A diminutive version of the familiar Snow Goose, Ross’s Goose is also white with black wingtips but has a shorter neck and stubbier bill. These gregarious waterfowl can form huge flocks on their own, and smaller numbers also join enormous flocks of Snow Geese. Both these species have seen population explosions as climate change has warmed their arctic breeding grounds, reducing snow cover and increasing plant growth. The two species seem to be hybridizing more frequently as warming allows their breeding ranges to come into contact.
Ross’s Geese are reliably seen in winter in California, New Mexico, Texas, and Louisiana. They move around during the day, seeking out the best fields or marshes for foraging, but they usually return to refuges or reservoirs in the evening to roost. Even far from regular wintering locations, a few Ross’s are often scattered among flocks of Snow Geese or other geese. Patient scanning of flocks with a spotting scope is the best method to find them; look for the Ross’s smaller size and shorter, more triangular, mostly pink bill.
A Ross’s Goose can often be picked out of a large flock of Snow Geese by its immaculate white head, lacking the yellow staining of Snow Geese that have been rooting deeply for tubers in marshes. Ross’s Geese tend to forage more on plants at the surface.
The female Ross's Goose does all of the incubation of the eggs. The male stays nearby and guards her the whole time. The female covers the eggs with down when she leaves the nest. The down keeps the eggs warm while she is away and may help hide them from predators.
Populations of arctic-nesting geese, especially Ross’s Geese and Snow Geese, have changed the plant communities in the places where they nest. Their large, growing colonies strip vast areas of vegetation, in some areas nearly down to bare ground. Some of these denuded areas of tundra are visible from space.
Downy young come in two colors: yellow and gray. The two forms look identical once they get real feathers.
Very rarely, a Ross's Goose can be found that is dark-colored like a blue morph Snow Goose.
Prior to the 1950s the Ross's Goose was confined to well-defined breeding and wintering areas, with few seen as strays. Since that time the species has been expanding eastward, both on the breeding and wintering grounds. The change in breeding distribution has resulted in more contact and subsequent hybridization with the Snow Goose.
The oldest known Ross's Goose was a female, and at least 22 years, 6 months old when she was taken by a hunter in California in 1993. She had been banded in 1972 in Saskatchewan.