This study examined the breeding ecology of the house sparrow, Passer domesticus, in Kentucky, USA, with particular regard to sexual selection, infidelity and parasitism. These aspects were also examined, to a lesser extent, in an archipelago population in Helgeland, Norway. Male badge size, a character posited to be under sexual selection, did not appear to influence reproductive success. Large-badged males produced more fledglings within a season than small-badged males, although this was not significant after controlling for time of breeding. Large-badged males did not commence breeding earlier than small-badged males, they were not paired to higher quality, more fecund females, and their young did not fledge in better condition. Badge size was not related to an individual's age or condition, and although badges varied in their degree of asymmetry, this was not related to any measures of reproductive success. Badge size did not influence reproductive success in Helgeland. The level of extra-pair in both populations was relatively low [10.3% of young in Kentucky, 4% of young in Helgeland (based on retrospective identification of parents)]. No extra-pair fathers were assigned, although there were no obvious pheotypic differences between males which were cuckolded and those with complete paternity within their broods. There was no association between cuckoldry and either infertility, breeding synchrony or density. Males appeared to rely upon frequent copulation as opposed to mate guarding as their main means of paternity protection. Copulation rates were unrelated to male sperm reserves as measured by the size of their cloacal proturberance. Females did not adjust the sex ratio of their brood in response to their own physical condition or the attractiveness or quality of their mate. Hatching asynchrony and brood reduction were both common in Kentucky, although the two phenomena were not associated.

No description available.

No description available.

Nutrition is profoundly important for practically all aspects of life. Getting enough of the right kind of food affects cellular function and energy acquisition, disease avoidance, mate attraction, trophic interactions and hence ecosystem structure. When nutritional needs are inadequately met, fecundity and survival can be adversely affected. However, the severity of these effects, and the importance of the particular life history stage when they were experienced, is incompletely understood. Understanding how and when nutritional conditions affect fitness is particularly important for the conservation of endangered species, especially when food supplementation is a key part of managing the few populations that remain. In this thesis, I explore the importance of nutrition during early- and adult-life for the hihi (Notiomystis cincta), a colourful, sexually dichromatic endangered New Zealand passerine. I begin by investigating the importance of nestling nutritional environment for the expression of colourful plumage in adulthood. By experimentally supplementing nestlings with alternative dietary treatments, I demonstrate that early life nutritional conditions have long-term consequences for the expression of both carotenoid-based and structurally produced plumage features. Next I investigate whether these colourful plumage traits are sexually selected. I show that different components of a male’s colourful plumage, including yellow carotenoid-based, black melanin-based and white structurally-based colour, are relevant for different aspects of reproductive success. Using the dietary supplementation experiment, I also consider the impact of alternative supplementary foods on the growth and subsequent survival of hihi. I show that directly supplementing nestlings with protein has a negligible long-term survival benefit over supplementing carbohydrates, and present evidence that males and females have divergent nutritional needs during development – an important consideration for any supplementary feeding program. Finally, I consider whether moulting male hihi selectively forage for carotenoid-rich foods in the wild, as would be expected in a species that requires these pigments for sexual display. I present evidence that adult male hihi do indeed target carotenoid-rich foods during moult, which is consistent with the suggestion that dietary carotenoid access maintains signal honesty. In short, by addressing evolutionary questions from a nutritional perspective, I discover how and when investment in key life history traits is prioritised, how this differs between the sexes and show how this knowledge might be used in supplementary feeding programs to the benefit of endangered species.

No description available.

No description available.

No description available.

No description available.

No description available.

The aim of this project was to elucidate the mechanisms behind maternal inbreeding depression, using a model avian species, the zebra finch Taeniopygia guttata. Inbreeding can reduce the fitness of inbred animals beyond its negative effects on early survival, through reduced fecundity of inbred animals that survive to reproductive age. In particular, inbreeding has been found to cause a decline in hatching success and early survival of the offspring of inbred mothers. I examined the underlying causes of maternal inbreeding depression by observing the effects of one generation of full-sibling mating on life-history and physiological traits in the zebra finch. The aims of this project were to separate the effects of maternal inbreeding on egg production and subsequent offspring care on the fecundity of inbred females and to examine the possible underlying causes of maternal inbreeding depression. The study explored the following questions; • Does maternal inbreeding lead to a reduction in egg production, either in the number, quality or size of eggs produced? • Do inbred females reduce the level of antimicrobial proteins in their eggs compared to outbred females? • Does inbreeding lead to a reduction in either incubation attentiveness or incubation temperature in females? • Does inbreeding in the egg-laying mother lead to a decline in offspring survival or growth? • Does inbreeding in the foster mother lead to a decline in offspring survival or growth? • Do inbred birds have higher maintenance costs, i.e. higher resting metabolic rates than outbred females? After generating inbred and outbred (control) females from full-sibling and non-related pairs respectively, females were paired with unrelated outbred males at the age of around six months old. The first clutch was removed for analysis of egg production (chapter two). The females were immediately allowed to lay replacement clutches, which were cross fostered among nests of inbred and control females. I then compared incubation attentiveness between inbred and control females using this replacement clutch (chapter 3). Through the cross fostering design I was able to separate the effects of inbreeding in the egg laying (chapter 2) and incubating mother (chapter 3) on offspring viability by comparing offspring growth and survival between treatments. When the same group of females were two years old I compared the resting metabolic rate of inbred and control females by measuring oxygen consumption of resting females in an open flow respirometry system (chapter 4). In chapter two I examined the effects of inbreeding on a key stage of reproductive investment; egg production. I found a reduction in both egg mass and yolk mass in inbred females compared to control females. However, there was little evidence to suggest that the level of antimicrobials deposited to the egg differed with the inbreeding status of the female. Inbreeding in the egg laying mother was found to affect hatchling mass through interactive effects with replicate and clutch size. Inbreeding in the egg egg-laying mother also affected post-hatching survival, although this effect was mediated by hatching order. In chapter three I investigated the effects of maternal inbreeding on incubation behaviour. Inbred females reduced their incubation attentiveness, but did not reduce average incubation temperature, compared to control females. However, the overall incubation attentiveness experienced by clutches did not differ between treatments due to complete compensation by the partners of inbred females. This is perhaps why there was no significant decline in either hatching success or hatching mass of offspring cross fostered to inbred females. In chapter four I examined the effects of inbreeding on resting metabolic rate by measuring resting oxygen consumption (VO2) of inbred females compared to control females. Resting VO2 (corrected for body size) was higher in inbred compared to control females. Inbred females also showed increased central organ mass (heart plus liver) for their body size compared to control females. Resting VO2 (corrected for body size) was positively was correlated with central organ mass (corrected for body size) and negatively correlated with peripheral organ mass (corrected for body size). I also found a positive correlation between resting VO2 and the ability to evade capture (rank capture order from a flight aviary). My results suggest that the reduced survival rates of the offspring of inbred females may be caused by reductions in maternal investment, since both egg size/quality and incubation attentiveness have previously been found to positively correlate with offspring viability. The finding that resting VO2 increased with inbreeding may suggest that inbred females showed reduced maternal investment in egg production and incubation attentiveness due to higher energetic costs of self-maintenance. Resting metabolic rate has been found to be associated with a wide range of life-history traits and so this finding could have important implications for the fitness of inbred animals. These findings are novel and shed light on the previous observations that maternal inbreeding can reduce early and long-term survival of the offspring of inbred individuals in wild populations.