A study on the biology of the kittiwake (rissa tridactyla)

Abstract

The attendance and behaviour of successfully breeding kittiwake adults and their chicks at the breeding site was monitored both by a time-lapse filming technique and spot observations over 3 successive breeding seasons. The orientation of adults at the site was shown to reflect the changing requirements of protection for eggs and brood through the cycle. The attendance pattern similarly reflected variation according to the requirements of pair-bonds, egg and chick-care and although on average adults shared the duties, in particular cases pairs could take unequal shares. The early stages were co-ordinated and consistent but after early chick-care individual attendance patterns lost these properties due to the avoidance of the brood so that individual broods received individual patterns of guarding. Throughout the rest of the cycle adults increasingly avoided their broods as these developed. The form and amount of avoidance depended upon the restrictions of the nest site, brood size and the 'quality' of the adult. While chicks were not killed by non-breeding adults visiting unguarded nest sites, their fledging patterns may well have been disrupted at the time when waterproofing and independent foraging skills were least developed. Those chicks left unattended relatively early were over-represented in the substantial mortality (mainly by drowning) during the fledging stage. Adult behaviour showed cliff-nesting adaptations and was similar in form in all individuals. Avoidance of the attention of well- grown chicks was pronounced. Chick behaviour (itself not affected by whichever adult of the pair attended) showed a progressive independance of the attention of the adults, although the chicks were not freely mobile over the ledge until after the first flight. Chicks' begging interactions, responsible for the avoidance by the parents, were not simply related to the amount of feeding. The possible consequences of this are discussed.