Ross's Goose

The Ross's Goose is a charming, diminutive goose native to North America. Historically considered a rare species, its populations have rebounded spectacularly over the past half-century. Visually, it is nearly identical in plumage to the larger Snow Goose (Anser caerulescens), but its compact, mallard-sized body and distinct facial profile make it a favorite subject of study for birdwatchers looking to hone their identification skills in mixed wintering flocks. It is named in honor of Bernard R. Ross, an associate of the Smithsonian Institution and a factor for the Hudson's Bay Company in the Northwest Territories, where the goose was studied.

Identifying a Ross's Goose requires close attention to structural proportions and bill morphology, especially when they are mixed within large flocks of Snow Geese.

Key Field Marks

• Size: Noticeably smaller than a Snow Goose, closer to the size of a Mallard or a Cackling Goose. It has a shorter, stockier neck and a more rounded, compact head shape.
• Bill Profile: The bill is short, stubby, and triangular. Unlike the Snow Goose, the Ross's Goose lacks the dark, curved "grin patch" (or tomium) on the cutting edges of the bill, giving its mouth line a straight, neat appearance.
• Nasal Caruncles: Mature adults develop bluish-gray, warty bumps (caruncles) at the base of the pink bill, adjacent to the face. The extent of these warts increases with age.
• Plumage: The vast majority of Ross's Geese are white morphs, displaying pure white plumage with contrastingly deep black primary feathers on the outer wings.

Rare Morphs and Hybrids

• Blue Morph: An extremely rare dark-morph Ross's Goose exists, displaying a dark body and a white head, similar to the "Blue Goose" phase of the Snow Goose. However, blue-morph Ross's Geese make up less than 1% of the total population.
• Hybridization: Ross's Geese occasionally hybridize with Snow Geese. Hybrids are intermediate in size and exhibit intermediate bill structures, which can make identification highly challenging.

Throughout the year, the Ross's Goose utilizes distinct geographic regions spanning from the high Arctic to the southern United States and northern Mexico.

Breeding Range

During the summer nesting season, Ross's Geese inhabit the damp, low-lying tundra of the Canadian Arctic. The vast majority breed in the Queen Maud Gulf Migratory Bird Sanctuary, though smaller colonies exist on Southampton and Baffin Islands, and along the western coast of Hudson Bay.

Migration and Wintering

With the onset of autumn, they migrate south along the Central and Pacific Flyways. Historically, their primary wintering grounds were confined to the Central Valley of California. However, in recent decades, their wintering range has expanded significantly eastward. They are now commonly found wintering in agricultural wetlands across New Mexico, Texas, Arkansas, Louisiana, and parts of north-central Mexico. During migration and winter, they frequent shallow lakes, reservoirs, flooded agricultural fields, and pastures, often alongside millions of other waterfowl.

Ross's Geese are highly social, gregarious birds that rarely travel alone, almost always associating in large flocks with Snow Geese and Greater White-fronted Geese.

Feeding

These geese are strict herbivores. On their breeding grounds, they graze heavily on the tender shoots of sedges and grasses. On their wintering grounds, they travel in tight, sweeping flocks across harvested fields of corn, rice, barley, and wheat to feed on waste grain. Because of their small, delicate bills, they are highly efficient grazers close to the ground.

Vocalizations

Their voice is distinct from the deeper, nasal honk of the Snow Goose. The call of a Ross's Goose is a higher-pitched, squeaky, and metallic keek or kowk. When a massive flock takes flight, the combined sound of thousands of Ross's Geese can sound like high-pitched, excited chatter.

Nesting

Nesting occurs in colonies on tundra islands within shallow lakes, which provides protection from terrestrial predators like Arctic foxes. The female constructs a ground nest lined with mosses, grasses, and her own downy feathers. She incubates a clutch of 2 to 6 eggs for about 22 to 24 days while the male stands guard. The young are precocial, leaving the nest within 24 hours of hatching to feed alongside their parents.