Flesh-footed shearwater population monitoring 2019/20
Published:
August 2020Download the publication
Summary
This report covers the findings from the second of three years’ flesh-footed shearwater (Puffinus carneipes) research. We report on the ongoing population monitoring of flesh-footed shearwaters on Ohinau and Lady Alice Islands and the results of GPS tracking of breeding birds from both islands.
During the 2019/20 breeding seasons we monitored 274 and 288 study burrows on Ohinau and Lady Alice Islands respectively. A total of 216 study burrows on Ohinau Island were breeding and we were able to identify 408 of the 432 (94%) partners occupying these study burrows. On Lady Alice Island, 202 study burrows were breeding and 358 of 404 (89%) of partners occupying these study burrows were identified. We were unable to determine breeding success for the 2019/20 season but the rate of failure during incubation in January was similar to the 2018/19 season.
Breeding flesh-footed shearwaters were tracked simultaneously on Ohinau and Lady Alice Islands during the incubation and chick-rearing stages. On Ohinau Island, GPS devices were deployed on 26 individuals during incubation and 27 individuals during chick-rearing and this yielded 21 tracks and 50 tracks respectively. On Lady Alice Island, GPS devices were deployed on 29 individuals during incubation and 34 individuals during chick-rearing and this yielded 20 tracks and 55 tracks respectively.
The average length of incubation foraging trips was 11.8 days and 4,665 km for Ohinau Island birds and 16.6 days and 4,734 km for Lady Alice Island birds. Lady Alice birds undertook significantly longer trips in respect to duration. The average length of foraging trips during chick-rearing was 3.1 days and 1,205 km for Ohinau birds, and was 4.8 days and 1,536 km for Lady Alice birds. There was considerable variation in all aspects of foraging trips during chick-rearing which is likely due to a dual-foraging strategy.
There was considerable overlap of foraging areas between Ohinau and Lady Alice birds indicating that birds from different populations mix at sea during the breeding season. All birds from Ohinau Island foraged either down the East Coast of the North Island or out towards the Louisville Ridge. During incubation, nearly half of Lady Alice birds foraged in the same locations while the remaining birds foraged inshore off the West Coast of the North Island or offshore in the Tasman Sea. During chickrearing, areas closer to each of the colonies had greater importance but birds still utilised some of the more distant foraging locations identified during incubation in order to maintain their own body weight and condition.
Publication information
Crowe, P. 2020. Flesh-footed shearwater population monitoring and at-sea distribution: 2019/20 season. Report prepared by Wildlife Management International Limited for the New Zealand Department of Conservation, Wellington. 39 p.
Contact
Conservation Services Programme
Department of Conservation
PO Box 10-420
Wellington 6143
Email: csp@doc.govt.nz