Seasonal movements and foraging activity of black-winged petrel Pterodroma nigripennis from three New Zealand colonies
Matt Rayner1, Chris Gaskin2, Graeme Taylor3
1Auckland Museum, Private Bag 92018, Auckland, 1141, New Zealand. mrayner@aucklandmuseum.com
2Northern New Zealand Seabird Trust, 400 Leigh Road, RD5, Warkworth 0985, New Zealand. chris.gaskin@xtra.co.nz
3Department of Conservation, Conservation House, 18-32 Manners Street, Wellington 6011, New Zealand. gtaylor@doc.govt.nz
Black-winged petrels (Pterodroma nigripennis) were tracked from Rangitahua (Raoul Island, The Kermadecs, n = 11), Burgess Island (The Mokohinaus, n = 5) and Rangitira (South East Island, Rekohu, The Chatham Islands, n = 6) between 2009 and 2010 using miniature geolocators in the first study to examine inter-seasonal movements and activity in this species. During the breeding season (November-April) birds from all three colonies foraged extensively in waters North and East of New Zealand with particular use of the subtropical convergence zone east of the Chatham Islands with maximum foraging ranges of up to 4000 km. Extensive migrations by this species occurred between April and November with migration routes shared between birds from different colonies. Atypical of other Pterodroma to date birds did not occupy a tight non-breeding core distribution rather migrated rapidly North-Northeast to the eastern equatorial tropical Pacific followed by more gradual movements North-West June – October reaching 30 degrees North in a broad longitudinal band west of Hawaii over 9000 km from the breeding colony. A South-West pre breeding migration was conducted over approximately 30 days. Activity data from the geolocators indicate that outside the breeding season black-winged petrels show strong nocturnal foraging behaviour with stable isotope data suggesting a mixed diet of vertically migrating zooplankton and fish prey. Comparisons of these data with work on other Pterodroma petrels will be discussed.