The Northern Gannet is the largest breeding seabird in the North Atlantic Ocean. This species was a focus of this study because it is abundant in the mid-Atlantic in winter, during non-breeding periods. Previous studies conducted in Europe have also indicated a range of possible effects of offshore wind development on Northern Gannets, including collision mortality and displacement.
Download Mid-Atlantic Wildlife Studies: Distribution and Abundance of Wildlife along the Eastern Seaboard 2012-2014. This 32-page summary publication explores aspects of the mid-Atlantic ecosystem; describes our survey and analytical approaches; and presents a range of results, featuring several case studies on specific species or phenomena.
The Executive Summary for the technical report is also available here.
Northern Gannets are long-lived and exhibit high adult survival. They begin breeding around five years of age. Females lay one egg per year; both parents raise the chick. In the Western Hemisphere, Northern Gannets breed at six colonies in southeastern Canada—three in the Gulf of St. Lawrence, Quebec, and three off the eastern and southern coasts of Newfoundland. They winter in Atlantic shelf waters from the Mid-Atlantic Bight to the northern Gulf of Mexico.
The Northern Gannet has a Conservation Status of Least Concern from the International Union for the Conservation of Nature, due to its relatively large population size and exceptionally large range. The North American breeding population, 27% of the global population, has experienced a healthy growth rate of 4.4% per year since 1984, although that appears to have slowed in recent years.
Northern Gannet migration was highly asynchronous and widely dispersed across the continental shelf; they generally moved up the coast in March-April, often pausing in large bays. Birds typically left breeding colonies in September and either followed the coast or the shelf edge southward, arriving in the wintering area in November-December. Individuals roamed widely through the area in winter, showing low site fidelity.
Northern Gannets were most consistently observed in nearshore waters in our surveys, although telemetry data showed them regularly ranging as far as 50 km onto the continental shelf. The birds generally used habitat characterized by highly productive, shallower waters, with lower sea surface salinities, especially areas closer to shore and over fine sandy substrate.
Northern Gannets were observed from boat-based and digital aerial surveys year round, with the highest numbers observed between September and April.
Satellite tracked Northern Gannets first arrived in the mid-Atlantic in August, with peak arrival time around November, and they departed between February and May. A time variant kernel density model of satellite telemetry data was developed to improve our understanding of the species’ use of the landscape through time. The movement video generated from this model is shown here.
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