Migration time: It’s one of the most rewarding parts of watching birds. The way migratory birds show up right on time in spring and fall, with each species following its own schedule, is both enjoyable and reassuring. But even though the routes and timetables may seem predictable, some birds do change their flight patterns over the years or decades. Here are a few examples of bird migration patterns that have changed.
Change Is In The Air: Bird Migration Patterns
Rufous hummingbird The change: Angling eastward
Nesting in the Northwest, from Wyoming to southern Alaska, rufous hummingbirds have traditionally spent the winter in Mexico. A few had always wandered east in fall, but until recent decades, they would not have survived the winter there. Now, however, gardeners all over the Gulf Coast and beyond have established winter havens for hummingbirds, with flowers that bloom through the season and plenty of sugar-water feeders. From east Texas to Florida and north at least to the Carolinas, hundreds of rufous hummingbirds now spend the entire winter, and some individuals may come back to the same gardens year after year.
The bird: Canada goose The change: Putting down roots
Once, Canada geese were symbols of the wilderness. In most parts of the U.S., they were absent in summer. Their flocks would arrive from the north along with the cold winds of autumn, and they would leave to go back to Canada early in the spring. As recently as the 1950s, some people feared that Canada geese might disappear completely. Various state wildlife agencies began trying to establish new flocks by raising young geese in captivity and releasing them locally. But because geese learn migratory routes from their parents, these newly introduced flocks lacked the know-how to migrate, so they became permanent residents. Today they are found year-round in wild marshes, city parks and golf courses over much of the U.S. Meanwhile, flocks of wild geese still migrate from the Arctic to the central states and back again, overlapping in some seasons with their nonmigratory cousins.
The bird: Barn swallow The change: Pioneering a new continent
There are dozens of kinds of long-distance migrant birds from North America that fly to South America for the winter. But these migratory birds never stay to nest on the southern continent. Well, almost never. During the last few decades, barn swallows have broken all the rules. They had always been known as wintering birds all over South America. In 1980, observers were startled to find six pairs actually nesting and raising young near Buenos Aires, Argentina. It seemed like a fluke, but it was really the start of something big. Their numbers have increased ever since, and there are now thousands of pairs of barn swallows nesting in Argentina—a range extension of about 4,000 miles from anywhere they had nested before! More bird stories tomorrow....till later this is Becky Litterer from Becky's Greenhouse, Dougherty Iowa Taken from Birds and Blooms.com