Montana Field Guide

One of the most abundant species of waterfowl in the world. A medium-sized goose, with a distinctive blackish "grinning patch" or "smile." Total mean length: male 756.2 mm, female 728.9 mm; body mass of male 2,485 g, of female 2,181 g. Plumage dimorphic with light (primarily white) and dark (gray-brown) morphs. Sexes alike though male slightly larger; no seasonal variation. Adult white morph, completely white except for gray primary-coverts, and black primaries; occasionally rusty-orange staining on head and upper neck. Feet and legs dark pink; bill rose-pink with pale-pink or white nail. Adult blue morph, similar soft parts, but body largely dark gray-brown except for white head and foreneck. Upper wing-coverts gray, contrasting with blackish remiges and dark-brown mantle that is veiled with black and tinged blue; hind neck dark gray; rump pale gray; upper tail-coverts gray or white, contrasting with dark-gray tail that is broadly edged and tipped whitish; underparts varying in amount of dark brown and gray (Mowbray et al. 2000).

For a comprehensive review of the conservation status, habitat use, and ecology of this and other Montana bird species, please see Marks et al. 2016, Birds of Montana.

There is a Snow Goose migration pathway in Montana. The Blue Goose migratres to the east of Montana. In spring 1950, 150,000 were seen at Freezeout Lake.

Breeds colonially in subarctic and arctic tundra near the coast on relatively featureless terrain, near ponds, shallow lakes, streams, or islands in braided deltas. Winter range includes coastal areas, estuarine marshes, marine inlets and bays, shallow tidal waters and coastal freshwater and brackish marshes; inland, on wet grasslands, freshwater marshes, coastal prairies and cultivated fields. Migration routes bring them into northern Montana (Freezeout Lake) as a staging area. From staging areas they may follow several routes of migration. During migration Snow Geese use grain fields, lakes, and rivers (Mowbray et al. 2000).

Seeds, stems, leaves, rhizomes, stolons, tubers and roots of grasses, sedges, rushes, and other aquatic plants; grains and young leafy stems of various agricultural crops; stems of horsetails; and a variety of berries during winter and migration. During breeding season: leafy parts of grasses, sedges, rushes, willows, and other aquatic plants; rhizomes, tubers, and roots of grasses, rushes, sedges, forbs, and tundra shrubs. Brooding goslings may also feed on fruits and flowers, shoots of horsetails, and Chironomid larvae (Mowbray et al. 2000).

Breed in large, often dense, colonies north of the tree line from extreme northeastern Russia along the coast and islands of arctic and subarctic North America to Northwestern Greenland. Lifelong socially monogamous pair bonds. Nests on dry ground, often close to rocks or small shrubs that provide some shelter. Eggs or long oval to subelliptical in shape; creamy white in color but readily staining to dirty gray. Natural clutch size varies from 2 to 6. Breeding season late May through July (Mowbray et al. 2000).