0.970

Margalef Richness Index, d 0.133 0.126 0.119 0.446 0.384 0.357

4.6 Variation of lice intensity between host species age groups

Four age groups, determined using colour of bare parts (eyes, bill and tarsus) and plumage characteristics, were considered in this study. These were adult, sub-adult, immature and juvenile. These categories do not refer to a specific age in terms of days or years but rather refer to a development stage as depicted by plumage and bare parts characteristics.

4.6.1 Variation in intensity of lice between age groups in Speckled Mousebird

In this section, as well as in section 4.6.2, only the infested individuals (intensity) were considered in the analysis. Table 4.9 provides descriptive statistics for lice in each age group including mean lice, Standard Error (SE), Standard Deviation (SD )and sample size (n).

Table 4.9: Summary descriptive statistics for lice on the four age groups of Speckled

Mousebird.

Adults Sub- Immatures Juveniles Adults Mean 16.73 35.12 27.27 25.71 SE ±1.68 ±9.47 ±6.35 ±4.45 Median 10 20 20 19 Mode 3 15 20 17 SD 23.30 39.04 24.60 18.36 Variance 542.88 1,523.86 605.21 337.22 Range 195 155 80 72 Minimum 1 6 2 5 Maximum 196 161 82 77 Sum (#Lice) 3,212 597 409 437 Count (n) 192 17 15 17

The overall variation of intensity of lice was significantly different between various paired host age groups (Hχ² = 21.72, Hc = 21.75, df = 3, p-value <0.0000). In table 4.10, significant differences of louse infestation is however only obtained when adults were compared to: sub- adults, immatures and juveniles; between sub-adults and adults; and between juveniles and adults. This is because a relatively high number of adults (81%, n = 192) were infested compared to all the other three age groups put together (19%, n = 49). In the table, zero values, for example adults vs. adults, indicate no comparison within the age group while bolded text indicates a significant difference of louse intensity between paired age groups. 52

Table 4.10: Mann-Whitney pairwise comparisons matrix of variation of louse intensity between the four age groups of Speckled Mousebird.

Adults Sub-adults Immatures Juveniles Adults 0 0.0014 0.0319 0.0014 Sub-adults 0.0083 0 0.5966 0.8362 Immatures 0.1914 1 0 0.9397 Juveniles 0.0082 1 1 0

In figures 4.9 and 4.10 below, the inner whisker bars indicates the Standard Error (SE) whereas the outer bars indicate Standard Deviation (SD) at 95% confidence interval. The SE whisker bars are close to each other in the adults indicating a small SE due to their large sample size. A small sample size results to a larger SE as observed in other age groups especially the sub-adults.

Figure 4.9: Variation in louse intensity in the four age groups of Speckled Mousebird.

4.6.2 Variations in intensity of lice between age groups in Red-capped Lark.

There was a statistically significant difference in the variation of louse intensity in all the four age groups of Red-capped Lark (Hχ² = 10.05, Hc = 10.26, df = 3, p-value = 0.0165). This difference was only observed between adults and immatures, and between adults and juveniles (shown by bolded text in table 4.12).

Table 4.11: Summary descriptive statistics for lice on the four age groups of Red-capped

Lark.

Adults Sub-Adults Immatures Juveniles

Mean 4.26 4.2 6.78 11.33 SE ±0.74 ±1.41 ±1.61 ±4.67 Median 2 2.5 5 10 Mode 1 2 5 #N/A SD 4.32 4.47 4.82 8.08 Variance 18.62 19.96 23.19 65.33 Range 17 15 15 16 Minimum 1 1 1 4 Maximum 18 16 16 20 Sum (#Lice) 145 42 61 34 Count (n) 34 10 9 3

Table 4.12: Mann-Whitney pairwise comparisons of variation of lice intensity between the four age groups of Red-capped Lark.

Adults Sub-adults Immatures Juveniles Adults 0 0.529 0.023 0.014

Sub-adults 1 0 0.128 0.088

Immatures 0.135 0.077 0 0.321

Juveniles 0.081 0.528 1 0 54

Juvenile hosts had the highest louse mean intensity than the other three age categories.

Figure 4.10 below shows the mean louse intensities for the four age categories. Juveniles had the greatest SE as well as SD because of the few number hosts infested/examined.

