Movements and daily activity patterns of Black-tailed Gull fledglings from fledging to wintering

Abstract

Understanding the behavior and movements of fledglings after leaving the nest is crucial for assessing their survival rate and the long-term viability of populations. In this study, we tracked Black-tailed Gull fledglings from Kabushima Island (Kabushima), Japan, using biologging devices that recorded GPS locations and overall dynamic body acceleration. All fledglings that survived for up to nine months after leaving the island traveled over 800 km and did not return to the island before at least the following breeding season. Additionally, they were predominantly active during the daytime, in contrast to breeding adults, which have been reported to be active during both day and night. These differences may reflect the juveniles' limited flight or foraging capabilities, or the ecological demands on breeding adults.