The Snow Goose (Anser caerulescens) is an abundant migratory waterbird that visits the United States every winter.
Many American birdwatchers will be familiar with the sight of these white and black birds flying high overhead on their annual migration, even if they do not usually see them at ground level. But where do these birds go each year? Why do they migrate at all?
Snow Geese migrate to the Arctic and subarctic zone of North America, as well as marginal areas of neighboring Russia and Greenland to breed each year. They time their arrival to coincide with the melting snow and thawing ice. Once breeding is complete, the birds molt and then begin a long migration that takes them as far south as Central Mexico.
The tundra of the far north provides rich foraging grounds and a relatively safe place for these birds to raise their family of 2 to 6 goslings. At such high latitudes, the summer is short-lived, however, and the birds must head south because they cannot survive the coming harsh winter.
They escape the extreme northern winter by making their way south along major flyways to spend the winter in the relatively mild climate of the Lower 48 states.
Read along to learn more about where, why, and when Snow Geese migrate.
A flock of migrating Snow Geese flying north during spring migration
Snow Geese are medium-distance migrants that migrate every year. These colonial nesters undertake a lengthy migration from their northern breeding grounds in Alaska and Canada to their overwintering grounds in the USA and Mexico each fall before returning the following Spring.
The timing of Snow Goose migration is highly dependent on weather conditions. Their northward migration is triggered by rising temperatures and they do not lay their eggs until the ice has thawed in their breeding grounds. The birds must molt after breeding and are unable to fly until their new feathers have grown out.
The exact dates of arrival and departure do vary year to year for these reasons, but Snow Geese usually begin their spring migration by mid to late winter and arrive at their breeding grounds by the end of spring. Their return trip to their overwintering grounds begins in early fall and ends in early winter.
There are several breeding grounds in the north of the Snow Goose distribution and several overwintering grounds in the United States and Mexico. Due to the different climatic conditions at each site, the timing of arrival and departure naturally varies between the different populations as well.
Migratory Snow Geese are grouped into western, mid-continent, and eastern populations. Read on to learn when you might spot Snow Geese in your area:
White-morph snow goose foraging on the north shore of the St. Lawrence River during the spring migration, Quebec City, Quebec, Canada
Snow Geese migrate to take advantage of the favorable foraging and breeding conditions of the northern summer. There is little competition for resources from resident wildlife and a reduced threat of predation of their chicks and goslings due to the harsh winter conditions of the region.
Naturally, these migratory geese must depart for milder climates when cold conditions return and food resources dwindle. At this time, Snow Geese migrate south to lower latitudes where winter conditions do not leave the landscape in darkness and blanketed in snow and ice.
The different populations of Snow Geese migrate varying distances depending on the locations of their breeding and overwintering grounds. The birds that overwinter in central California, for example, migrate over 3,000 miles one way to breed in the northeast of Russia, only to return south a few months later.
A flock of Snow Goose in Japan
Snow Geese migrate between their summer breeding grounds in the Arctic and sub-arctic tundra and their overwintering grounds in the United States and Mexico. Read on to learn more about these areas:
Snow Geese spend the breeding season in various breeding colonies located from Siberia in the West, across Alaska, and Canada, and as far as Greenland in the east. Their breeding sites are generally located on relatively flat, grassy terrain near water bodies such as streams, ponds, and lakes.
Once breeding and molting are complete, Snow Geese begin a southward migration that takes them thousands of miles to their overwintering grounds in several separate regions of southwestern Canada, Western, midcontinental, and Eastern USA, and in Mexico further to the south.
Such a wide geographical range means their overwintering habitat differs pretty significantly, but their habitats tend to be open and moist. Depending on the area, Snow Geese tend to spend the winter in the following habitats:
Close up of a Snow Goose resting in the snow in the sunshine
The Snow Goose migration is a pretty drawn-out affair that lasts 3 or 4 months. They begin their northward spring migration as early as February in the south of the United States and arrive at their breeding grounds by the end of May. Their return migration in the fall begins in September and is usually completed by December.
Snow Geese do not complete their migration without stopping. In fact, these birds make long stopovers at regularly used staging grounds.
Five Snow Geese in flight together
Snow Geese are known for migrating in huge flocks, although the actual numbers do vary greatly between groups and time of year. Snow Geese tend to migrate in larger flocks during their southward fall migration. At this time, flocks of over 1000 birds are the norm, and the sight and sound of these birds is something to behold, even though they fly at high altitudes.
During their spring migration to the north, Snow Geese tend to travel in smaller flocks ranging from a few dozen to a few hundred individuals. Snow Geese are also known to migrate in mixed flocks with Canada Geese from time to time.
A large flock of migrating Snow Geese taking off
Snow Geese may form lifelong pairs on their second northward spring migration. It is unclear as to whether the pair will fly close together during each subsequent migration, although they will mate for life and return to the same nest site year after year.
All Snow Geese are migratory. The only individuals which do not migrate are those that are injured, sick, or too old to undertake the journey. Their northern breeding grounds are simply too cold and inhospitable for the birds to survive through the winter.
A pair of Snow Geese landing to join the large flock
Snow Geese overwinter in varying numbers across most of the Lower 48 states. There are three main overwintering populations, however, where these birds are most common. Read on to learn which states they visit during the non-breeding season.
Snow Geese visit several breeding colonies in the Arctic and subarctic during the summer. The following areas are major breeding colony sites:
A large flock of migrating Snow Geese in Tennessee
Snow Geese migrate both during the day and the night, although they tend to take off around dusk.
Large numbers of Snow Geese fly as far south as the Gulf Coast of Texas and Louisiana, although some birds fly even further south to Central Mexico.
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