Figure 4.10: Variation in louse intensity in the four age groups of Red-capped Lark.

4.7 Variation in louse intensity between habitats and host species sexes

4.7.1 Intensity of lice between habitats

Mann-Whitney U tests showed that a highly significant difference in louse intensity (at p ≤

0.05) existed between the two study areas (i.e. Nakuru and Nyandarua) only in Speckled

Mousebird (Nakuru: n = 141, mean rank = 75.45; U = 5929, z = -2.104, p(same) = 0.354;

Nyandarua: n = 100, mean rank = 45.55, Monte Carlo p = 0.036) and not in Red-capped Lark

(Nakuru n = 35, mean rank = 19.21, U = 289.5, z = -1.328, p(same) = 0.1842; Nyandarua n =

21, mean rank = 9.295, Monte Carlo p = 0.184). 55

4.7.2 Variation of louse intensity between host sexes

Distribution of lice between males and females (as independent variables) was not significant at p ≤ 0.05 between the sexes in both host species (Speckled Mousebird: males (n = 132, mean rank = 63.3, females n = 106, mean rank = 56.2, U = 6288, p (two-tailed) = 0.179; Red- capped Lark: males n = 27, mean rank = 12.74, females n = 29, mean rank = 15.76, U =

335.5, p (two-tailed) = 0.357).

4.7.3 Association of intensity of lice between sexes and age groups

Chi-square was used to test for the strength of association of louse intensity between host’s sexes and age groups. The following results were obtained for this test. Speckled Mousebird:

χ²0.05, 3 = 95.101, Monte Carlo p = 0.0001; and Red-capped Lark: χ²0.05, 3 = 57.34, Monte

Carlo p = 0.0001. The results thus show that there was a relationship (or association) in the distribution of lice between host’s age and sex. Cramer’s V coefficient was used to test for the strength of this association. None of the host species had a perfect association i.e. was weak in Speckled Mousebird (Cramer’s V = 0.143), and moderate in Red-capped Lark

(Cramer’s V = 0.399). The Cramer’s Coefficient (V) ranges from zero to one, with one being a perfect association.

4.8 Relationship between adult host’s body mass and louse abundance

In this test, adults of both host species were considered in the analysis. This is because the other three age groups (sub-adults, immatures and juveniles) were jointly fewer in number compared to the adults (Speckled Mousebird: adults n = 219, others n = 50; Red-capped

Lark: adults n = 209, others n = 116) in addition to their mean mass being less than that of the adults (Speckled Mousebird: adults = 54.2g, others = 45.1g; Red-capped Lark: adults = 56

23.6g, others = 21.9g). Spearman’s rank order correlation was used to analyse this relationship.

4.8.1 Relationship in Speckled Mousebird

The results showed that there was no relationship between body mass and louse abundance

(Spearman’s rho = -0.049, df = 217, p-value = 0.475). When adults with lice (intensity) are considered only in the analysis, the results obtained are: rho = •0.021, df = 190 and p-value =

0.7769. In both cases (abundance and intensity), the results are not statistically significant.

This relationship is illustrated in figure 4.11. Adult hosts in Nyandarua had a slightly higher mean body mass (55.5g, n = 118) compared to those in Nakuru (53.1g, n = 101).

4.8.2 Relationship in Red-capped Lark

The relationship in Red-capped Lark also indicated a non-statistically significant relationship between body mass and louse abundance (Spearman’s rho = -0.035, df = 207, p-value =

0.61). The results obtained with adult’s lice intensity are: Spearman’s rho = •0.0247, df = 32, p = 0.1583. Figure 4.12 graphically illustrates this relationship. Like in Speckled Mousebird, adult Red-capped Lark were slightly heavier in Nyandarua (24.8g, n = 108) than in Nakuru

(23.4g, n = 101). 57

Figure 4.11: Relationship between adult’s host body mass and louse abundance in Speckled Mousebird.

