The effects of fluctuating food availability on breeding arctic terns (Sterna paradisaea)

Determining seabirds reproductive patterns requires an analysis of food availability and its effects on reproduction costs. Continuous poor recruitment of fish spawned and a decline in spawning-stock biomass led to the reduction of sandeels in Shetland waters between 1985 and 1990. A 55% decline in arctic terns breeding was observed between 1981 and 1989. Bird responses to variations in sandeel abundance at Shetland from 1990 and 1994 were analyzed and results revealed a significant relationship between tern productivity and food supply.