Some birds sing with a Yukon accent. Well, it might be more accurate to say a northern dialect.

A White-crowned Sparrow sings its heart out, in a northern dialect. (photo: Cameron Eckert)

"It doesn't take very long for a birdwatcher who travels to realize that the song of a White-crowned Sparrow in the Yukon is radically different from the same sparrow in southern Ontario," says Cameron Eckert, a Yukon Bird Club director.

In a lot of bird species, the song changes from east to west across North America, he says, and in some species dialects also change from south to north. A Brewer's Sparrow in the Okanagan sings in a different dialect than a Brewer's Sparrow in the Yukon.

"You don't have to go very far to hear a difference in dialect."

Dialects emerge because birds' songs are partly inherited and partly learned. In many species, the young learn their songs from their parents in the nest, usually from the male, Eckert says.

While the nestlings are being fed, they hear their father singing and learn to sing what he sings, which might well be slightly different from the songs of males in other locations.

A few species of birds don't grow up with their parents. Brown-headed Cowbirds, for example, lay their eggs in the nests of other birds and leave the foster parents with the work of feeding the cowbird offspring.

Young cowbirds don't have the chance to learn their songs in the nest. Instead, male cowbirds learn to sing during their first winter roosting -- their first opportunity to hang out with other males of their species.

Especially among songbirds, the males do most of the singing. They use their songs to attract females of their species and to defend their territories.

"The females of many species can sing and do sing," Eckert says. However, they tend to sing a "whisper song" -- a softer, less complex version of the male's song -- and they sing it near the nest.

Most forest songbirds sing while perching on a branch, but birds in open country tend to sing while flying. So do birds that live near the open spaces of wetlands.

Getting up high lets the song carry further, Eckert explains. Lapland Longspurs and Horned Larks are among the more common Yukon songbirds that typically sing while flying.

Songbirds aren't the only birds with impressive songs.

"Some shorebird species have spectacular songs," Eckert says.

He describes the song of the Stilt Sandpiper as resembling the braying of a donkey.

"The Pectoral Sandpiper's song sounds like the low hum of an alien spaceship. You can't believe that sound is coming from a bird."

Shorebirds like sandpipers generally fly and sing at the same time, and some of them make quite a production of it. The American Golden Plover performs a "butterfly flight" while it sings, flapping its wings slowly like a butterfly rather than in the much faster pattern it uses at other times.

And then there are the mimics. In the flight song of the Bluethroat, a songbird that nests on the Yukon's North Slope, you might hear snatches of the songs of several other species, Eckert says.

Some particularly adept bird mimics don't restrict themselves to imitating other birds. Catbirds and mockingbirds, which live far to the south, are notorious for imitating cats and dogs, and there are reports of starlings imitating the ring of cell phones.

Birds also have a whole range of vocalizations termed calls rather than songs. Eckert explains that songs are longer and more ornate than calls. Songs are generally used for attracting mates and defending territory, while calls are may have a variety of more common uses.

The calls of chickadees are a common sound in a Yukon winter. The call that sounds like their name, chick-a-dee-dee-dee, is a way of announcing "I'm here" to the rest of the flock.

Chickadees also have an alarm call that every other bird in the boreal forest recognizes, Eckert says. When a chickadee shrieks its alarm, all the boreal birds react.

"You'll see grosbeaks and every other bird diving for the bush," he says. "Then, seconds later, a hawk will pass over."

For more information about the songs and calls of Yukon birds, contact the Canadian Wildlife Service at (867) 393-6700 or the Yukon Bird Club at yukonbirdclub@yknet.ca.