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Wisconsin Natural Resources magazine

Wisconsin Natural Resources magazine

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December 2005

Invasion of the vole snatchers

A rare winter treat of northern owls had birders flocking to northern Wisconsin.

Susan Foote-Martin


The great gray owl is North America's largest native owl. It has keen vision and hearing.
© Richard Armstrong
In the know: a few birding terms, a few facts

We knew they were coming. In fall 2004 the birding Internet chat lines in Canada were abuzz with sightings of great gray, northern hawk and boreal owls moving south in small groups. But how many would come into the United States and where they would show up was anybody's guess.

Why were owls on the move? Population estimates of small mammals conducted earlier in 2004 in Canadian boreal forests yielded the lowest numbers of voles in recent history. As the favorite prey for these owls, few voles meant certain death by starvation unless the owls moved farther south to find food as colder weather approached, so the irruption was on.

Bird watchers are a generous lot who like to share the experience with others. They stay in touch year-round on the Internet and through telephone hotlines describing when and where birds are moving through a region. By fall, the northern owls of Canada began arriving in Wisconsin and Minnesota in unparalleled numbers. Reports from Minnesota logged the first sighting of a great gray owl on August 17th and by January their numbers had swelled to nearly 2,000 individuals. Hundreds of northern hawk owls and boreal owls were part of this same irruption and sightings of all three species would nearly triple by late winter. Soon the Wisconsin bird-watching community began sharing details of their owl sightings. Enthusiasm for this once-in-a lifetime event was building across the state.

Order free Birding and Nature Trail Guides to the Lake Superior Northwoods and Mississippi and Chippewa Rivers regions by calling the Wisconsin Department of Tourism at 1-800-432-TRIP.

Over the winter months and continuing well into spring, people traveled north to see the owls and report their sightings on the Wisconsin Society for Ornithology's (WSO) birding chat line.
Media accounts across the state and nation spun a story of a "great owl invasion." From the pages of the New York Times and National Geographic magazine to CNN and ABC, word of the northern owls traveled far and wide.

The wildlife-loving public was driving and flying to northwestern Wisconsin from across the U.S. and from as far away as England to partake of this great phenomenon. Fortunately, our Great Wisconsin Birding and Nature Trail for the Lake Superior Northwoods Region was there to guide them. This 72-page, full-color publication is the first of a series of five guides. The free publication contains descriptions and maps for 88 of the best wildlife viewing sites in the state's northernmost counties. Many of these sites were perfect places to see the owls. All of the sites listed in our viewing guides are nominated by the public as favorite places to find birds and wildlife in native habitat.

Some of the most popular places to see great gray owls in Wisconsin early in the season were at Wisconsin Point in Superior (site #30 in our guide) and on the south edge of Crex Meadows State Wildlife Area (site #20) in Grantsburg. In a normal year, we might have had a single sighting of a great gray or a northern hawk owl at Wisconsin Point. Curt and Arlys Caslavka of Middleton saw 21 great gray owls at Wisconsin Point the day they visited.

"A viewing guide is perfect for this group of travelers," said Signe Holtz, bureau director for DNR's Endangered Resources program. "For the first time, we have compiled the best wildlife viewing venues in northern Wisconsin into one mapped auto trail. It contains detailed directions, site descriptions and tells the public what species they can expect to see. Now that we've tested it during this owl irruption, we know that it works."

Another full-color, high quality guide for the 13-county Mississippi/Chippewa Rivers region was just published in November. Similar Birding and Nature Trail guides for the Lake Michigan, Central Sand Prairies, and Southern Savanna areas of Wisconsin will be published through 2008. Within just a few years, Wisconsin will have a full set of guides to put anyone within arm's reach of nature-watching hot spots in the state.

Moreover, the local communities where these birds take up residence can also get a boost from ecotourism. The guides contain websites and contact information for local chambers of commerce and visitors bureaus so travelers can find a place to stay and discover more about nearby amenities. And with more than $400 million spent on wildlife viewing in Wisconsin each year, there is good reason for merchants to take notice.

"People came north from all over the country to see these beautiful creatures," said Lisa Hobbie, manager of the Best Western Northwoods Motel in Siren. "Employees enjoy meeting the birding public and share some of their owl sighting locations. Our customers love our Northwoods, and the owls teach us to appreciate what we have in our own back yards."

The Wisconsin Department of Tourism has taken on a full partnership with the Department of Natural Resources in publishing and distributing the guides. "The project is a winner for both agencies, and we're glad to be a part of it," says Tourism Secretary Jim Holperin. "Our customers want to know where to go to view wildlife, and we can put the viewing guides in their hands and send them to the best places in the state to enjoy our natural resources along with Wisconsin hospitality."

The owls of winter gave many people an unusual chance to connect to nature on their own terms, face-to-face and eye-to-eye. These owls have relatively little contact with people and are consequently unfazed by human contact. Thousands of people saw great gray and northern hawk owls for the first time in their lives at very close range. Schoolchildren to grandmothers called us, e-mailed and sent handwritten notes describing their experiences. It was clear that they had found something special and they wanted to share it.

One such encounter was with a great gray owl that came for an extended stay in the Columbia and Dane county communities of Arlington and DeForest. The kids in the area called him "Wilson."