Figure 4.12: Relationship between adult’s host body mass and louse abundance in Red- capped Lark. 58

In both hosts, the results show that the relationship between adults body mass and louse abundance (as well as intensity) is weak i.e. an increase in one variable does not significantly affect the other variable. The increase or decrease is insignificant. This means that heavier adult hosts do not necessarily mean they will have fewer numbers of lice, and lighter adult hosts having more lice. This is further supported by negative values of Spearman’s rank correlation coefficient (•0.49 and •0.35) that are close to 0, where 0 means that the two variables does not vary at all. The p-values in both host species (0.61 & 0.16) therefore mean that there is no evidence to believe that mass is correlated to the number of lice. In both hosts, the trend lines (that lie almost adjacent to the mean mass), are more or less horizontal thus further disclosing no correlation between the two variables (Figures 4.11 and 4.12). 59

CHAPTER FIVE

DISCUSSION

5.1 Distribution, prevalence and diversity of lice species in the two hosts

A relatively large sample size of hosts was realised in this study to test the study hypotheses and to provide results with reasonable confidence. Collecting ectoparasites within a relatively short period (like in this study) minimizes errors since parasites have their own biology and populations that can vary rapidly in both space and time (Clayton & Moore 1997). Although the minimum sample required to assess mean sub-populations (may) have never been published for avian lice (Rékási, Rózsa & Kiss 1997), the minimum sample size requirements for a ± 50% precision for this study were met for both host species (initial target was at ±8.25%). In fact, Clayton & Moore (1997) recommends that quantifying parasites should be made from a large sample of hosts as much as possible because estimates from small numbers of hosts can be misleading. The results presented here are therefore a true representation of the populations from which the samples were obtained. More or less balanced sample sizes were maintained for each host species at each study area making the results comparable. In fact, host sample size is a factor known to influence some of the parasite measures (Rékási, Rózsa & Kiss 1997).

Two and three louse genera were collected from Colius striatus kikuyuensis and Calandrella cinerea williamsi respectively. The two host species did not share louse genera but did share sub-orders (Ischnocera and Amblycera) and two families (Philopteridae and Menoponidae).

One family, Ricinidae, was exclusively recorded on Calandrella cinerea williamsi. However, these families and genera are common at both study areas for both host species. Ledger

(1980) and Price et al. (2003) lists two species of lice from Colius striatus i.e. Colilipeurus radiatus and Colimenopon hamatum. However, while Price et al. (2003) lists two louse 60

species from Calandrella cinerea (i.e. Brueelia calandrella and Ricinus serratus), Ledger

(1980) lists no louse from this host. It therefore follows that, Menacanthus sp. and Philopterus sp. are new host records for Red-capped Lark bringing her known genus/species of lice to four. Ironically, Menacanthus was found to be the most common louse genus on this host species showing that not much is known about lice of this host and indeed of many other Kenyan wild bird species. According to Palma, Price & Hellenthal

(1998), the genus Menacanthus has many species, is cosmopolitan and its host specificity is very low. Dik et al. (2011) also recorded a new host record for this genus in Turkey. The genus Philopterus (ex. Calandrella cinerea williamsi) was the rarest of the three recorded louse genera and seems more prevalent in the lower, drier and warmer Nakuru (Naivasha) region since it was only recorded in three (3) hosts in the higher, sub-humid and colder

Nyandarua compared to 15 hosts in Nakuru. The sub-population of Red-capped Lark captured and examined in Nyandarua at Heni (located at the edge of the Rift Valley where both habitats overlap) were mist-netted towards the end of the study period when they showed up since start of the study. This suggests that there is a possibility of Red-capped

Lark not only moving locally within sites in Nyandarua (Heni) but also between the habitats.

Distribution of lice among hosts that were examined was strongly over-dispersed

(aggregated) as is typical of most macroparasites (Johnson et al. 2003). This aggregation however differed between the two host species, and even between the lice genera themselves.

For example, Ischnocera exhibited higher intensity infestations than Amblycera in Speckled

Mousebird. One possible explanation of this difference in intensity of infestation between

Ischnocera and Amblycera is that perhaps the host’s immune response is affecting the

Amblycerans who occur in contact with host skin, feeding on host skin and chew emerging tips of developing feathers to obtain blood more than it (immune response) affects the

Ischnocerans that live on feathers and feed on the non-living keratin of feather barbules 61

(Møller & Rózsa 2005). The high number of Colilipeurus could therefore be correlated to the host’s active moulting of primary flight feathers (mean score = 14.45, n = 219) noted throughout the study period. Although Speckled Mousebird occupy harsh habitats that would wear the feathers, lice too (especially if present in big numbers) damage feathers by chewing on them (Clayton & Moore 1997) and this can affect hosts in several ways such as diversion of energy for example from breeding to moulting to replace worn out feathers since efficiency in flight is essential for safety, movement, breeding and foraging.

