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The eastern race of the Loggerhead shrike (Lanius ludovicianus ssp. migrans) is a grassland bird federally listed as endangered. There are approximately 30 pairs remaining in the Canadian wild today. Captive breeding and release programs have been developed in Canada to help alleviate the decline. However, little is known about the fate of the released birds and the factors influencing their reproductive success. To help in the understanding of the movement, behaviour and survival of the shrikes post-release, we tested whether radio telemetry was an effective technique to follow these birds. Despite limited behavioural effects in captivity, a tail-mount was not suitable for released Loggerhead shrikes due to unreliable retention times. The second portion of this study addressed the factors influencing reproductive success in captivity, including breeding behaviour and individual characteristics. Distance between individual pairs in their cages, female nesting activity and male origin were the best predictors of success. Recommendations for managers are made.

Cattle grazing in riparian zones can have large impacts on vegetation characteristics and avian biodiversity. To assess these impacts in southern Alberta, vegetation and bird surveys were conducted in twelve riparian sites (four each in heavily grazed, moderately grazed, and ungrazed habitats) along the Oldman River. The shrub understory and bird species diversity and abundance declined significantly as grazing intensity increased. Settlement patterns, territory sizes, and food provisioning rates of some bird species were examined to assess the mechanisms behind this reduction. Five out of seven species settled earlier in ungrazed habitats, whereas two species did not show any discernable settlement pattern. The territory sizes of three species examined increased as grazing intensity increased. House wrens (Troglodytes aedon) brought more food and more food biomass to their nests in ungrazed habitats. These results indicate that available food biomass decreased as grazing intensity increased, and is an important factor in population dynamics of some species. / 29 cm.

The Wattled Crane, Bugeranus carunculatus Gmelin, is presently classified as being 'Critically Endangered' within South Africa according to the Eskom Red Data book of Birds of South Africa, Lesotho and Swaziland, with a population of a meagre 235 individuals. Of this, 85% occur within KwaZulu-Natal and live predominantly on privately owned agricultural land. As a result thereof, Wattled Cranes and agriculture compete for the same resources. Up until now, the loss of viable habitat, as a result of agricultural development and afforestation, has been mooted as being the primary reason for the decline in numbers of the species. The advancements in the Geographical Information Systems field have enabled conservationists to acquire data, especially pertaining to habitat requirements, which were previously unattainable. This improved data acquisition is enabling for more informed decision making and better allocation of resources. The study therefore attempts to make use of a Geographical Information System to determine whether or not differences exist within the home ranges of active and historical Wattled Crane nesting sites, utilising the National Land cover database. The updated Land cover data for South Africa, although not completed at the time the present study took place, allowed for the interrogation of the various Land cover classes within an estimated home range. Natural Grassland was the predominant Land cover type within both active and historical home ranges, whilst both active and historical home ranges were subject to some degree of transformation. The potential impact of management practices in and around nesting sites warrants further investigation because this could not be determined through the analysis of land cover. / Thesis (M.Env.Dev.)-University of KwaZulu-Natal, Pietermaritzburg, 2006.