Meeting Abstract
In migratory songbirds, behavior and habitat use during arrival and breeding has been studied intensively for decades. However, bird activities at the termination of the breeding season are less well understood. During the post-breeding period, offspring become independent and adults shift time away from provisioning young and towards self maintenance as they enter molt and prepare for migration. Additionally, as the season progresses abundance and distribution of food resources change. While terrestrial arthropod biomass peaks in early July at the time that offspring are fledging, berries ripen and aquatic arthropod biomass peaks in August which coincides with molt. Energetic demands and increased predation risk associated with molt, as well as shifts in food resources, may force individuals to alter movement patterns on the landscape. To investigate habitat use, we attached radio-transmitters to Gambel’s White-crowned sparrows (Zonotrichia leucophrys gambelii) with known nests at the termination of the breeding season at Toolik Lake Research Station on the North Slope of Alaska. Adults were tracked using both automated and handheld receivers until departure for fall migration. Results show that most birds stayed within 100-200 meters of the nest until departure. In addition, predation rates were highest during the last week of July to first week in August when molt is most intense. Given inter-annual variation in weather and predator-prey dynamics on the tundra, additional years of data collection would be illuminating in this system
