1) This study investigated the costs and benefits of a polygynous mating system, and its effects on reproductive success and parental care in male and female com buntings (Miliaria calandra), on North Uist, Outer Hebrides. In 1989 and 1990, 41.2% of males were monogamously paired, 33.3% polygynous and 23.5% unpaired; the sex ratio was 1:1. Polygynous males usually paired with two females; occasionally three. The distribution of females among males was not significantly different from a binomial distribution. 2) DNA fingerprinting showed that there were only two possible cases of extra-pair paternity (EPP) due to extra-pair copulation (EPC) (4.5% of 44 offspring; 6.7% of broods), both from the same brood. There were no cases of intra-specific brood parasitism (IBP) (0% of 50 offspring; 0% of 16 broods). EPP was probably rare because of mate guarding by the male, asynchrony between broods for polygynous males and limited opportunities for EPC. Polygynous males fledged more offspring from their territories than did monogamous males because they paired with more females; unpaired males fledged no offspring. 3) Unlike most other polygynous birds, primary and secondary females of polygynous male com buntings had similar reproductive success and both had greater reproductive success than monogamous females. Monogamous females had lower reproductive success because their chicks starved more often. Although monogamous females provisioned nestlings at a similar rate to females of polygynous males, monogamous females delivered smaller food loads, which may have led to the reduced success of those nests. 4) Males rarely fed nestlings before they were four days old. Males provided less food for nestlings than did females at all chick ages and, on average, provided a maximum of only 22.0% of all feeds. Unusually for a polygynous species, males provisioned nestlings of monogamous, primary and secondary females with similar sized food loads and at similar rates. 5) Broods belonging to primary and secondary females were apparently equally valuable to their males because EPP was low in this population and brood sizes were similar between nest classes. Males may have been able to feed both nests because they were temporally separate, although at least one male was able to feed overlapping nests simultaneously. Males provisioned proportionately less than females at early stages of the nestling period, possibly because of sex differences in other available reproductive opportunities. Females had no better available option than to provide parental care to the current brood, whereas males could potentially increase their fitness better by defending a territory in which females could breed. 6) Males appeared to defend areas in which females chose to nest rather than to forage. Females often foraged outside male territories. The territories of unpaired, monogamous and polygynous males did not differ significantly in habitat composition. 7) Female corn buntings neither suffered costs to polygyny, nor did they compete for resources, such as male parental care, nest sites or food. Nests were under-dispersed in space, because of habitat aggregation, and were randomly dispersed in time within territories. Primary and secondary females of polygynous males did not choose territories in the same order, and the first settling females of polygynous males did not settle significantly earlier than monogamous females; this suggests that males were chosen randomly, rather than by the quality of their resources. I suggest that low variance of male territory quality facilitated random female choice of males. A no-cost, no-benefit model, with females choosing males randomly is suggested as the best explanation for the maintenance of polygyny in the com bunting.

In this dissertation I shall describe a study of some aspects of territoriality in the Wren (Troglodytes troglodytes troglodytes Linn.) and the efficiency of song as a means of ensuring. exclusive use of a specific site. To aid understanding of the functions of territoriality in this species, feeding and song behaviour have been investigated, as also have possible mechanisms to reduce competition within the species and between the sexes, Information on breeding biology was also collected to attempt ·to relate this to territory size, The British population of the Wren has been steadily increasing since the severe winter of' 1962-63 when abnormally cold conditions drastically reduced numbers. Indeed the Wren is now considered as one of the more common resident birds (Batten 1973; Batten and Marchant 1975;1976). In the last 5-6 years maintenance of high populations of smaller birds, such as the . Goldcrest (Regulus regulus Linn,) and the Wren has been associated with a series of mild winters. It would appear from. this that the winter climate exerts ·a strong, though probably indirect, influence . upon the number of Wrens. The milder conditions have not led to such marked increases in numbers of larger birds such as the Blackbird (Turdus merula Linn.). It is thought that the territorial behaviour is the limiting factor to the maximum breeding density (Batten and Marchant 1976). However, the male Wren is claimed to be strongly territorial and to defend a specific site by song (Armstrong 1955}. Although Wrens have been known to sing at a!ll times of the year song output increases during the breeding season (Colquhoun 1940; Armstrong 1944; Cox 1944; Clark 1949).

