Attachment

Download

Ten white-headed petrels (Pterodroma lessonii) from Adams Island, Auckland Islands, were tracked during 2011–14 using miniature geolocators, in the first study to examine the at-sea movements and key foraging areas of this pelagic seabird. Data revealed extensive migrations west to South Africa and east into the central South Pacific Ocean. The birds returned to colonies Aug–Oct. Median departure on pre-laying exodus was 24 Sep. Birds were away for up to 77 days during pre-laying and moved west towards the Indian Ocean. Laying occurred 24 Nov–10 Dec. The first major incubation shifts by males and females were c. 19 days in duration. The maximum foraging range during incubation was 5,230 km from the colony, the most distant recorded by any seabird during this breeding stage. After eggs hatched in January, some birds foraged off Antarctica in sea temperatures down to –1°C. Birds spent the inter-breeding period in disjunct areas (off South Africa, south of Australia, Tasman Sea, and South Pacific Ocean). This study revealed an unusual courtship behaviour not recorded previously in other seabird species. Females returned from distant oceans to spend just a few days ashore in the pre-laying period before leaving the breeding site until the following spring. The males also skipped breeding at the same time as their mates, but returned earlier in the season. The new knowledge gained about the breeding activity of this species will assist with future population assessments.