Parasites typically show an aggregated frequency distribution among individual hosts in a host population (Clayton & Moore 1997). This contagious or clumped distribution pattern is important since their transmission (especially that of lice) is highly dependent on direct body- to-body contacts among hosts (Rékási, Rózsa & Kiss 1997). As observed in this study, the level of aggregation differs significantly between hosts where it varies in the probability of active vertical transmission. For example, the nearly solitary Red-capped Lark has a higher louse aggregation than the more social Speckled Mousebird, which is potentially due to lower probability of active vertical (within species) transmission.

A significant difference in louse prevalence was noted between the non-passerine Speckled

Mousebird and the passerine Red-capped Lark, and between the habitats, i.e. between the drier, lower and warmer Nakuru, and the wet, higher and cooler Nyandarua. These findings are similar to Dik et al. (2011) who found out that infestation rates in passerines was four times lower than that of non-passerines (waders), and attributed this to the large body size and gregariousness of the waders. Using data collected during this study, this argument of size differences is applicable in the two hosts since Speckled Mousebird (mean mass: ♂♂ =

51.9g, n = 149; ♀♀ = 53.4g, n = 117) is more than twice the size of Red-capped Lark (mean mass: ♂♂ = 24.2g, n = 165; ♀♀ = 23.0g, n = 158), thus large birds/hosts provide a large 62

living surface area for ectoparasites. These findings seem to differ with Moyer et al. (2002a) who experimentally showed that birds in arid regions have fewer ectoparasitic lice than birds in humid regions. The reason for this difference in observations could be that the margins in differences between the current study habitats and the conditions under which Moyer et al.

(2002a) conducted their study may not be as distinct i.e. differences in environmental variables between Nyandarua and Nakuru are perhaps minimal to influence huge differences.

Another potential reason for differences in infestation rates between the study host species is their social behaviour. Speckled Mousebird lives in family groups of 3-15 birds (Fry, Keith

& Urban 1988). They also congregate and roost clustered together, with each roost comprising several families. During the day, they often feed, preen and play with each other.

This host species is also a communal and cooperative breeder, where the breeding pair receives help from closely related or other individuals in the group to raise young. All these social behaviours increase opportunities for body-to-body contact. Besides bonding groups and helping in temperature maintenance (Fry, Keith & Urban 1988), this social behaviour also increases opportunities for vertical (within species) transmission of ectoparasites from one individual to the other. Unlike Speckled Mousebirds, Red-capped Larks are not social and thus have limited vertical transmission of lice during the breeding season (for example while mating) and from adults to nestlings. Outside the breeding season and during migration, Red-capped Lark becomes highly gregarious (Fry, Keith & Urban 1988). Since avian lice are a contagious species, whose transmission largely depends on direct body-to- body contacts (Rékási, Rózsa & Kiss 1997), there are thus likely reduced chances of louse transmission between individual Red-capped Larks due to limited opportunities for body-to- body contact between them. Host sociality is indeed known to affect host-parasite interactions by increasing level of ectoparasitism and thus may be a cost of social life

(Rékási, Rózsa & Kiss 1997). Social bird species such as Speckled Mousebird are hence 63

likely to be associated with high prevalence and less aggregation (i.e. lower values of

Poulin’s discrepancy index, D) of the ectoparasites as observed in this study. Thus D values in this study correlates with the host’s social system.

Species diversity refers to the number and relative abundance of different types of species

(organisms) present in an area or any other specified region (Starr, Evers & Starr 2008).

Three indices: Shannon-Weiner Index, Simpson’s Diversity Index and Margalef Richness

Index, were calculated to describe the diversity of the louse genera recorded in the two hosts.

None of the two host’s Shannon Index (H’) indicates that the lice form a real community (i.e. one that falls within range of 1.5 to 3.5). This means that both Nyandarua and Nakuru communities of louse genera (species) are not particularly diverse. The Margalef Richness

Index (d) on the other hand reveals a great similarity of the lice communities for both host species and habitats since the obtained ‘d’ values are more or less the same for each host species and habitats. Simpson's Diversity Index showed that the lice communities in both hosts are less diverse.

