The northern gannets of North America breed in six large colonies along the Gulf of St. Lawrence and the coast of Newfoundland. Adults arrive at those rocky headlands by early April and depart by early October, wintering at sea along the coastal shelf, from Maine to Mexico. Non-breeding juveniles spend their first three years at sea before returning to their ancestral breeding sites.
Prior to the Deep Horizon disaster, in April of 2010, it was assumed that only a small minority of North American gannets wintered in the Gulf of Mexico; this assumption was based on the results of past tagging studies. However, a large percentage of the oiled birds found along the Gulf Coast proved to be northern gannets, primarily juveniles; the predominance of juveniles reflected the time of year of the disaster, when most adults had returned to Canadian breeding grounds. In fact, more recent studies, using GPS, have revealed that 25% of North American gannets winter in the Gulf of Mexico at some point in their lives.
On this crisp, breezy Thanksgiving Day, we saw more gannets off the coast of Longboat Key, Florida, than on any visit in the past. Joining brown pelicans, double-crested cormorants, laughing gulls and a host of tern species, the gannets (both adults and juveniles) dove for fish as close as 100 yards from the beach. Diving from 100 feet or more above the surface, their spear-like entry exceeds the less graceful plummet of brown pelicans in both speed and precision. Indeed, we were thankful to have witnessed their spectacular display.
