Photo: Glenn Bartley/Vireo

Ross's Goose

Anser rossii

This pint-sized relative of the Snow Goose has been surrounded by mystery and surprise. Explorers recognized it as a different bird as early as 1770, but it was not described to science until 1861; its Arctic nesting grounds were not discovered until 1938. Once thought to be very rare, or even on brink of extinction, its population has greatly increased in recent decades. Not until the late 1970s was it discovered that Ross's, like Snow Goose, can occur in a “blue” morph. Blue Ross's Geese are still rarely detected.
Conservation status Population apparently still increasing, as with some other Arctic-nesting geese (Snow and White-fronted). Ross's Goose often hybridizes with Snow Goose, but evidently not enough to be genetically "swamped" by the Snows.
Family Ducks and Geese
Habitat Tundra (summer), marshes, grain fields, ponds. In summer on Arctic tundra, especially flat tundra with mix of grassy areas and low matted thickets of dwarf birch or willow. In migration and winter, shallow lakes, freshwater marshes, flooded stubble fields, other agricultural lands.
This pint-sized relative of the Snow Goose has been surrounded by mystery and surprise. Explorers recognized it as a different bird as early as 1770, but it was not described to science until 1861; its Arctic nesting grounds were not discovered until 1938. Once thought to be very rare, or even on brink of extinction, its population has greatly increased in recent decades. Not until the late 1970s was it discovered that Ross's, like Snow Goose, can occur in a “blue” morph. Blue Ross's Geese are still rarely detected.
Photo Gallery
Feeding Behavior

Forages mainly by walking on land, or wading or swimming in shallow water. During migration and winter, feeds in flocks, usually with Snow Geese.


Eggs

4, sometimes 2-6, rarely 1-8. Dull white, becoming nest-stained. Female does all incubating, usually 21-23 days. Young: Leave the nest shortly after hatching, following parents to water. Both parents tend the young; male is most active in defense against predators. Young fledge in 40-45 days.


Young

Leave the nest shortly after hatching, following parents to water. Both parents tend the young; male is most active in defense against predators. Young fledge in 40-45 days.

Diet

almost entirely plant material. Diet for most of year is mainly green grasses and sedges. On arrival on breeding grounds, before new growth is available, do much grubbing for roots. In fall migration, feeds more on seeds and grains of wild grasses or cultivated crops.


Nesting

First breeding at age of 2 or 3 years. Courtship involves rapid head-dipping by both members of pair. Breeds in colonies, usually associated with colonies of Snow Goose. Nest site is often on island or shore of tundra lake, usually on edge of low thicket. The same site is often used for more than 1 season. Nest is a bulky bowl of twigs, leaves, grass, moss, lined with down. Female builds nest, beginning about the time the first egg is laid, continuing after incubation begins.

Illustration © David Allen Sibley.
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Text © Kenn Kaufman, adapted from
Lives of North American Birds

Migration

Main population migrates from Northwest Territories to central California, traveling along a rather narrow route with traditional stopovers, especially in Alberta and Montana. In recent years, numbers wintering in New Mexico and east of Rockies have increased markedly. Migrate in flocks, often mixed with Snow Geese, sometimes with other geese. Strays appearing far out of range may have arrived by traveling with other species.

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Migration

Main population migrates from Northwest Territories to central California, traveling along a rather narrow route with traditional stopovers, especially in Alberta and Montana. In recent years, numbers wintering in New Mexico and east of Rockies have increased markedly. Migrate in flocks, often mixed with Snow Geese, sometimes with other geese. Strays appearing far out of range may have arrived by traveling with other species.

  • All Seasons - Common
  • All Seasons - Uncommon
  • Breeding - Common
  • Breeding - Uncommon
  • Winter - Common
  • Winter - Uncommon
  • Migration - Common
  • Migration - Uncommon
Songs and Calls
Soft cackling and grunting notes.
Audio © Lang Elliott, Bob McGuire, Kevin Colver, Martyn Stewart and others.
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