Abstract Title
HOPE FOR THE FUTURE: NORTHERN GANNETS DEMONSTRATE DEMOGRAPHIC RESILIENCY FOLLOWING MASS MORTALITY DUE TO HPAI (H5N1)
Abstract
Northern Gannets (Morus bassanus) were among the most affected species during the 2022 global outbreak of highly pathogenic avian influenza (HPAI H5N1). Adult mortality was extensive at the Northern Gannet’s southernmost colony, Cape St. Mary’s, Newfoundland and Labrador, Canada, which resulted in the colony’s lowest reproductive success on record (17%). The magnitude of the event raised concerns over the ability of the population to recover. We investigated breeding phenology, colony attendance, reproductive success, and population demographics at Cape St. Mary’s during the breeding season following the HPAI outbreak (2023). Throughout the 2023 season, empty sites where gannets previously nested were evident and many sub-adult gannets attended the colony. Despite a moderate marine heatwave, the high mortality of the previous year, and continuing low-levels of HPAI-linked mortality in 2023, reproductive success was 73%, which is higher than the long-term average before the HPAI outbreak (61%) and higher than the level (65%) needed for population sustainability and growth. We hypothesize that surviving breeding adults were the most fit parents, and that lower breeding densities resulting from the mass mortality event may have reduced nest-site and foraging competition. These results demonstrate that the colony likely has the capacity to rebound from observed population losses.
Co-Author(s)
Rebecca Wiseman - Memorial University of Newfoundland
Noah Careen - Memorial University of Newfoundland
Sydney Collins - Memorial University of Newfoundland
Kyle d'Entremont - Memorial University of Newfoundland
William Montevecchi - Memorial University of Newfoundland
Abstract Category
Notable outbreaks, field and molecular epidemiology, and surveillance in wild birds