HIGHLY PATHOGENIC AVIAN INFLUENZA VIRUS RESULTED IN UNPRECEDENTED REPRODUCTIVE FAILURE AND MOVEMENT BEHAVIOUR BY NORTHERN GANNETS.

In 2022, highly pathogenic avian influenza (HPAI) virus resulted in mass mortality throughout seabird colonies in the North Atlantic Ocean. While mortalities and transmission of the virus are being documented, other effects are less understood. We documented nest abandonment and unprecedented reproductive failure by Northern Gannets Morus bassanus at Cape St. Mary's, Newfoundland and Labrador, Canada, the species' southernmost colony. Reproductive success in 2022 was the lowest on record at 17%, which was likely a result of adults abandoning the nest and succumbing to avian influenza virus (AIV) infection. Following the AIV outbreak at Cape St. Mary's, we also documented extremely long foraging trips, including the second known instance of inter-colony movement by an adult Northern Gannet, who embarked on two trips to the gannet colony on Baccalieu Island. This inter-colony movement represents a possible means of viral transmission between colonies. The effects of HPAI may have been exacerbated as a result of heat stress during a marine heatwave, which coincided with the major outbreak at this colony. As this HPAI virus could continue to circulate in seabirds, ongoing monitoring of mortality and other indirect effects of AIV outbreaks are needed to inform future impacts. [ABSTRACT FROM AUTHOR]