Publications Archive

Abstract: The critically endangered kuaka Whenua Hou (Whenua Hou diving petrel, Pelecanoides georgicus whenuahouensis) is a burrow-nesting petrel, restricted to breeding in the foredunes of Whenua Hou. The species’ recovery is inhibited by ongoing threats such as vessel-based light pollution, interspecific competition, and climate change including storm-induced erosion of fragile breeding habitat and thus, kuaka Whenua Hou would benefit from the establishment of a new colony through translocation. However, translocations of petrels require hand-rearing of pre-fledging chicks on the destination site to reset their philopatric behaviour. We documented a hand-rearing and translocation trial of kuaka Whenua Hou in preparation for future translocations. Ten kuaka Whenua Hou chicks were translocated from natal burrows to nest boxes installed behind the colony, and hand-reared on a bespoke diet of pureed sardines. All hand-reared chicks fledged successfully, with fledging mass similar to naturally-reared chicks and with slightly longer wing lengths. The techniques used highlighted the importance of selection criteria, access to natural growth curves to infer feeding regimes, nutritionally rich diets, and strict hygiene protocols. Our trial provides a knowledge base for future translocations and the establishment of new kuaka Whenua Hou colonies.

Tuhinga whakarāpopoto: He momo tata korehāhā te kuaka o Whenua Hou (Pelecanoides georgicus whenuahouensis), he momo ōi e whai rua hei kōhanga, kua mau ki te whakatipu ki ngā tāhuahua kopī o mua o Whenua Hou. Ko te whakarauora o tēnei momo kua whakanguengue i ngā āhuatanga whakaraerae e mau tonu pērā i te pokanga rama, ā rātou ake pakanga ki a rātou me te hurihuri o te āhuarangi, tae noa atu ki te horonga whenua o te pūrei kōhanga marore nō te marangai, ā nō reira, ka whai hua te kuaka Whenua Hou i te whakatūtanga atu o tētahi taiwhenua hou mā te nukunuku kōhanga. Engari, me whakatipu ngā pīrere ki te ringa ki te wāhi e tū ai te kōhanga hou kia ea ai te nuku kōhanga, ā, kia tautuhi anō tā rātou hiahia ki te hoki atu ki te kāinga i whakatipuria kētia rātou. I āta mārama mātou ki te whakamātautau o te whakatipu ā-ringa me te nukunuku kōhanga o te kuaka Whenua Hou kia whakarite ai ki te nukunukunga tūturu e haere ake nei. I nuku kia ngahuru ngā pīpī kuaka Whenua Hou mai i ngā rua i whānau mai ai rātou ki ētahi kōhanga hanga i whakatūria ki muri i te taiwhenua matua, ā, i whakatipuria rātou ki te ringa ki ētahi kai ake o te hārini penupenu. I whai huruhuru pai ngā pīpī katoa, ā, ehara i te rerekē te taumaha o ēnei pīpī i ērā i whakatipuria ki ō rātou ake kōhanga, engari he paku roa ake ngā parirau. I whakamiramira atu ngā tū-āhua i whakamahia i te hiranga o ngā paearu whiri, te whai wāhitanga ki ngā pikinga whakatipu māori kia whakapae tika ai te tikanga whāngai, te whiringa o te kai taioranga me ngā tikanga akuaku mārō. Ka noho tā mātou whakamātautau hei tūāpapa mātauranga ki ngā nukunukunga kōhanga e haere ake nei, me te whakatūtanga o ētahi taiwhenua hou mō ngā kuaka Whenua Hou.

Abstract: House mice (Mus musculus) have proven to be the most difficult introduced mammal to eradicate from (and keep out of) New Zealand reserves and sanctuaries. Partly as a consequence of this, little is known about how bird communities respond to mouse eradication. Mice were successfully eradicated from 217 ha Mana Island Scientific Reserve, near Wellington, in 1989–90. Five-minute bird count surveys undertaken in spring and autumn before and after mouse eradication revealed that 13 of 22 species were recorded significantly more often after mouse eradication, and just two species were recorded significantly less often following the eradication (and each of these in one only of the two seasons that were compared). Four species had no significant change, and three species showed mixed responses between the two seasons. While the overall pattern was of increased relative bird abundance after mouse eradication, there is limited information on why individual bird species increased during the study period, and whether this was a consequence of mouse eradication. Bird count data revealed that insectivorous passerines may have benefited the most from mouse eradication on Mana Island, suggesting that competition for invertebrate prey was the main impact that mice had on the birds of the island. The use of anticoagulant rodenticides to eradicate mice from Mana Island had little detectable impact on populations of the island’s birds.

Abstract: Male and female adult Floreana mockingbird (Mimus trifasciatus) have monomorphic plumage features that make them impossible to sex in the field. In this study, we use discriminant function analysis (DFA), a widely used technique, to assess the best measures to determine sex. We measured six morphological characteristics (mass, beak depth, beak width, tarsus length, wing length, and head-beak length) for birds of known sex (determined by molecular techniques) from the two extant populations of M. trifasciatus on Champion and Gardner islets, within the Galápagos archipelago. Using a coefficient of sexual dimorphism, we found that males are significantly larger than females in three of the variables. Discriminant functions using wing length and a combination of wing length + mass, and wing length + tarsus length could classify birds with a 98% level of accuracy. Furthermore, we were able to estimate a robust cut-off point to determine the sex of individuals in the field through a decision tree, using only wing length as morphological variable. Fast and accurate sexing of the bird based on one variable will reduce handling times and minimise stress for captured birds.