For millennia, generation after generation of birds have followed the same routes for hundreds, sometimes thousands, of miles from breeding grounds to wintering areas in the fall. And the journey is repeated again in spring. Scientists have never completely solved this mystery of nature. The belief, though, is that geographic landmarks, magnetic fields, and the position of the sun, moon, and stars all play a route in assisting bird navigation.
Waterfowl migration corridors are known as flyways and two cross through Ontario: the Mississippi Flyway and the Atlantic Flyway. Boundaries are not definitive hard lines, as individual species don’t follow the same route as others while travelling.
The Mississippi Flyway extends from northwest Alaska east past the shores of Hudson Bay in Quebec. It funnels birds through the boreal forest and prairies of northeastern Alberta, Saskatchewan, and Manitoba, and across the Great Lakes to wintering areas along the Mississippi River and Gulf of Mexico.
In Ontario, the Mississippi Flyway encompasses the western portion of Lake Erie, Lakes St. Clair, Huron, and Superior. Even Mississippi birds coming from Quebec generally don’t use Lake Ontario.
In the north, the Atlantic Flyway starts close to the Yukon/Northwest Territories’ border and extends across to Labrador. Along the way, it touches northeastern Alberta, central and northern Saskatchewan, all of Manitoba, northern Ontario, and extends along the Atlantic seaboard into Florida. The Atlantic Flyway encompasses all of Ontario.
Many species of waterfowl are found in both flyways, but some are individual to each. Canvasbacks, lesser scaup, blue-winged teal, and gadwall are typical of the Mississippi Flyway. The mallard has expanded its range in North America, but was traditionally a western breeder that migrated through Ontario on the Mississippi Flyway. Even today, many migratory mallards come through here.
Black ducks seen in Ontario are an Atlantic Flyway bird and exclusively an eastern North American species. Snow geese in eastern Ontario are reaching such numbers there will be a spring hunt next year. They, as wood ducks, are Atlantic Flyway birds.
Duck bands from birds hunters harvest reveal much about their migration patterns. Birds banded in both the Central and Pacific Flyways are harvested in Ontario, even though neither flyway crosses into the province.
Although many of the birds passing through Ontario are from the west, many lakes and wetlands here are also breeding grounds for ducks and geese. “It’s not as concentrated a production as you get in the prairies,” said Dr. Scott Petrie, executive director of Long Point Waterfowl (LPW). Band data shows most of the wood ducks and ring-necks harvested in Ontario were a product of the province. Even southern Ontario produces a lot of Canada geese, mallards, and wood ducks. About two-thirds of the geese harvested in Ontario are temperate breeders, birds produced in the southern half of the province.
Migration patterns can change as waterfowl take advantage of open water on the Great Lakes in warmer years and winters with less snow covering field crops. Joint surveys by LPW and the Canadian Wildlife Service reveal the number of sea ducks, such as long-tails and goldeneyes, overwintering in Ontario increases in years with mild winters.
“What is clear is that during milder winters many waterfowl species can adapt to the more favourable conditions and often will remain farther north in greater numbers during the winter,” said Mark Johnson, spokesperson for Environment Canada.
Wetlands are important for waterfowl for breeding, wintering, and migration. The sad part is, Ontario is still losing wetlands.
According to Ducks Unlimited Canada’s Southern Ontario Wetlands Conversion Analysis, there were 2 million hectares (4,940,000 acres) of wetland across southern Ontario. By 2002, only 560,844 hectares (1,385,845 acres) remained. And, there are still hundreds of hectares lost per year, adding another variable in the ancient migration paths of waterfowl.