A two-fold increase in migration distance does not have breeding consequences in a long-distance migratory seabird with high flight costs

Whether variation of winter migration distance among individuals within a population has consequences on their reproductive performance has rarely been assessed. Using individual global location sensor-tracking, we determined variation in migration distance, and its breeding consequences, in a Svalbard colony of the little auk Alle alle , a high-Arctic seabird with high flight costs. We found 2 distinct wintering quarters (north of Iceland and SW Greenland) implying a 2-fold difference in migration distance (1500 vs. 3100 km on average from the colony). This migration route from Svalbard to Greenland is among the longest recorded distances for an alcid species. Birds travelling a longer distance were more likely to be females and smaller, but more importantly, migration strategy had no apparent effect on reproductive performance (either timing or success). Our results contradict predictive studies which suggested that the establishment of migration routes to different winter destinations may be limited by the energetic constraints of flight. Our results show that a longer migration route does not necessarily have carry-over effects on subsequent reproduction.