Do different petrel species feed their chick differently?

摘要

Fulmarine petrels are seabirds abundantly present in Antarctic waters, and breed in high numbers in the Antarctic region. The main adaptations for a reproductive life at high latitudes are their contracted breeding cycles and a high frequency of feeding the chick. Next to the feeding frequency, the amount of food brought to the chick is important for chick growth. On Ardery Island (66 degree S 110 degree E), we compared the chick provisioning strategies of the closely related Antarctic Petrel (Thalassoica antarctica) and Southern Fulmar (Fulmarus glacialoides) by using an automated weighing system with artificial nests. Although both species have a similar diet, Antarctic Petrels continued a pattern of long foraging trips even in the chick period when the extent of sea-ice was minimal and allowed nearby feeding. Fulmars made much shorter trips delivering much more meals to their chicks. The sizes of meals delivered by both species were similar. Despite lower feeding frequency but similar meal sizes, the growth of Antarctic Petrel chicks was comparable to that of Southern Fulmars, and so was the time needed until fledging. We discuss how Antarctic Petrel chicks are able to achieve higher growth efficiency per delivered meal. Differences in wing morphology of Antarctic Petrels and Southern Fulmars may explain their different foraging techniques and duration of foraging trips.