From 1993-95, the behavioural ecology of the lapwing Vanellus vanellus L. was studied in Upper Teesdale, Co. Durham, with the aim of describing the behavioural mechanisms underlying some population characteristics. Significant effects of age and individuals were found in many aspects of Lapwing breeding biology. Older Lapwings returned to the breeding grounds before yearlings, with adult males returning earliest of all. First breeding attempts occurred at one-year-old for most females, but at two-years-old for most males. Males two-years-old and over showed a remarkable degree of consistency in breeding status (breeding or non-breeding) in consecutive years, even where this meant persistent non-breeding. The age of first breeding, and consistency of breeding status among males, indicates intense intermale competition for limited breeding habitat, with some males, perhaps of low quality, apparently permanently prevented from breeding. However, few differences in annual breeding success were found among females of different ages. With the exception of egg size in first clutches, where yearling females laid eggs around 5% smaller than adults, yearling and adult females were similarly fecund. Laying dates and egg volumes in first clutches exhibited high indices of repeatability between years, probably reflecting a high degree of heritability of these traits. High frequencies of polygyny were recorded, despite the traditional view of strict monogamy for this species. The mating success of male Lapwings increased between one and three years-of-age. The distinct parental roles of the sexes facilitated the occurrence of polygyny by reducing activity-budget costs of polygynous associations for both sexes. Polyterritoriality, polyandry and double-brooding were also recorded and discussed.

In this study, I first describe distribution and abundance of breeding Eared Grebes {Podiceps nigricollis) in British Columbia. Second, I characterize and examine the relationships between nesting habitat and nest site selection on breeding group size. Finally, I. examine effects of colony size, nesting chronology and nesting synchrony on reproductive success at Eared Grebe colonies. I surveyed 421 wetlands in 1985 and 1986 and located 47 lakes used by nesting Eared Grebes. Those 47 lakes accomodated from a low estimate of 1761 to a high estimate of 4474 pairs. Breeding abundance, calculated from adult, nest and young counts, ranged from single pairs to more than 590 pairs per lake. Breeding took place in shallow lakes of various sizes, subject to extensive variations in water levels. Breeding abundance was positively correlated with lake area. Fewer breeding pairs utilized nesting areas close to shore (in shallower water) than nesting areas far from shore (in deeper waters). Nesting areas close to shore were found in smaller lakes and were used less often in consecutive years than nesting areas far from shore, presumably because of lower habitat predictability. An experiment with unattended artificial nests showed that nest predation was higher far from shore than close to shore. Nesting areas close to shore were used by small groups. These maximized concealment by being located in denser vegetation. Nesting areas far from shore were used by larger groups and were located in more open areas. On both years, adults arrived at nesting lakes in April and May, started laying on 27 May and departed from, nesting areas in late July and- early August. Nesting was significantly earlier and reproductive success per pair was significantly higher in 1985 than in 1986. A .stepwise multiple regression examined effects of colony-size, synchrony and chronology on nesting success. Only nesting chronology accounted for differences in nesting success. Late nesters were not birds attempting to renest. Instead, there appeared to be qualitative differences across colonies that were related to ages of breeders. Eared Grebe colonies are likely not formed from passive aggregation at limiting resources and there are likely no foraging benefits from colonial nesting. Nesting colonies could increase detection and mobbing of predators, but no evidence supported this. Anti-predator benefits of coloniality might have been masked by differences in breeding chronology and synchrony, or were missed because of low sample size. / Science, Faculty of / Zoology, Department of / Graduate