The findings of this study show a clear difference in the level of louse population’s inequality. This difference in populations of lice could be due to interacting factors such as competition between and within louse genera/species, influence of abiotic factors (like temperature and humidity), food availability and its quantity and quality, and delousing behaviour of host e.g. preening, dust-bathing etc., and breeding status and sociality of host.

5.2 Comparison of intensity of lice between host species, age groups and sex

In both host species, adults formed the largest proportion of examined individuals than the other age groups, especially in Speckled Mousebird. A possible explanation for this high proportion of adults in Speckled Mousebirds could be that young birds take a shorter time to 64

mature into adult plumage than do young Red-capped Larks or sampling happened long after the breeding season. Louse distribution and intensity was not significantly different between host sexes. The sex ratios of both host species were nearly 1:1, and this may therefore mean that lice have no preferred sex for a host. It further suggests that the data was collected from randomly selected individuals, and that in nature, sexes of wild birds is evenly distributed.

Although there was no significant difference in lice infestation between sexes, this might not be the case in bird species that are polygamous, both polygynous (a male mating with more than one female) and polyandry (a female mating with more than one male). The distribution of lice among the four host age groups was statistically significant for both host species.

Associations between age groups show that young birds (juveniles and immatures) carry the highest mean intensities (greatest burden) of the louse population. The possible explanation of this observation could be that lice might be synchronising their breeding with that of their hosts as an opportunity for dispersal. The mean number of lice nymphs observed supports this argument of synchronized breeding since young birds had higher nymph mean values than adults. It is also possible that young birds, especially juveniles, are not only fully dependent on adults for food but also for preening and delousing. Juveniles may also not be dust-bathing leading to higher parasitic loads.

In addition to age and sex of host, there are possibly other factors operating and contributing to this great variation in intensity of lice at both study sites and host species. Such factors include body/health condition of the host, weather, season, species of lice involved and their general ecology, for example how they interact among themselves and with other ectoparasite groups present.

5.3 Intensity of lice between habitats

Habitat appears to be less important than other factors in determining prevalence, at least as observed in this study; where prevalence seems to depend on host species more than the habitat. Habitat was statistically significant for determining prevalence of chewing lice only in Speckled Mousebird but not in Red-capped Lark. However, other researchers have found that weather conditions such as rainfall, ambient temperatures, and humidity have effects on intensity and prevalence patterns of ectoparasites (Clayton, Adams & Bush 2008). Merino &

Potti (1996) found out that not only did weather affect the growth and survival of nestlings of

Pied Flycatchers (Ficedula hypoleuca) but also influenced the patterns of intensity and prevalence of ectoparasites. However, such conclusions and observations may require longer- term studies. Past studies have shown that prevalence is too variable because it depends on the transmission of parasites among hosts and is sensitive to variable environmental conditions that commonly change between years (Poulin 2006 cited in Santiago-Alarcon

2008).

5.4 Relationship between adult host’s body mass and louse abundance

The relationship observed between louse abundance (as well as intensity) and adult host body mass is a weak relationship. The possible explanation hence would be that change in both body mass and number of lice are influenced by other factors and that both variables (lice and mass) don’t really correlate at all. Such a relationship would therefore only be observed by chance and not by random sampling. The large p-values obtained means that the correlation is not real. However, it is hard to know whether any seasonal variation in weight would be due to seasonality in food (its quality and quantity), louse intensity or other factors.

For example, when all age groups (adults, sub-adults, immatures and juveniles) are included in the analysis, the results indicates a statistically significant though weak relationship which means age of host is possibly one of the factors that affects this relationship. Comparing mass 66

between the two habitats shows that birds in Nyandarua are slightly heavier than those in

Nakuru meaning that habitat too is an important factor in the lice abundance-body mass relationship as it provides many critical opportunities such as source of food. As seen earlier, prevalence too differed significantly between the two study areas (habitats) and hosts, further supporting the observation that other factors are involved in influencing parasitic load and host body mass. Another key observation in this study was that a few of the heavily infested individuals were of above average body mass compared to some individuals with no infestation yet were below average body mass.

