Previous reproductive success and environmental variation influence nest-site fidelity of a subarctic-nesting goose.

Abstract

Nest-site fidelity is a common strategy in birds and is believed to be adaptive due to familiarity with local conditions. Returning to previously successful nest sites (i.e., the win-stay lose-switch strategy) may be beneficial when habitat quality is spatially variable and temporally predictable; however, changes in environmental conditions may constrain dispersal decisions despite previous reproductive success. We used long-term (2000-2017) capture-mark-reencounter data and hierarchical models to examine fine-scale nest-site fidelity of emperor geese (Anser canagicus) on the Yukon-Kuskokwim Delta in Alaska. Our objectives were to quantify nest-site dispersal distances, determine whether dispersal distance is affected by previous nest fate, spring timing, or major flooding events on the study area, and determine if nest-site fidelity is adaptive in that it leads to higher nest survival. Consistent with the win-stay lose-switch strategy, expected dispersal distance for individuals that failed their nesting attempt in the previous year was greater (207.7 m, 95% HPDI: 151.1-272.7) than expected dispersal distance for individuals that nested successfully in the previous year (125.5 m, 95% HPDI: 107.1-144.9). Expected dispersal distance was slightly greater following years of major flooding events for individuals that nested successfully, although this pattern was not observed for individuals that failed their nesting attempt. We did not find evidence that expected dispersal distance was influenced by spring timing. Importantly, dispersal distance was positively related to daily survival probability of emperor goose nests for individuals that failed their previous nesting attempt, suggesting an adaptive benefit to the win-stay lose-switch strategy. Our results highlight the importance of previous experience and environmental variation for informing dispersal decisions of a long-lived goose species. However, it is unclear if dispersal decisions based on previous experience will continue to be adaptive as variability in environmental conditions increases in northern breeding areas.