IMPACT OF SNOW AND FOOD CONDITIONS ON THE REPRODUCTIVE-PERFORMANCE OFBARNACLE GEESE BRANTA-LEUCOPSIS

This study examined the availability of food for Barnacle Geese breedi ng on Spitsbergen in relation to the snowmelt, their feeding activitie s and food intake in relation to phenological events, and their reprod uctive performance. The food intake rate increased gradually throughou t spring, concomitant with an increase in the density and quality of t he food on offer. The timing of incubation was ultimately controlled b y the availability of food throughout summer, being an evolutionary tr ade-off between a late start (favourable foraging conditions during th e egg stage, which enhanced the probability of successfully hatching t he eggs), and an early start (resulting in a high survival rate of the off-spring). A necessary delay of incubation in late snowmelt seasons affected, in order of importance, nest success, brood size at hatchin g, and the proportion of pairs that initiated breeding.