Wild Things: Snow Goose (Anser caerulescens)

The Snow Goose is a relatively large goose, standing about 30 inches high and weighing 6 pounds or more. Wingspan is about 3 feet. The species has increased in recent decades, due to warming in the arctic tundra of far northern coastal regions of Canada and Alaska where the birds breed. Warm temperatures increase the success of nestlings. Of the two subspecies, the western or lesser Snow Goose is the one we encounter in New Mexico. An dark morph, called the “blue goose” may be present, having dark areas on the body and wings and a white head.

In winter the geese travel down to the United States where they congregate around marshes, lakes, ponds, and grain fields. They are common in winter in New Mexico at the Bosque del Apache National Wildlife Refuge, where the photos here were taken. They may also be encountered wintering in the panhandle of Texas and up into eastern Colorado and western Kansas, as well as southern Arizona and California and other areas in northern California, Oregon, Washington, Nevada, and Utah. A large migrant population winters along the Mississippi watershed.

Pairs form long-lasting bonds and females tend to return to breed to the same area where they were born. She usually lays 3 to 5 eggs on a ground nest and lines it with down for cushioning. The hatchlings are active after birth and are able to feed themselves, but remain with the parents for protection and travel with them for the first two or three years. The birds will first mate and breed as three-year-olds.

Young are vulnerable to predation from Arctic foxes and Skuas on the breeding grounds. Coyotes and wolves are also known to take young geese from nests. The proximity of geese nests to Snowy Owl nests has actually been shown to reduce mortality in Snow Geese nestlings, it is believed due to the tendency of the owls to inhibit other predators from approaching the Snow Goose nests. Bald Eagles will take Snow Geese on their wintering grounds. I got a video of a Bald Eagle feeding on a Snow Goose carcass at the Bosque Wildlife Refuge.

The Snow Goose population is now estimated to include some 3 million birds, a dramatic increase since the mid 1970s. Climate warming and has resulted in range expansion in the Hudson Bay region. And conversion of previous forest areas to agricultural and grassland uses has also created new habitats for the geese. Snow Geese feed on the all parts of plants, the roots, leaves, and seeds. They will also take fruiting berries in fall. The crop fields maintained at the Bosque Wildlife Reserve provide waste grains in winter that are favored by the geese. Lacking teeth, Snow Geese have serrated edges on their bills that allow them to cut and tear tough plant matter while foraging.

The population of Snow Geese is now so large that they are causing environmental damage in their breeding grounds and having negative impacts on other arctic breeding species. Control measures like larger hunter bag limits and longer hunting seasons have been implemented to reduce the population. The Audubon Society predicts that Snow Goose breeding range will continue to expand in northern Canada as global warming proceeds.

James Taulman is a semi-retired research wildlife biologist who worked with the U.S.F.S. research branch and taught zoology, ecology, and more in several university positions. He lives in the East Mountains, and explores natural areas observing native wildlife and conducting independent research projects. Search for James Taulman on Youtube to see wildlife videos.