Razorbill Habitat Model
go to: USFWS Gulf of Maine Watershed Habitat Analysis
go to: Species Table

Draft Date:
November 2002

Species:
Razorbill, Alca torda

Use of Study Area Resources:
Reproduction, wintering.  "...breeds from Maine and western Greenland east to Iceland, the Faeroes, and the British Isles, and south to northern France... " The western Atlantic population is "...mainly confined to eastern Canada and the northern part of New England... primarily southern Labrador and Gulf of St. Lawrence...   Western Atlantic birds winter at sea from the Grands Banks off Newfoundland south, regularly in small numbers, to Maryland and Virginia, with a concentration off southern New England" (Veit and Petersen 1993). Most razorbills of North America winter south of their breeding colonies; in large numbers as far south as Nantucket Shoals and Georges Bank (Hipfner and Chapdelaine 2002).

Habitat Requirements:
Cover.  Razorbills nest on "...small rugged offshore islands; eggs are typically laid on bare rock, usually tucked into a crevice, or under a large boulder" (Folger 1986). Historically, only 6 islands were known breeding sites in the Gulf of Maine (Folger 1986). Razorbill show strong nest site fidelity (Hipfner and Chapdelaine 2002).

Foraging.  Folger (1986) regards the cold waters of the Nova Scotia Current as the factor enabling razorbills and other 'northern' birds to have established breeding colonies in the Gulf of Maine.  Razorbills feed on small fishes and crustaceans. "In winter, razorbills feed primarily in waters of less than 30 fathoms..." (Veit and Petersen 1993). In the eastern Atlantic typically inhabits waters 20 to 40 m deep, over sandy bottoms. Major North American prey are capelin, sand lance and herring (Hipfner and Chapdelaine 2002). The adults are strong fliers, but breeding razorbills tend to feed in near shore waters (Thompson et al. 1999 in Hipfner and Chapdelaine 2002).

Foraging range varied from about 5 to 38 km from breeding colonies in Scotland, within 20 km in Ireland, 28 km in England, and 25 km in Wales; however, most foraging at the latter site was within 5 km(Benn et al. 1986 and Leaper et al. 1987, Lloyd 1982, Webb et al. 1985, Stone et al. 1982; all in Hipfner and Chapdelaine 2002). The median distance for incubating birds in Iceland was 51 km (Hilton et al. 2000 in Hipfner and Chapdelaine 2002.

Threats.  Razorbills were extirpated from the Gulf of Maine in the 1800's.  This was a result of egg collecting, hunting, human occupation of the islands, oil spills, and predation.  Protection of colony sites allowed their re-establishment on 3 islands by the mid-1900's (Folger 1986), and 7 islands in 1996-1999 (Maine Department of Inland Fisheries and Wildlife databases).

Habitat Mapping:
Data Sources: Occurrence information was obtained from the Maine Department of Inland Fisheries and Wildlife (MDIFW) Seabird Island Database, Pierson et al. (1996), and Veit and Petersen (1993).  The MDIFW observations represent active breeding sites; the other locations were regarded as known winter feeding habitats.

Winter feeding areas were mapped as marine waters, from subtidal to 180' depths, within ecological units (Keys et al. 1995) containing known razorbill occurrences, from any of the above sources. This general habitat was scored 0.1, but was scored 0.4 if within 5 km of known winter feeding sites.  Foraging areas within 50 km of nesting colonies was scored 0.5, and the colony islands scored 1.0.

Sources:

Folger, D.C. 1986. Historic and Present Status of Three Seabirds Species Nesting in the Gulf of Maine; Great Cormorant, Razorbill, Arctic Tern. Unpublished report to Maine Department of Inland Fisheries and Wildlife, Bangor ME.

Hipfner, J.M and G. Chapdelaine. 2002. Razorbill, Alca torda. In The Birds of North America, No. 635 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, and The American Ornithologists' Union, Washington, D.C.

Keys, J.E., Jr., J.C. Carpenter, S. Hooks, F. Koenig, W.H. McNab, W. Russell and W. Smith. 1995. Ecological units of the eastern United States - first approximation (map and booklet of map unit tables), USDA Forest Service. Atlanta, GA.

Pierson, E.C., J E. Pierson, and P.D. Vickery. 1996. A Birders Guide to Maine. Down East Books, Camden, ME.

Veit, R.R. and W.R. Petersen. 1993. Birds of Massachusetts. Massachusetts Audubon Society. 514 p.