The spatial ecology of yellow-eyed penguin nest site selection at breeding areas with different habitat types on the South Island of New Zealand
Clark, Ryan D
The yellow-eyed penguin (Megadyptes antipodes), or hoiho, is an endemic and endangered species of conservation importance in New Zealand. A primary management strategy for the conservation of the hoiho population along its South Island range is the restoration of coastal habitats that are thought to be traditionally preferred by the species and therefore most suitable for nesting. Improving the knowledge and understanding of the factors that influence the nesting habitat selection of hoiho at different scales would increase the effectiveness of habitat restoration initiatives and other habitat-related management activities. Hoiho are considered non-colonial breeders as nest sites in a breeding area are usually well concealed and spaced 20m apart from each other on average. This solitary nesting behaviour may be due to a requirement for adequate protection from insolation. However, it has been suggested that the visual isolation of a nest site from neighbouring conspecific nests is important for hoiho. This study aimed to determine the relative importance of these and other potentially significant factors affecting the selection of nest sites by hoiho and their distribution in breeding areas with different nesting habitats. To determine the importance of visual isolation relative to protection from insolation, the distance from which nest sites were visible, and the extent of nest site cover, were compared with that of random sites in flax, scrub and forest nesting habitats. Results indicated that visual isolation of nest sites is likely a consequence of hoiho selecting sites comprised of micro-habitat features that provide a high level of protection from insolation. Subsequently, the distribution of nest sites within the three different nesting habitats appeared to be influenced by spatial variation in the micro-habitat features that provided the nesting conditions preferred by hoiho. In addition to micro-habitat features, the selection of nesting habitats by hoiho, and their distribution within a breeding area may be influenced by factors operating at a broader, landscape level. To examine the potential influence of landscape features such as slope and the distance of nesting habitats from the shore, a geographic information system was used to construct simple spatial nesting habitat selection models for two hoiho breeding areas on the Otago Peninsula. The model indicated that the distribution of nesting habitats selected by hoiho in the two study areas appeared to be influenced primarily by a combination of the slope and the habitat types (i.e. vegetation cover) that contained the micro-habitat features preferred by hoiho. The models contribute to improving the understanding of hoiho nesting habitat selection, and can provide a rigorous basis for determining where habitat management activities should be focussed in a breeding area to achieve optimal results.
Advisor: Seddon, Philip; Mathieu, Renaud
Degree Name: Master of Science
Degree Discipline: Zoology
Research Type: Thesis
Description: ix, 82 leaves : col. ill., maps ; 30 cm. Notes: Thesis typescript. University of Otago department: Zoology. "21 December, 2007." Thesis (M. Sc.)--University of Otago, 2008. Includes bibliographical references.