The Effects of Fluctuating Food Availability on Breeding Arctic Terns (Sterna paradisaea)

Reproduction is a costly process that involves an investment of effort that candecrease parental condition and survival (Partridge 1989, Stearns 1992).In long-lived iteroparous species such as seabirds, reproductive costs produce a tradeoff in energy allocation between current and future breeding attempts (Clutton-Brock 1984), and the breeding effort should be adjusted to maximize lifetime reproductive success.Food availability can have substantial effects on the relative costs of reproduction and thus may be an important factor in determining reproductive strategies in seabirds (Boekelheide and Ainley 1989, Sydeman et al. 1991, Pons and Migot 1995).Cairns (1987) hypothesized that during periods of reduced food supply, seabirds should increase foraging effort in order to buffer the effects of food scarcity on breeding performance.Further reductions in food may result in parents being unable to increase foraging effort without incurring excessive costs, resuiting in a decline in reproductive success (Monaghan et al. 1989, 1992).