Snow Geese

Snow Geese are one of the most commonly seen of all the water fowl in the United States. It is not uncommon to see flocks containing hundred's of thousands of birds. They are native to North America and are sometimes referred to as the Blue Goose. The two common names of Blue and White refers to the range of colors that this bird comes in. They will range from completely snow white with black markings on their wings to bluish color and even speckled varieties like the pictured here.

They breed in the northern most parts of their range, Greenland, Canada and Alaska. White- and blue-morph birds interbreed and the offspring may be of either morph. These two colors of geese were once thought to be separate species; since they interbreed and are found together throughout their ranges, they are now considered two color phases of the same species. The color phases are genetically controlled. The dark phase results from a single dominant gene and the white phase is homozygous recessive. When choosing a mate, young birds will most often select a mate that resembles their parents' coloring. If the birds were hatched into a mixed pair, they will mate with either color phase. They will migrate south during the winter and it is at this time that they come into Missouri in HUGE numbers. Squaw Creek NWR refuge sees up to a million of these birds each winter. 

 White- and blue-morph birds interbreed and the offspring may be of either morph. These two colors of geese were once thought to be separate species; since they interbreed and are found together throughout their ranges, they are now considered two color phases of the same species. The color phases are genetically controlled. The dark phase results from a single dominant gene and the white phase is homozygous recessive. When choosing a mate, young birds will most often select a mate that resembles their parents' coloring. If the birds were hatched into a mixed pair, they will mate with either color phase. Snow geese breed from late May to mid August, but they leave their nesting areas and spend more than half the year on their migration to-and-from warmer wintering areas.

During spring migration, large flocks of snow geese fly very high along narrow corridors, more than 3000 miles from traditional wintering areas to the tundra.

Outside of the nesting season, they usually feed in flocks. In winter, snow geese feed on left-over grain in fields. They migrate in large flocks, often visiting traditional stopover habitats in spectacular numbers. Snow geese often travel and feed alongside white-fronted geese; in contrast, the two tend to avoid traveling and feeding alongside Canada grey goose, who are often heavier birds.

The population of Greater Snow Geese was in decline at the beginning of the 20th century, but has now recovered to sustainable levels. Snow Geese in North America have increased to the point where the tundra  breeding areas in the Arctic and the salt marsh wintering grounds are both becoming severely degraded, and this affects other species using the same habitat.

Major nest predators include Arctic foxes and Skuas. The biggest threat occurs during the first couple of weeks after the eggs are laid and then after hatching. The eggs and young chicks are vulnerable to these predators, but adults are generally safe. They have been seen nesting near Snowy Owl nests, which is likely a solution to predation. Their nesting success was much lower when snowy owls were absent, which leads scientists to believe that the owls, since they are predatory, were capable of keeping predators away from the nests. Few predators take snow geese away from the nests, but Bald Eagles do take them given the chance.

 The dark color of the blue morph Snow Goose is controlled by a single gene, with dark being partially dominant over white. If a pure dark goose mates with a white goose, the offspring will all be dark (possibly with white bellies). If two white geese mate, they have only white offspring. If two dark geese mate, they will have mostly dark offspring, but might have a few white ones too.

Snow Goose hunting in the eastern United States was stopped in 1916 because of low population levels. Hunting was allowed again in 1975 after populations had increased. Populations have been growing so large that the geese are destroying nesting habitat. Hunting has not slowed the dramatic increases in population size.

Populations have been growing exponentially in most parts of the range. Some colonies are becoming so large that the geese are destroying nesting habitat, and hunting is proposed to decrease the populations.

Which is smarter, a snow goose or a crow? This seems like a ridiculous question. In folklore, the goose is regarded as “silly,” and the crow is regarded as wily.

When Aphrodite first came ashore she was welcomed by the Charities (Roman "Graces"), whose chariot was drawn by geese.

 References:

Cornell University

Aboutbird.com

Wikipedia