While studying the ectoparasites of the Western Fence Lizards (Sceloporus Occidentalis) in

California, Lumbad, Vredevoe & Taylor (2011) concluded that the intensities of ectoparasites were affected by both season and sex of the host. Differences in mass between habitats and within a given habitat may also vary greatly and could be a factor of availability, distribution, quantity and quality of food. Parasites, such as lice, have profound effects on their hosts. Møller & Rózsa (2005) sums up the potential effects of lice on avian life history includes influence on flight performance, metabolism, life expectancy, and sexual selection.

CHAPTER SIX

CONCLUSION AND RECOMMENDATIONS

6.1 Conclusion

Some good and reliable results were obtained for each of the study objectives. In objective 1

(a survey of lice associated with Speckled Mousebird Colius striatus kikuyuensis and Red- capped Lark Calandrella cinerea williamsi), two and three genera of lice were recorded respectively. In the Red-capped Lark, two of the louse genera, Philopterus sp. and

Menacanthus sp., were recorded for the first time on this host bringing to four her known lice genera. This supports the need for continued avian lice research in Kenya. In terms of louse prevalence, Speckled Mousebird (a social species) was observed to have higher prevalence than Red-capped Lark (a more or less solitary species), and hosts in the drier, sub-humid to semi-arid Nakuru had more lice than those in the wet, humid to dry sub-humid Nyandarua.

Large sample sizes of nearly or more than twice the minimum target required for statistical tests in this study for each host species was achieved. A larger sample size resulted to a high level of precision i.e. the results presented are an accurate picture of distribution of the parasites (lice) in the host population. Although a prevalence of 50% had been arbitrary estimated for this study, higher estimates are recommended or could be adopted in future studies especially for social species or those that live in groups (such as flocks, herds, packs, colonies, clans, prides etc.) and on expected trapping success of the host species.

Study objective two, which was to determine whether intensity of lice infestation is affected by sex and age of host, was also achieved greatly. The null hypothesis that intensity of lice does not vary with age and sex of host was rejected for age and accepted for sex. The results of this study show that intensity of lice is affected by age of host. Perhaps young birds 68

(juveniles and immatures) had not yet been exposed to many conspecifics (other than their parents and/or helpers while at the nest) soon after they leave nest and thus there had not been sufficient opportunity for lice transmission since these wingless parasites (lice) largely rely on body-to-body contact for dispersal. The intensity of lice did not vary with sex of host.

In contrast, Potti & Merino (1995) observed that both the number of lice (intensity) and the prevalence of louse infestation were significantly higher in females than in males of Pied

Flycatchers, meaning that infestation is perhaps not only affected by sex of host but also by the ecological niche and sexual behaviour of the host species under study.

The third objective of this study was to determine whether intensity of lice varied between the two habitats i.e. between the wet, cooler and humid Nyandarua and the drier, warmer and semi-humid Nakuru. The null hypothesis for this objective that intensity and prevalence of lice does not vary with study area (habitat) was rejected, and the alternative hypothesis that there is indeed variation in prevalence and intensity of lice in the habitats studied accepted.

Given the variation between the study areas in terms of environmental variables such as relative humidity, temperature, precipitation and elevation, such differences in prevalence are expected. One explanation for this observation could be that birds in the higher, cooler and wet Nyandarua do not spend lots of time foraging (since food may to be readily available and abundant), hence they have more time to defend themselves against lice (preening, dust- bathing) than birds in the lower, warmer Nakuru where birds could be spending more time looking for food. Although lice prevalence differed significantly between the two host species and habitats, it would be interesting to find out if the same patterns would be observed if the same study was conducted over a longer temporal scale.

The fourth objective of this study that investigated whether there was a relationship between host’s body mass and louse abundance concludes that the null hypothesis (i.e. lice abundance 69

does not affect body condition of adult hosts) was accepted for both host species. Therefore, the number of lice per individual host does not necessarily affect the host’s body weight

(mass). However, a high infestation rate has the likelihood that the host may concentrate on control measures to reduce the parasite load hence divert attention from important activities like foraging, which consequently would lead to a poor weight gain especially if this was over an extended period of time. Testing such a hypothesis would require a controlled experiment where several factors other than the two under consideration are controlled.

Furthermore, body mass is extremely variable e.g. between morning and evening depending on the feeding times of the host species, and between a female with an egg about to be laid and one without. Therefore, presence of lice on a host is not an important factor in influencing its body mass. Unlike lice, weight was observed to be normally distributed

(Shapiro-Wilk W test: Speckled Mousebird = 0.982; Red-capped Lark = 0.995).