It is well established that farmland bird population declines are strongly linked to the land use and management changes associated with increased agricultural intensification. In future, climate change is predicted to be an increasingly important driver of bird population changes. A substantial number of studies have investigated the large scale impacts of climate change on species’ distribution and abundance. However, few have examined in detail specific ecological impacts of climate change on bird demographics that would allow predictions of the effects of climate on bird populations. Here I show that below-ground prey form a key part of the diet, of my study species, the Starling Sturnus vulgaris, on UK grassland in both the breeding and non-breeding season. I then show that soil moisture mediates intake rates of below-ground prey using field experiments on wild-caught Starlings. Intermediate soils provided the best foraging opportunities with both saturated and dry soils being suboptimal I then linked delivery of below-ground prey to reproductive success. A study of adult provisioning of nestlings (n= 42 nests), over a four year period, established that the delivery of below-ground prey, specifically Tipulidae larvae, was mediated by changes in soil moisture and linked to Starling reproductive success via changes in fledgling survival. Analysis of fledgling success at a range of sites (n=132) provided evidence that an increase in the mean spring (April-June) soil moisture deficit over a twenty year period was a significant driver of Starling population dynamics in Britain; even after controlling for temporal changes in starling xi populations (likely to be linked to agricultural intensification). I conclude by discussing different management options to alter soil moisture levels on grassland to benefit both ground-probing birds and the impacts on a range of other ecosystem services (e.g. reducing flood risk).

During this study, various aspects of the breeding biology of the Swallow (Hirundo rustica) were investigated. Firstly, factors which affected the reproductive success of individuals in the population were examined. First brood clutch size was unrelated to laying date. The size of the second clutch was significantly affected by laying date, such that the later a second clutch, the smaller its size. The size of the second clutch was independently related to first brood laying date; when compared with those which had earlier first broods, late pairs had smaller second broods. Pairs which had only one brood laid significantly later than the first brood of pairs which laid more than one. The earlier breeders laid most eggs during the breeding season. Males and females differed significantly in only one biometric measurement, that of tail length. Males with breeding experience had longer tails and earlier first clutches than those with no breeding experience. One measure of tail length was significantly longer in females with breeding experience. These birds also had significantly higher body weights than their inexperienced counterparts. Females with breeding experience laid second broods slgnificantly earlier due to the shorter interval between fledging their first brood and laying the second clutch. Fledging success was highest on two pair farms where the birds were more likely to have a second brood. Secondly, instances of "strange" swallows appearing at occupied nests were discussed in the light of four hypotheses which have been postulated by other researchers to explain similar occurrences of this type of behaviour in the Swallow and other species.Visits are classed as attempted infanticide, helping, prospecting and interaction with neighbours. Visits by Swallows, in this study, which included aggressive interactions between "strangers" and nestlings, i.e.; attacking nestlings and the destruction of eggs, were deemed as infanticide. Visits when no interactions were observed, but when the visitor was a recent fledgling were defined as "prospecting". Juveniles and adults, which visit nests in the period before migration, may aid their future reproductive success by assessing the quality of breeding sites. Infanticide was a rare occurrence in this population probably because there were no unmated males. There were no helpers, probably due to the large number of available nest-sites and the roughly equal sex ratios. Neighbours may visit other nests during the breeding season for similar reasons. Thirdly, behaviour during feeding visits was examined. Adults were found to be allocating food at random among the nestlings. For nestlings, begging first was found to be the biggest predictor of obtaining food. The rank, by weight, of the nestlings was found to have no effect on their ability to acquire food. When the nestlings were small, adults alerted them to a feeding visit by the use of contact calls after they had landed on the nest As chicks got older, parents phased out contact calls and the nestlings started begging before the adults landed on the nest Fourthly, genetic paternity and maternity was determined using DNA fingerprinting on a sample of 39 families. In the population, extra-pair offspring were rare (3.4%), and intra-specific brood parasitism was found only once (0.3%). In the 5 cases in which paternity of the mis-matching offspring could be attributed, the genetic father was found to be breeding within 100m. In the 5 instances of mis-matching offspring which could not be attributed to any of the males breeding locally: these probably resulted from opportunistic extra-pair copulations involving males not breeding in the area. This study has tried to establish which effect the breeding success of the Swallows in this study. There is little, if any, comparable data from other studies of this species. In order to more thoroughly asses the theoretical significance, a longer study would need to be undertaken. This study has provided additional, anecdotal, evidence that Swallows engage in, at first glance, "abnormal" behaviours during the breeding season, for example; an adult was observed to attack nestlings on several occasions. Such events are rare, in both this and other studies, and it was not possible to reach definite conclusions relating to the occurrence of such behaviours. The single year's observations on the distribution of food to the nestlings was unable to address the underlying causes of behaviour but it did provide tantalising glimpses of possible explanations. The paternity survey carried out in this study has added to the body of evidence that extra-pair copulations do occur in this species. Features of adult birds, their habitat and breeding behaviour were related to the occurrence mis-matching offspring. These relationships have suggested further studies which could elucidate the factors driving individuals to engage in extra-pair copulation sas a complementary breeding strategy.

