Show simple item record

dc.contributor.authorWhitehead, Joanna K.en
dc.date.accessioned2008-11-18T01:14:44Z
dc.date.issued2007en
dc.identifier.urihttps://hdl.handle.net/10182/640
dc.description.abstractKakapo (Strigops habroptilus) are a flightless, nocturnal parrot endemic to New Zealand. Thought to be extinct within their natural range, kakapo are currently listed as nationally critical. The current population of 86 individuals is managed by the Department of Conservation’s National Kakapo Team on two offshore islands in southern New Zealand, with all females of breeding age on Codfish Island (Whenua Hou). Kakapo only breed once every two to five years, coinciding with the mast fruiting of specific plant species. On Codfish Island, the proportion of adult female kakapo that breed in rimu (Dacrydium cupressinum) fruiting years is dependent on the quantity of fruit produced, with fewer females attempting to breed during low mast years. The purpose of this research is to investigate why only some adult female kakapo breed in low rimu fruiting years on Codfish Island, specifically assessing if foraging home range size and/or habitat selection influence breeding. A total of 506 location points were collected at night for 18 adult female kakapo between March and May 2006. These were used to estimate foraging home ranges and to assess if kakapo select for particular types of vegetation. Ecological Niche Factor Analysis was used to determine the relative importance of habitat variables in the distribution of female kakapo and to predict areas of suitable breeding habitat when rimu fruit is limited. The breeding success of individuals in 2005, a low rimu mast year, was used to identify if differences in home ranges or habitat selection occurred between breeding and non-breeding females. The large variation in foraging home range sizes recorded in this research was consistent with previous studies. Foraging home range sizes were on average twice the size for breeders than for non-breeders, suggesting that adult female kakapo may be limited in their ability to breed by the size of the area they occupy. Adult female kakapo did not randomly use vegetation on Codfish Island as some vegetation types were not used, while others were common inside foraging home ranges. Adult female kakapo utilise a broad niche and are capable of surviving in a wide range of habitats. However, breeding females were more specialised in their niche requirements than non-breeders, with breeders utilising areas with higher abundances of mature rimu trees. Females occurred in high elevation, flat areas of the island but this may have been because this is where appropriate vegetation types occurred. During low rimu mast years, breeding adult females were predicted to occupy habitat in high elevation, plateau areas with a high abundance of rimu. Areas identified as sub-optimal habitat for breeding included the coastal areas, the lower elevation area of the main valley and some ridgelines. The home ranges of all 10 breeding females contained some optimal habitat, while females who did not breed were more likely to be located in sub-optimal habitat. Although there were significant areas of optimal breeding habitat not occupied by adult female kakapo, other kakapo may have been present in these areas. To increase the proportion of females that breed in low rimu mast years, it may be necessary to remove sub-adult females or surplus adult males living in optimal breeding habitat from the island. Alternatively, females in sub-optimal breeding habitat could be fed supplementary foods or transferred to other islands where there is unoccupied suitable breeding habitat available.en
dc.format.extent1-134en
dc.language.isoenen
dc.publisherLincoln Universityen
dc.subjectKakapoen
dc.subjectStrigops habroptilusen
dc.subjectCodfish Islanden
dc.subjectradio-trackingen
dc.subjecthome rangeen
dc.subjecthabitat selectionen
dc.subjectEcological Niche Factor Analysisen
dc.titleBreeding success of adult female kakapo (Strigops habroptilus) on Codfish Island (Whenua Hou) : correlations with foraging home ranges and habitat selectionen
dc.typeThesis
thesis.degree.grantorLincoln Universityen
thesis.degree.levelMastersen
thesis.degree.nameMaster of Scienceen
dc.subject.marsdenFields of Research::270000 Biological Sciences::270700 Ecology and Evolution::270708 Conservation and biodiversityen
lu.contributor.unitLincoln Universityen
lu.contributor.unitBio-Protection and Ecologyen
pubs.organisational-group/LU
pubs.organisational-group/LU/BPEC
pubs.publication-statusPublisheden
dc.publisher.placeLincoln, Christchurchen


Files in this item

Default Thumbnail

This item appears in the following Collection(s)

Show simple item record