Hawks, snowy owls flock to Wisconsin

In all four seasons, snowy owls and rough-legged hawks are never far apart. These beautiful and majestic hunters of the Arctic dance together in the wide open spaces of the arctic tundra for much of the year, sweeping south into our area and much of the northern United States for the winter season.

Two spectacular birds of prey, a pristine white owl and, in some cases, a charcoal black hawk, live out their lives in tandem, moving with the winds and the seasons of the sun. Choosing locations that most resemble their tundra homeland, the birds are never far apart, it seems. Where you find one, you will often come across the other.

Even as these Arctic hunters move south into our area to settle in for the winter season, drama sometimes plays out with explosive action among the grasslands and farmlands they frequent. There are skirmishes, there are interactions.

Sometimes, this means a quick flyby from an agitated hawk when a snowy is spotted on a quiet perch. Sometimes, it is the owl who is the aggressor. Sometimes, the assaults last for just a split second, while other times, a rough leg may harass a snowy for a full day or longer.

Regardless, these birds are not strangers.

"They may occasionally fight for a few seconds, but these birds come from the same place. They know each other," said Patricia Fisher, owner of The Feather Wildlife Rehabilitation and Education Center, New London, who specializes in birds of prey.

Fisher currently cares for a rough-legged hawk, recently brought to her facility unable to fly. That bird is under careful watch, unable to kill on its own and having trouble on the wing.

Our resident hawk, the massive red-tailed hawk, is generally not affected by the presence of either of these predators from the north, as the redtail inhabits different habitat, preferring open woodlands or the forest edge.

Rough-leg roundup

This winter, rough-legged hawks have appeared in incredible numbers across the open countryside in Wisconsin. On one trip alone between Brillion and Manitowoc this month, I tallied more than 40 rough-legs along the way. Similar numbers are being reported from around the northern states, particularly in the Great Lakes region, including Michigan, Pennsylvania, Ohio and Minnesota.

"We have them every year and they congregate where there are high vole populations with limited snow cover," said Tom Erdman, curator at the Richter Museum of Natural History at the University of Wisconsin-Green Bay.

"Deep snows will move the birds elsewhere," he said. "I recall a year down at the Bong Recreation Area where there were well over 120 buteos in the area and at least 50 were rough legs. Typically, an area with lots of buteos also will have snowies and perhaps both short and long-eared owls. Voles are gold."

Erdman said that rough-legged hawks will do some wandering during winter as conditions change throughout the season.

"The first birds show by the end of August, but it is usually toward the end of September," he said. "Often, they will move about in winter as conditions change, such as snow depth. I've seen movements in December, even January. They start moving north again in late March and April. Some second-year birds don't breed, so there is no urgency to head north."

Because of their large size, Erdman said, people often assume that rough-legs must feed on larger prey. However, like the snowies, these large hawks are mainly after lemmings in the north and meadow voles here on their winter hunting grounds.

"They are larger than our local redtails in wing and tail length, but they weight much less," Erdman said. "They are very buoyant in flight and often will simply turn into the wind and hover while searching the terrain below for small mammals. Compared to redtails, they have very small and quick feet. They are the ultimate 'mousers.'"

Black and white

Snowy owls have put on quite a show over the past few winters, a sign, perhaps, of successful consecutive breeding seasons in the Arctic. Often, winter populations of both of these birds are cyclical, as rough-legs and snowies are known to occasionally take a summer off from breeding if rodent populations on the tundra drop.

While snowy owls are easy to identify, rough-legged hawks can be a bit of a challenge. This is because nearly every bird wears a slightly different dress.

In addition, rough-legged hawks come in two color phases, as well as plenty of intermediate plumages.

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The light color phase, or light morph, is generally streaked overall dark brown and white, often with a large breast band in dark chocolate brown. Meanwhile, the dark color phase of the rough-legged hawk is a deep, rich, brown to black overall, making it a truly spectacular bird of prey.

"The interesting point about the dark morphs is that we know they are coming from the eastern Arctic," Erdman said. "Rough-legged hawks are circumpolar in distribution. All are light phase birds except in northeast Canada, where we have the dark morphs. The thought is there was a refugium there in past ice ages where the population was isolated long enough to develop dark morphs."

Erdman said adult dark morph females tend to be colored a rich chocolate brown, while the adult males are a beautiful charcoal black with banded tail.

— Rob Zimmer, Post-Crescent staff writer, writes about nature every Tuesday in his Nature Calling column. He is reachable at 920-993-1000 ext. 7154 or yardmd@postcrescent.com; on Twitter @YardMD