An Incursion of Large Owls

(This 720th Buffalo Sunday News column was first published on January 16, 2005.)

The large owls most often seen on the Niagara Frontier in winter are great horned owl, short-eared owl and long-eared owl. This year, however, may prove quite different.

Occasionally conditions in the boreal forests and tundra of northern Canada cause other owls to move south and we have rare opportunities to see them. These uncommon large owl species are snowy owl, hawk owl and great gray owl.

The specific conditions that initiate these incursions are not well known. They may in fact be different in different years. In one recent year, for example, apparently a lack of food caused the movement because many starving owls were brought to rehabilitators. Because the diet of these birds is largely voles - those little mammals that most of us call field mice - the cyclically changing populations of the tiny rodents probably have much to do with these owl incursions.

Something like the following scenario may occur: In one winter the mouse population peaks and well-fed owls respond by bringing off large broods of young that year. By the following winter the resulting overpopulation of owls has caused the mouse population to crash and available hunting grounds to be depleted. Excess birds have to seek new territories and the fortunate ones move south.

Early evidence this year, however, suggests that the cause may be something else because many birds that have already appeared have been in good condition.

Whatever the cause, hundreds of rare owls are moving into southern Canada and the northern United States this winter. In Minnesota, for example, by the end of 2004, over 200 hawk owls had been reported as were more than 1300 of the still rarer great gray owls. The situation in Canada north of Lake Ontario is similar.

What is best for those who enjoy observing unusual birds is the fact that these owls are unaccustomed to humans and are little bothered by us. They usually simply sit and peer at you as you approach. Because of this and their large size they are often photographed. You can see many of them like the superb ones by Canadians Judy Eberspaecher and Dave Mills appearing here on the website of the Ontario Field Ornithologists.

The most common of these three owls and the easiest to identify is the snowy owl, our only largely white owl. It is often seen sitting on the ground around airports or on perches along the Niagara River and the shores of Lakes Erie and Ontario. Sometimes, however, they visit the city or suburbs where they pose majestically on building roofs.

Like the snowy owl, the hawk owl is active in daytime. As the name suggests, it is hawk-like and thus unlikely to be confused with other owls. It is usually seen scanning for prey from atop a tree or telephone pole. Its relatively long tail, whitish facial disk outlined with black and falcon shape further identify it. The smallest of these three species, its fluffed out feathers still make it appear much larger than a crow.

By far the biggest-appearing of all North American owls is the great gray owl. In bulk it is almost eagle-sized; however, this appearance, like that of all owls, is deceptive. The great gray owl only weighs two to three pounds, its thick and deep feathering giving it both insulation and its larger profile. In fact, less bulky snowy owls and great horned owls weigh more.

For identification this large woodland owl shows a distinctive white mustache spreading widely from just below its bill.

As these and other boreal species move south from northern Ontario, they meet the Great Lakes and tend to accumulate north of them. For that reason we don't usually see them in this region. This year, however, with so many on the move the chances are greater that some will make it to the Niagara Frontier.

If you see one of these rare owls, please contact Dial-a-Bird at 896-1271 or dfsuggs@localnet.com or e-mail me so that this information can be recorded and communicated to other regional birders.-- Gerry Rising