By John Coluccy, Ph.D., DU Biologist
Skeins of Canada geese winging their way south in fall and north in spring have long symbolized the changing of seasons and a connection to far-off, wild places. However, in recent years, an increasing number of people throughout the U.S. are seeing Canada geese in their communities year round. The last time I checked, there were still four seasons. Is this some new breed of Canada goose that has lost migratory behavior? Who are these year-round residents, and where did they come from?
Canada geese that nest and reside most or all of the year in the Lower 48 are collectively referred to as "resident" Canada geese. For the most part, these populations are sedentary and only migrate southward if winter weather is severe enough to limit food and open water. However, some members of resident populations participate in molt migrations.
Historically, resident Canada goose populations were found in each of the four flyways. By the early 20th century, however, following European settlement, the birds were extirpated from much of their range as a result of unregulated hunting, egg collecting, and habitat destruction. In fact, the giant Canada goose, the largest subspecies of Canada goose, was thought to be extinct for nearly three decades, until Harold C. Hanson of the Illinois Natural History Survey rediscovered it in remnant populations during the early 1960s. Present-day resident Canada goose populations originated from privately maintained captive flocks originally used as live decoys and food.
These populations consist of several large subspecies, or races, of Canada geese. The Atlantic Flyway population is believed to be of mixed racial origin, including Atlantic, interior, western, and giant Canada geese. The Central Flyway population predominantly consists of western, giant, and interior Canada geese. In the Mississippi Flyway, most resident Canada geese are giant Canada geese, while those in the Pacific Flyway are western Canada geese.
Today, resident Canada geese can be found throughout their former range and beyond and are considered one of North America's greatest wildlife management success stories. In fact, these grand waterfowl can now be found nesting in every U.S. state. Most biologists believe there are currently more Canada geese in North America than at any other time in history, largely a result of increasing resident populations. Current estimates suggest there are approximately 3.6 million resident Canada geese in North America: 1.1 million in the Atlantic Flyway; 1.3 million in the Mississippi Flyway; 1.1 million in the Central Flyway; and 0.1 million in the Pacific Flyway. While most North American Canada goose populations are stable or slightly increasing, resident populations have increased dramatically, and they now outnumber or rival migrant populations in each of the flyways.
What is it about resident Canada goose populations that have enabled them to increase so rapidly? Why have they been so successful? As a group, Canada geese are long-lived, with relatively high survival rates and low reproductive rates. However, the larger-bodied subspecies (which make up residents) have the highest reproductive rates and highest survival rates. In comparison to migrant Canada geese, residents begin nesting at a younger age, have larger clutches, and enjoy relatively stable and high reproductive success (nest success and gosling survival).
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