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The great gray owl and other boreal owls have little exposure to people and little fear of human ways. This allowed an unusual opportunity for a close look at "Wilson."

© Steve Marfilius

Wilson arrived in mid-February and stayed until his untimely death on March 26 when he was struck and killed by a car. During that time hundreds of people came to get a close look. For me, his photographs have more personality than those of other great grays I saw last winter because I came to know him personally. He was part of my daily ritual as I drove to and from work, and I would look for him on the weekends too.

Wilson helped bird-watchers make new friends. He gave us opportunities to learn and teach more about nature. He gave us a glimpse into the lives of birds that normally live in the vast and sparsely populated boreal forests of the world that most people might never visit. He touched the lives of many. He taught us what happens when our habitat fails to provide for our needs and death becomes a possibility.

Like so many others of his kind that came south last winter, Wilson had no fear of cars, as they are rare occurrences in the boreal forest. Hundreds of great grays died during the irruption because they learned to hunt for food along roadside corridors that stayed warmer and attracted prey. The birds did not recognize car and truck traffic as a threat. Thankfully, many injured owls were successfully rehabilitated and released back into the wild.

We all hope for another winter to remember; a time of owls and of special opportunities to venture out, learn new things about the natural world that sustains us and value the natural resources that we all share. Just around the corner there's a new bird or wildflower waiting to be discovered, and a new community of people in a corner of the state that you haven't visited. We hope the Great Wisconsin Birding and Nature Trails will take you there.

Susan Foote-Martin is the Great Wisconsin Birding and Nature Trail Coordinator for DNR's Bureau of Endangered Resources.

In the know: a few birding terms,
a few facts
Irruption: when a natural population undergoes a sudden upsurge in numbers, especially when natural ecological balances and checks are disturbed

Diurnal: hunts during the day

Nocturnal: hunts during the night

Vole: Eastern meadow (Microtus pennsylvanicus) and southern red-backed voles (Clethrionomys gapperi) are the favorite food item of northern owls. These small mammals have amazing reproductive capacity. They are like lemmings in that local populations can vary from one animal to thousands per hectare on a three- to four-year cycle. When vole populations peak, owls feed on nothing else. Great gray owls can eat six to eight voles per day.

GREAT GRAY OWL (Strix nebulosa)
HABITAT: Forested habitats throughout its range. In far North America, it frequents stunted coniferous forests along the edge of the Arctic treeline and spruce and tamarack muskeg forests further south.

RANGE: Found from Alaska across Canada, down the northern Rocky Mountains to Northern Minnesota. It is also found in northern Europe and Asia.

DESCRIPTION: One of the world's largest owls, it is dark gray overall interspersed with bars and flecks of light gray and white. The owl appears to be very bulky because of its dense, fluffy plumage, long wings and tail. A white "mustache" strip under its facial disk is broken by a black "bowtie." Its feet are heavily feathered and hidden from view.

SIZE: 24"-33" in length with wingspan up to 60" and weight up to 3.81 pounds.

DIET & FEEDING: Hunts mainly during early morning and late afternoon, especially during the winter, but will also hunt during other daylight hours and at night. Often seen perched on poles or fence posts along roadsides where it sits and waits. When the ground is covered with snow, it will hunt by hearing alone, often plunging into the snow to capture small rodents moving as much as a foot below the surface.

BREEDING & NESTING: Courtship involves feeding and mutual preening between mates and begins in midwinter. The male approaches the female, holding food in its beak, which is passed with both birds closing their eyes. The male selects possible nest sites and attracts its mate with calls. Several sites are inspected before she chooses the nest site. They primarily nest in abandoned stick nests of ravens, hawks or other owls. Great grays make modest nest repairs and line the nest with moss, deer hair or conifer needles. They also nest in tree snags or on the ground. Two to five eggs are laid and the young hatch in 28 days.

MORTALITY: In captivity a great gray can live to 40 years. Wild birds live shorter lives succumbing to starvation, predation by great horned owls, martens and wolverines, as well as people through shooting, road kill or power line electrocution.

NORTHERN HAWK OWL (Surnia ulula)
HABITAT: Boreal forests throughout its range.

RANGE: Boreal zones of North America and Eurasia.

DESCRIPTION: A crow-sized owl and diurnal hunter that acts and looks much like a hawk.

SIZE: Average 17" in length, with wingspan of 32" and weight of 11 ounces.

DIET & FEEDING: Eats mostly small mammals like mice and voles, but will eat birds. It will cache food, storing it to eat later.

BREEDING & NESTING: Begins nesting in April or May inside woodpecker holes or rotting trees. It also uses abandoned crow, hawk or squirrel nests. The bird lays 3-10 eggs that are incubated for 27 days.

BOREAL OWL (Aegolius funereus)
HABITAT: High elevations in spruce or fir forests, sometimes in lodgepole pine.

RANGE: Northern forests of North America.

DESCRIPTION: Round-headed with yellow eyes, white bill and white facial disks. It is often confused with the northern saw-whet owl as color and size is similar. Facial disk is reddish brown with a brown forehead streaked with white.

SIZE: 10".

DIET & FEEDING: Eats voles, lemmings and mice.

BREEDING & NESTING: Boreal nests in tree cavities or old woodpecker holes. It lays 3-7 eggs and incubates an average of 27 days.