The last raptors of winter

It’s last light, late April, in Baudette, Minnesota. Here, straddling the U.S.-Canada border, it’s also no passports required for northbound raptors hovering in the fading sunlight like otherworldly apparitions.

In the lowlands of Minnesota’s Laurentian Mixed Forest Province, dozens of Rough-legged Hawks (Buteo lagopus) on their spring migration to arctic nesting grounds have arrived at a vole buffet. The abundant rodents fuel the hawks on the next leg of their journey, says wildlife biologist Scott Laudenslager, area supervisor at the Minnesota Department of Natural Resources.

The Rough-legged Hawk is a large, long-winged buteo of open habitats. The raptor, named for its feathered legs, breeds in arctic and sub-arctic regions of North America, Europe, and Asia. The International Union for Conservation of Nature rates the Rough-leg as a species of “Least Concern.” Nonetheless, the bird faces habitat loss, climate change, environmental contaminants, and disease.

In autumn, Rough-legs leave the arctic and move south to areas with “milder” weather in southern Canada and the northern U.S. Wintering Rough-legs usually choose open habitats similar to their tundra breeding grounds, such as agricultural lands and airports. Where food is plentiful, the raptors often concentrate in large numbers.

This spring, late snows have slowed the hawks’ return north. As much as two feet still blanket the woodlands and prairies around Baudette. “Rough-legs migrate through here in big numbers, although usually earlier in spring,” Laudenslager says. “Their migration depends on snow depth and whether they can find food while they’re on their way north.”

If the number of Rough-legs along Minnesota County State-Aid Highway (CASH) 1 is any indication, Baudette offers a smorgasbord. One glance across an ice-rimed field of osier dogwood shrubs, bright red in winter, produces five Rough-legs. Most hover above potential prey, characteristic of the birds. Some perch on roadside utility poles, fence posts, or twigs at the tops of bare-branched trees. Both Rough-leg morphs, light and dark, are in view, although light morphs, with their whitish plumage, seem more common here.

Bumping along CASH 1’s snow-ice-mud ruts in a four-wheel-drive SUV, we spot three or more Rough-legs every quarter mile. According to the invaluable book Birds in Minnesota by Robert Janssen, 75 Rough-legs were seen on March 18, 2006, in Wilkin County, on the western edge of the state; 63 were counted on April 1, 2011, along a rural road in Kittson County, in Minnesota’s northwestern corner.

This April’s Rough-legged Hawks on CASH 1 may have eclipsed those numbers. For birders and photographers who happen upon them, as we did, they’re a last raptor gift of winter.

Tips from Pete Dunne for identifying hawks in flight