Every winter, the population of Yukon communities is bolstered by a crowd of lively, raucous, and very visible visitors -- ravens.

A raven takes flight, escaping Cameron Eckert's camera. (photo: C. Eckert)

On a cold night, you hear a metallic knocking from high above and look up to see a raven snuggled on top of a street light, feathers fluffed out, taking advantage of the light's warmth. On warm days, raven pedestrians walk, not fly, through city traffic to check for anything edible in the debris left by passing cars.

Everyone has a raven story.

There was the dog that spent a hungry winter tormented by ravens. Every day, when its dinner was set out, the ravens were waiting. One perched at the far end of the yard, cawing, flapping its wings, and making an offensive nuisance of itself. While the infuriated dog rushed to that end of the yard, the bird's partner stole food from the dog's dish. Then the birds swapped roles so that both could eat their fill.

Environment Canada biologist Jim Hawkings says dog food is one of the attractions that draws ravens into town in winter.

"They are naturally scavengers," he explains. "They eat dead things in the winter. There is a limited supply of this in the wild during winter, so they come into town."

"In town, they eat garbage (at the dump, at the curb, on the road, in the back of your truck), fast food dropped in the parking lot, dog food (often stolen from dogs in the backyard!). The dump always has hordes of them because of the amount of food available there."

Hundreds of ravens congregate at the Whitehorse landfill in winter. The annual Christmas bird count regularly records between 700 and 1000 ravens at the landfill. In 1997, observers recorded a spectacular 1409 ravens at the dump on Boxing Day.

It takes more than food to survive a northern winter, but ravens are equipped to deal with the cold, says Hawkings.

"Like all birds, they have very little muscle in the unfeathered parts of their legs, mostly just skin, bone, and tendons, so they don't lose a lot of body heat from there. Ravens living in the far north have thicker skin on their feet than do ravens in the tropics."

They also help each other out. They roost communally, usually in thick conifers, so that shelter and shared body heat help keep them warm.

"I have often seen ravens flying from somewhere early in the morning twilight," says Hawkings. "I suspect they go to some sheltered place at higher elevation than the valley floor, a place where it is probably quite a bit warmer because of the temperature inversion during a cold spell."

Cameron Eckert, a Whitehorse bird photographer, says that, despite their apparent boldness, ravens are "devilishly hard to photograph."

"A raven will be sitting there as casual as can be, looking right at you; but as soon as you raise the camera, it hops away. Occasionally, I get a good portrait photo by slowly raising the camera and pretending not to point it at the raven."

Hawkings agrees that ravens are smart and suprisingly cautious.

"I'm always intrigued by the way ravens will boldly hop into the back of a pickup truck and go about their business while people walk past only a few feet away," he says. "But if you slow down or stop or show any visible interest, they get very nervous in a hurry, and more often than not will fly away immediately."

The ravens in the Yukon are Corvus corax or common ravens, part of the corvid family. Members of the family include other raven subspecies, crows, jays, magpies, and nutcrackers.

Ravens can live for decades. The captive birds at the Tower of London typically live from 20 to 25 years, and one even made it to the ripe old age of 41. In the wild, they typically mate for life, returning to the same nesting spot year after year to raise their young.

In the Yukon, ravens nest anywhere from the forests of the south to the coast of the Beaufort Sea. As early as the middle of March, the ravens begin moving out of town to build or repair their nests.

Some ravens, however, are town birds year-round. Several hundred have been reported around the Whitehorse landfill in mid-summer. The authors of Birds of the Yukon Territory speculate that summer dump ravens are probably non-breeders and note that many of them seem to be in poor condition, possibly surviving on the dump food past the time when they could have survived in the wild.

For more information about ravens, contact the Yukon Bird Club through its website at www.yukonweb.com/community/ybc.