Distribution

Fig. 1. Distribution of the Hooded Merganser.

The Americas

Breeding Range

Breeds throughout the east and Pacific Northwest (Fig. 1); most common in forested regions around the Great Lakes. Northern breeding limit in Canada poorly defined (Godfrey 1986). In Ontario, breeding commonly occurs only in southern regions, occasionally to 50°N, but possibly as far north as the Albany River (Peck and James 1983). In the west, breeds south of Queen Charlotte Is.; one exceptional record of a female and brood from Innoko National Wildlife Refuge in central Alaska (Bellrose 1976); increased observations of pairs in early spring in the Northwest Territories might represent a range expansion of breeding populations (Fournier and Hines 1996).

Breeds from sea level to 1,180 m in British Columbia (Campbell et al. 1990). N. Dakota the only U.S. plains state with sizable numbers (e.g., Doty et al. 1984, LHF); scattered breeding occurs in s.-central Montana (J. Hansen pers. comm.), Oklahoma (Clover 1981, LHF), Nebraska (LHF), S. Dakota (LHF, Smith 1981), and possibly in many mountainous regions in the western U.S. as far south as New Mexico (e.g., Hubbard 1984). Recorded as far south as n. Florida (Fla. Game and Fresh Water Fish Comm. unpubl. data). Populations in the south more localized but often common where they occur (LHF).

Winter Range

Primary winter areas include the se. U.S. for eastern birds and the nw. Pacific, north of California, for western populations, but birds occur throughout most of the s. U.S. north of Mexico (Bellrose 1976, Root 1988). Generally restricted to areas where the average minimum Jan temperature does not drop much below -7°C (Root 1988). Jan winter inventories indicate 61% winter in the Mississippi Flyway, where concentrations occur in the Mississippi Alluvial Valley and reach peak densities in w.-central Mississippi (Bellrose 1976, Root 1988); 22% winter in the Atlantic Flyway, with concentrations occurring south of Maryland primarily along coastal waters. Almost all of the 6% wintering in the Central Flyway occur in ne. Texas; 11% winter in the Pacific Flyway. Recorded as a rare winter visitor to Baja California, Veracruz, Distrito Federal, and Coahuila in Mexico (Blake 1953, Garza-de-Leon 1987), and Cuba, Puerto Rico, Bahamas, St. Croix, and Martinique in the Caribbean (Bond 1985). Vagrants recorded twice in Hawaii (Burger 1981) and once on the Yucatan peninsula of Mexico (Ornat et al. 1989).

Outside The Americas

Only merganser indigenous to North America. Accidental in the British Isles (≥ 6 records, Dec–Jan); also West Germany, Scandinavia, Iceland, although reports complicated by possibility of escapes from collections in Europe (Bentz 1987, Alström and Colston 1991, Petursson et al. 1991).

Historical Changes

From early accounts it seems almost certain this species nested throughout the e. U.S. where suitable habitat existed; also throughout all mountainous states in the west. However, habitat alterations occurred so long ago in many parts of the east and northeast, the birds already were scarce or eliminated as breeders by Audubon’s time (Phillips 1926). Phillips (1926) further suggests that eastern populations fell precipitously in the forty years prior to 1925, primarily due to logging of old forests which eliminated nesting cavities, and the birds unwary nature around hunters. Today breeding birds occur throughout most of their ancestral range, though populations are reduced and localized; recent reports suggest growing populations in portions of the northeast (Heusmann et al. 2000), and expansions in California (Pandolfino et al. 2006) and possibly the Northwest Territories (Fournier and Hines 1996).

Fossil History

Late Pleistocene (0.6 Megannum [Ma]) and Holocene (10,000 yr) records for this species are known from several states including: Florida, Illinois, Kansas, Oklahoma, S. Dakota, Tennessee, Utah, and Virginia (Brodkorb 1964: 247; Ligon 1965: 137; Parmalee 1967: 130; Guilday et al. 1977: 28; Parmalee 1977: 195; Guilday et al. 1978: 14; Campbell 1980: 122; Parmalee 1980: 240).

The late Pleistocene duck Querquedula floridiana Shufeldt (1917: 36) from Vero, FL was re-examined by Wetmore (1955: 189) and the species was reassigned to Lophodytes . Brodkorb (1964: 247) without explanation included L. floridiana under the L. cucullatus record.