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

This study examined the availability of food for Barnacle Geese breeding on Spitsbergen in relation to the snowmelt, their feeding activities and food intake in relation to phenological events, and their reproductive performance. The food intake rate increased gradually throughout spring, concomitant with an increase in the density and quality of the food on offer. The timing of incubation was ultimately controlled by the availability of food throughout summer, being an evolutionary trade-off between a late start (favourable foraging conditions during the egg stage, which enhanced the probability of successfully hatching the 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 hatching, and the proportion of pairs that initiated breeding.