Thesis (M.Sc. (Zoology)) --University of Limpopo, 2009 / The aim of this study was to determine the breeding habitat of Blue Crane (Anthropoides paradiseus) by investigating the home range, habitat selection and habitat suitability. Geographic Information System (GIS) was used as the main tool for analysis. Home range sizes of Blue Cranes were studied during the breeding season using direct observation method. A 50% and 95% Adaptive Kernel was used to estimate home range sizes. The home range sizes were 9.0 ha and 43.5 ha for 50% and 95% Adaptive Kernel, respectively. All the nests were located within 50% Adaptive Kernel, often referred to as core area. The nests were located in agricultural land (mainly pasture) and close to water sources. Habitat selection was studied at nest sites (n = 74) and random sites (n = 200) following site attribute design. The Blue Crane showed a preference to breed in agricultural lands, close proximity to water sources, higher elevation areas, within north eastern sandy highveld vegetation, and north facing slope. The Blue Crane also avoided anthropogenic factors such as built-up land, roads and railway line. ModelBuilder extension of ArcGIS software was used to construct a breeding habitat suitability model for Blue Cranes. Nine habitat variables (water source, slope, aspect, elevation, land use, vegetation, built-up land, roads and railway line) were used in the model. The model was constructed using reclassify and weighted overlay command. Highly suitable sites accounted for 601, 448 ha, while moderately suitable sites accounted for 823, 593 ha, and least suitable sites accounted for 3, 000, 153 ha. This study demonstrated the effective use of GIS technology in analysing the breeding ecology of Blue Crane. The GIS technology provided capabilities for capturing and analysing varied and large data. It was also evident that availability of accurate and complete species data remains vital to enable the full utilization of the GIS technology.

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No description available.

Global climate change is expected to increase the frequency of extreme and unpredictable weather in many parts of the world. As a result, a critical goal for biologists is to predict how organisms may come to cope with increased environmental variability. The key to making these predictions will be to understand how animals currently living in fluctuating environments are able to survive and reproduce under these conditions. Sociality (i.e. group living) and cooperative breeding (i.e. where more than two individuals care for young together) may both facilitate the colonization of highly fluctuating environments. However, the relative benefits of group living and engaging in alloparental care under variable conditions remain unclear. My dissertation examines the fitness consequences of living in one of the world’s most unpredictable habitats—the African savanna—in a population of free-living cooperatively breeding superb starlings (Lamprotornis superbus). In chapter 1, I examine whether adults benefit from living in large social groups of up to 50 individuals, which are among the largest known for any cooperatively breeding bird. In addition, I test whether group size serves to buffer against harsh environmental conditions. In chapter 2, I examine whether breeders gain reproductive benefits by having alloparents at their nest—I explore the type of reproductive benefits gained (i.e. improved reproductive success versus offspring care load-lightening), as well as whether these benefits occur in both harsh and benign conditions (i.e. temporal variability hypothesis), or are greatest under harsh conditions only (i.e. hard life hypothesis). In chapter 3, I explore whether offspring care load-lightening reduces the cost of reproduction incurred by breeders and alloparents by comparing four physiological mechanisms known to mediate reproductive costs. Lastly, in chapter 4 I test the long-standing assumption that cooperatively breeding species face reduced costs of reproduction by sharing offspring care relative to non-cooperatively breeding species. I compare the oxidative cost of reproduction in superb starlings to greater blue-eared glossy starlings (L. chalybaeus), a synoptic non-cooperatively breeding species. Taken together my dissertation findings demonstrate that group living and alloparental care do not solely buffer against harsh conditions in superb starlings, but instead provide individuals with the flexibility to modify their offspring care behavior according to environmental conditions, to the behavior of other group members, and to their physiological condition prior to breeding—this behavioral flexibility may in turn serve to mitigate fluctuations in the cost of living and breeding in variable environments.

No description available.

No description available.

Thesis (Ph.D.)--University of Wollongong, 2004. / Typescript. Includes bibliographical references: p. 160-170.

The general biology of the South African Cliff Swallow Hirundo spilodera was studied over a two year period in the central Orange Free State. This species is highly colonial, nesting mostly on man-made structures such as concrete road bridges. Adult birds were usually faithful to their breeding colony and very few individuals changed colonies. The Cliff Swallow had a surprisingly large vocal repertoire for a swallow and contact calls of the young were individually recognizable. Three species-specific ectoparasites parasitized the Cliff Swallow but none seemed to have a noticeable negative effect on the swallows. Breeding started earlier in larger colonies than in smaller ones and conspecific brood parasitism was a common feature in some colonies. Individual pairs made up to four breeding attempts per season. The findings of this study are compared with the available information on other members of the Hirundinidae and the advantages and costs of Cliff Swallow coloniality are discussed.