Although bird species in Kenya are relatively well known, including resources on avian identification (important for accurate ectoparasite-host association records), knowledge of their louse fauna and parasites in general is scanty. The parasitic lice have both medical and veterinary importance not only in wildlife and livestock systems but also in humans.

According to some authors for example, Dik et al. (2011), many louse species remain to be discovered. Knowledge on avian lice still has a paucity of information (for example Valim &

Weckstein 2013). Because of this incomplete knowledge on avian lice of birds of Kenya, many more new host records and indeed louse species will certainly be discovered in future studies, and hence, the five genera of lice collected in this study require further taxonomic work to determine what species they are. Phthiraptera and other parasite studies therefore should form important components of biodiversity research in Kenya.

Bird lice are of little concern to public health concerns because they cannot survive or reproduce off the body of the avian host and do not transmit human pathogens if they bite

(Clayton, Adams & Bush 2008). The findings of this study that social species of hosts are likely to have a higher prevalence could find relevance in poultry production systems in that flocking of birds (for example chickens, ducks, quails etc.) has the potential of a parasite

(whether internal or external) spreading fast among the birds. This is particularly so if birds are kept under crowded conditions and are in poor health (Clayton, Adams & Bush 2008).

Therefore, regular inspection and hygiene observations could help in reducing outbreaks and spread of parasites such as lice that heavily rely on body-to-body contacts of conspecifics for dispersal. Habitat, environmental factors and age of host are important factors to consider when handling a disease or parasite outbreak since they would affect spreading in one way or the other. The areas where this study was conducted are undergoing rapid developments in terms of changes in land use. In Nyandarua, land subdivision is leading to a reduction in suitable habitats for bird most species, with grassland and forest species being affected most.

In Naivasha, there is an increasing acreage of native land conversion to horticulture and settlements (urbanisation and real estates). These changes in land use will undoubtedly have profound effects and impacts on native and resident bird species that will indirectly or directly affect the parasite species patterns as well.

6.2 Recommendations

6.2.1 Species management

An increasing loss of native habitat for birds, not only in Nyandarua and Naivasha but also in most others areas in Kenya, will affect bird species populations, their distribution and many other things such as their parasite biodiversity species richness and parasitic patterns. This is important because both hosts and their parasites have an intimate evolutionary relationship. It is therefore important to note here that as much as development is needed in this nation, we 71

should secure and protect tracks of land in their native forms so that we can protect and conserve biodiversity. Knowledge that lice infestations can have negative effects on wild birds under certain conditions. Wildlife managers should therefore be informed of potential consequences that lice may have on individual hosts or entire host populations such as blood loss (anaemia), feather damage, irritation, and possible transmission of endoparasites and pathogens (Clayton, Adams & Bush 2008). It should also be noted that an increase in infestation or infection by a parasite may increase the probability of host mortality (Hatcher

& Dunn 2011).

6.2.2 Further research

i. Additional research on ectoparasite patterns between social (gregarious, colonial)

birds (for example Grey-capped Social Weaver Pseudonigrita arnaudi, Superb

Starling Lamprotornis superbus) and territorial birds or those that form pair bonds

(for example Banded Parisoma Sylvia boehmi, Ring-necked Dove Streptopelia

capicola) in the tropics are important to understand parasitic patterns in host groups

wi-th different social and breeding behaviours.

ii. Another approach to (i) above would be to conduct research between various mating

systems e.g. monogamous vs polygamous (both polygynous and polyandry). In the

monogamous species, it would be interesting to find out whether louse loads between

the paired mates differ since host individual’s body contacts is the principal way that

lice is transmitted between hosts during for example during copulation, display and

sharing of nest activities (Potti & Merino 1995). iii. Research is needed to compare prevalence and abundance of ectoparasites across

ecosystems using species that have a wider distribution in various habitats. This shall

help to better understand the role of environmental variables in occurrence,

distribution, prevalence and intensities of parasites. 72

iv. The interaction of various groups and species of ectoparasites on the same host is also

worth investigating, as is the host’s annual cycle (seasonal) for distribution of

ectoparasite on a given host. v. Funding on avian ectoparasites needs to be made available from the Government and

