The diet and feeding ecology of breeding KittiwakesRissa tridactyla

Abstract

An investigation of the effects of chick growth and brood size on the activity patterns of parent kittiwakes showed that the rate of provisioning to the brood was constrained by factors other than the chick''s requirements. Feeding frequency increased from 3.1 to only 3.7 feeds/brood per day between the beginning and end of the nestling period and was unaffected by brood size. The rate of provisioning was not adequate for broods of 3 chicks; asynchronous hatching followed by sibling aggression resulted in the 1st-hatched chicks receiving an unequal share of the food and the deaths, through starvation, of many of the younger chicks. The parents of larger broods attempted to increase their chick-feeding capacity by temporarily deserting their broods overnight, so that both parents could search for food simultaneously. The amount of time needed to obtain an economic food load limits the rate of provisioning to the chicks.