Distribution

Cold, temperate waters overlying continental shelves, from arctic fringe in North Atlantic to sub-tropics on east and west sides of the Atlantic; not a bird of deep ocean waters. Breeds in dense colonies on remote and relatively inaccessible coastal cliffs, stacks, and islands or less frequently on precipitous inaccessible cliffs of mainland, within foraging distance of its principal prey, herring (Clupea harengus) and mackerel. Adult breeders may range up to 500 km from colonies during foraging, and nonbreeders even farther (Nelson 1978a, Montevecchi et al. 1980); less gregarious, more widely dispersed southward during nonbreeding season. Northern limits of breeding range probably fixed, principally, by shortness of breeding season (as distribution of herring extend north of northernmost colonies), and southerly limit by distribution of important shoaling prey species (Cramp and Simmons 1977, Nelson 1978a).

Breeding Range

Figure 1 . Breeds in 6 major colonies (a single pair was reported breeding in 1999 on Whitehorse I., New Brunswick, a new site; Corrigan and Diamond 2001) on relatively inaccessible cliffs, stacks, and islands; present at breeding sites Mar–Nov (Montevecchi et al. 1980, Am. Ornithol. Union 1998, J. Chardine pers. comm.). Of the 6 breeding colonies in North America, 3 occur in Gulf of St. Lawrence: (1) Bonaventure I., Québec, 3.6 km offshore from Gaspé Peninsula at 48°30’N × 64°09’W; (2) Gullcliff Bay, Québec, on southeastern tip of Anticosti I. at 49°09’N × 61°42’W; and (3) Bird Rocks, Québec, northernmost islands of the Magdalen Is. Archipelago at 47°50’N × 61°09’W. Also 3 on the Atlantic coast of Newfoundland: (1) Cape St. Mary’s, Newfoundland, on mainland cliffs and a stack separated by a narrow 15- to 20-m ravine from southwestern tip of Avalon Peninsula at 46°50’N × 54°12’W; (2) Baccalieu I., Newfoundland, just off northeastern tip of Avalon Peninsula between Trinity and Conception Bays at 48°07’N × 52°47’W; and (3) Funk I., Newfoundland, 50 km northeast of Cape Freels at 49°46’N × 53°11’W (Nettleship 1976, Montevecchi et al. 1980, Nettleship and Chapdelaine 1988, Am. Ornithol. Union 1998). Northern extent of breeding colonies in w. North Atlantic appears to be limited by suitable primary prey (i.e., large-bodied, surface schooling, moderately warm-water fish and squid), and by distance from breeding site gannets must travel to locate these prey (Kirkham et al. 1985).

During breeding season, adult breeders and subadult nonbreeders range extensively within waters of North Atlantic, having been reported from Bay of Fundy (Nelson 1978a), off Labrador coast (Todd 1963), sw. Greenland (Salomonsen 1967, Nelson 1978a), regularly in Strait of Belle Isle (Kirkham et al. 1985), and throughout Gulf of St. Lawrence (Chapdelaine 1996).

Winter Range

Figure 1 . At sea; largely within waters overlying continental shelf from New England south along Atlantic Coast to Florida, and west along Gulf Coast to Texas and ne. Mexico. Adults tend to remain farther north in continental-shelf waters slightly southwest of breeding areas; large concentrations often observed off New England coast and near continental slope off coast of Massachusetts (Veit and Petersen 1993); subadults and especially fledglings generally travel farther south (Palmer 1976, Nelson 1978a). Gannets common in mid- to late fall and early spring in Long Island Sound and off Montauk Point, NY (Askildsen 1998); common winter resident off New Jersey coast (Walsh et al. 1999) and accidental in lower Delaware River of Pennsylvania midfall through early winter, and early spring (McWilliams and Brauning 2000); common transient and uncommon winter resident offshore and in lower Chesapeake Bay of Virginia (Kain 1987) and a common winter resident along Carolina coast, especially off Outer Banks (Potter et al. 1980). In Florida, common to uncommon winter resident along upper Atlantic Coast, coast of s. Florida, and on Gulf Coast (Stevenson and Anderson 1994); in Gulf of Mexico, uncommon in pelagic waters off coasts of Alabama, Mississippi (Turcotte and Watts 1999), Louisiana (Lowery 1974), and Texas (Rappole and Blacklock 1994), and rare to uncommon off northeast coast of Mexico (Howell and Webb 1995). Rare to uncommon vagrant in Bahamas and off Cuba (Wallace and Fillman 1994, Raffaele et al. 1998, Brewer et al. in press) and Bermuda (Amos 1991).

Other Records

Casual during winter southwest of breeding range inland in New England (Am. Ornithol. Union 1998), St. Lawrence Valley (Chapdelaine 1996), Great Lakes west to Michigan, Indiana, and Ohio (Nelson 1978a, Peterjohn 1989). Accidental in Illinois, Kentucky, and Tennessee (Braun 1988); Tamaulipas and Veracruz, Mexico (Howell and Webb 1995); and Bahama Is. (Am. Ornithol. Union 1998, Raffaele et al. 1998).

Breeds in Western Palearctic within limits of continental shelf of North Atlantic, over a range of 48° latitude, from Rouzic, Brittany, France, to Syltefjord, Norway. Breeding range includes 32 established colonies from nw. France, British Isles, Iceland, Faeroe Is., and Norway (Nelson 2002). Winters at sea from south and east of Russia, Scandinavia, Baltic Sea, throughout Mediterranean Sea, and along Atlantic coast to nw. Africa, and casually to Cape Verde Is. (Cramp and Simmons 1977; Nelson 1978a, 2002; Am. Ornithol. Union 1998).

Appears to be little exchange between Old- and New-World birds; of >13,000 Northern Gannets banded in Canadian colonies, 1921–1995, only 3 re-turns from e. Atlantic waters: an immature banded at Bonaventure I., Québec, from Cabo de Penas, Spain; an adult bird banded at Funk I., Newfoundland, from Flatey I., Iceland; and a chick banded at Funk I., from south of Casablanca, Morocco; no recovered bands in North America of birds banded in e. Atlantic colonies (Brewer et al. in press).

Colonies generally stable; occasionally new colonies initiated, as populations in existing colonies increase, and birds prospect for potential breeding sites (Gould 1974, Montevecchi and Wells 1980, Corrigan and Diamond 2001). In Québec, until 1857–1959, Northern Gannets bred in Perroquet Is., Mingans (Nelson 1978a), and at the time of Jacques Cartier’s voyage to Canada in 1534, Bird Rocks gannetry apparently consisted of 3 separate islands. Since then, 1 island has been lost to erosion and the remaining 2, Great Bird and North Bird Rocks, have been considerably reduced in size (Chapdelaine 1996). Gannets formerly occupied colonies on islands in the Wolves Is. Archipelago in sw. Bay of Fundy, New Brunswick (Corrigan and Diamond 2001); Gannet Rock, Grand Manan Archipelago, New Brunswick, until a lighthouse was built in mid-1800s (Nelson 1978a); and at Gannet Rock, Yarmouth, Nova Scotia, until mid-1800s, when persecution by local fishermen caused colony’s extinction (Nelson 1978a).

Main evolutionary radiation of the Sulidae appears to have occurred during the Miocene (15–25 million years before present), when both genera, Sula and Morus, could already be distinguished (though not yet meriting true generic status; Nelson 1978a). Earliest fossil gannets occur in the middle Miocene, slightly later than earliest Sula species, in the Bone Valley formation, California. A fossil (Morus reyanus) similar to the modern gannet occurs in the upper Pleistocene on the Pacific coast of North America, where no gannets occur today (Nelson 1978a).