nongovernmental funding agencies so that more researchers are trained and given the

realisation of the potential role played by ectoparasites as vectors of emerging

pathogens and diseases. Research should not only focus on ectoparasite but also on

endoparasites in a variety of vertebrate hosts when an opportunity arises e.g. from

accidental deaths. vi. The fact that Philopterus sp. was the rarest genus recorded in Red-capped Lark, and

that it was more prevalent in birds in Naivasha, needs to be investigated further. The

three individuals infested by this louse genus were sampled at Heni (in Nyandarua)

which is on the boundary between two habitats and since this population had been

absent from the site until late during the study period, it is also possible that Red-

capped Lark populations are moving between the two habitats or even wider.

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APPENDICES

Appendix I: Descriptive statistics for lice infestation for each of Speckled Mousebird’s sampling sites.

No. Prevalence Mean Mean Lice Elevation Range Examined (%) Abundance Intensity Population (meters)

Nakuru County Camp Carnelly's 40 100 26.08 26.08 1 - 177 1043 1907

Elsamere Field Study Centre 8 100 22.75 22.75 8 - 45 182 1913

Fisherman's Camp 22 100 18.86 18.86 1 - 58 415 1907

Marula Estates Ltd. 23 95.7 23.32 24.23 1 - 196 534 1896

Soysambu Conservancy 23 87.0 10.91 12.55 1 - 33 251 1857

Nini Farm 20 100 15.85 15.85 7 - 53 317 1893

Naivasha Owls Centre 5 80 5.40 6.75 3 - 13 27 1906

Tony Seth-Smith's 5 100 14.80 14.80 3 - 41 74 1909

Nyandarua County Njabini (Githaiga's Farm) 6 100 12.00 12.00 4 - 23 72 2538

Njabini (Kihiu's Farm) 12 75 13.00 17.33 3 - 40 156 2519

Njabini (Lydiah's farm) 5 20 0.20 1.00 1 1 2570

Njabini (Maingi's Farm) 7 100 8.71 8.71 2 - 17 61 2576

Njabini (Muhindi's Farm) 4 75 5.25 7.00 1 - 15 21 2528 Njabini (Soil Conservation - 18 61.1 7.39 12.09 3 - 34 133 2538 KARI) Nyahururu (Ol’ Joro Orok 37 83.8 10.24 12.33 1 - 59 379 2380 Agric. Training Centre) Nyahururu (Wamiti's Farm) 3 100 6.67 6.67 5 - 9 20 2513

Nyahururu (Fatuma's Farm) 6 100 18.17 18.17 5 - 56 109 2394

Nyahururu (Ngigi's Farm) 9 66.67 8.22 11.50 3 - 19 74 2409 Nyahururu (Uaso Narok 16 100 49.13 49.13 6 - 161 786 2343 Forest Reserve)

Appendix II: Descriptive statistics for lice infestation for each of Red-capped Larks’s sampling sites.

No. Prevalence Mean Mean Lice Elevation Range Examined (%) Abundance Intensity Population (meters)

Nakuru County

Longonot Plains (1) 17 11.8 0.18 1.5 1 - 3 3 2073

Longonot Plains (3) 9 33.3 0.89 2.67 2 - 4 8 2107

Longonot Plains (4) 15 33.3 1.27 3.80 1 - 9 19 2070

Longonot Plains (5) 118 19.5 1.24 6.35 1 - 20 146 2037

KARI Block 16 10 20.0 1.70 8.50 1 - 16 17 1891

Nyandarua County

Murungaru (Joshua) 3 0.0 0.00 0.00 0 2440

Murungaru (Ndaraca 2) 5 0.0 0.00 0.00 0 2595

Njabini (Heni) 25 28.0 1.60 5.71 1 - 16 40 2560

Ndaragwa (Mairo Ikumi) 22 27.3 0.82 3.00 1 - 7 18 2501

Ndaragwa (Mahihu Farm 1) 52 7.7 0.11 1.50 1 - 2 6 2377

Ndaragwa (Mahihu Farm 2) 18 11.1 0.41 3.50 1 - 6 7 2336

Nyahururu (Gatumbiro) 2 0.0 0.00 0.00 0 2341

Nyahururu (Kianjata) 31 6.5 0.58 9.00 8 - 10 18 2340