No description available.

No description available.

The hyper-diverse avian family Zosteropidae (~100 species) is renowned for its exceptional colonising ability and rapid recent diversification. The genus Zosterops dominates within the family, including over 70% of all recognised species, and is notorious for the phenotypic uniformity that has traditionally made designation of taxon boundaries within the genus difficult. While the last decade has seen an abundance of research focusing on colonisation abilities and speciation patterns of insular taxa, relationships between continental forms, specifically mainland African taxa, remain subject to great uncertainty. This thesis focuses on uncovering the relationships, origin and evolutionary history of African Zosteropidae. Chapter 1 introduces the family Zosteropidae, reviews the current literature that is based predominantly on insular systems. In introducing the African Zosteropidae complex, this chapter highlights questions associated with this group and presents the aims of the thesis. Chapter 2 focuses in on one of the most geographically complex areas within the African system, to explore the relative importance of past climatic fluctuations as a driver of diversification in Zosterops endemic to the isolated montane massifs of East Africa. Results provide the first molecular assessment of mainland African Zosteropidae and are used to examine alternative models of speciation. A dated molecular phylogeny demonstrates that divergence within African Zosteropidae is very recent (<5Ma) coinciding with periods of climatic instability during the Plio-Pleistocene. Furthermore, the non-monophyly of mainland taxa, specifically the polyphyletic nature of Z. poliogaster, leads to the rejection of a widely held assumption that the montane endemics of East Africa are relics of a previously widespread population. Instead results provide evidence for evolutionary model based on ancestrally adaptive populations. Chapter 3 attempts to further investigate relationships within the East African Zosterops and explores the usefulness of amplified fragment length polymorphism (AFLPs) in revealing inter- and intra-specific relationships. Resolution of relationships across the AFLP phylogeny is generally poor which is attributed to the low information content of the AFLP matrix generated. Bayesian hypothesis testing failed to provide support for various topological constraints tested and consequently this study was unable to confirm or reject the non-monophyly of East African montane endemics. Chapter 4 builds upon the molecular phylogeny of Chapter 2, by substantially increasing the taxonomic sampling of African species using DNA obtained from museum specimens. The use of both archive and fresh material enabled the largest genetic assessment of western Zosteropidae to date. Extensive sampling across Sub-Saharan Africa, the Indian Ocean region, the Arabian Peninsula and the Gulf of Guinea region reveals six major clades within the African Zosteropidae complex. Results confirm the widespread non-monophyly of mainland African species rendering current taxonomic arrangements invalid. GMYC (General mixed Yule-coalescent) analysis recovers 14 distinct evolutionary lineages within the African Zosteropidae system and provides a framework for further work using model-based species delimitation approaches. Finally, Chapter 5 draws together key findings from Chapters 2-4, and reviews how this work advances our understanding of the African Zosteropidae system. This chapter also highlights new gaps in our understanding of the western Zosteropidae and discusses several areas for future research.

No description available.

No description available.

The Scottish Crossbill, described as Lexis' curvirostra scotica, is shown to be more closely related to L.c.curvirostra than to L.pytyopsittacus (with which it had often been placed) in voice and morphology. Field studies in north-east Scotland revealed scotica and curvirostra breeding side by side, with considerable apparent ecological overlap, thus preventing their treatment as conspecifics. It is concluded that the Scottish Crossbill must be recognised as a full species, L.scotica. L. pytyopsittacus is confirmed as a valid species. Crossbill hind limb assymetry correlated with the direction of bill crossing is described. In an examination of redpoll museum skins, no difficulty was found in assigning supposed hybrids between Acanthis f.flammea and A, homemanni exilipes to one race or the other, and there appears to be no proof of hybridisation in the literature. It is concluded that hybridisation must be rare (or the hybrids are at a selective disadvantage) if it occurs at all. Similarly, the Icelandic birds, which are supposed to be a hybrid swarm, were found to fall into two plumage types with the same measurements, one like A.f'.roatrata (common) and the other like A.h.homemanni (rare). However, the bill length is significantly smaller than that of either supposed parental type, A.f .rostrata and A. h.homemanni. The evidence examined confirms the classification of redpolls into two species, A.flammea and A.homemanni, but the need for field studies is recognised. Reduced and carboxymethylated barb keratin (SCMK) from a variety of species were studied by electrophoresis on polyacrylamide gradient gels. Species-specific patterns were found for all the well-defined species examined, and the results suggest relationships which agree well with published classifications. The technique shows immense potential as a source of taxonomic information. When applied to the crossbills and redpolls the results confirm the very close relationships within these groups, and suggest further evidence of affinities between-races.