Northern Owl Irruption 2004-2005
Article Date: 2005-02-23 Source: http://www.mercurynews.com
By Chris Niskanen
ST. PAUL, Minn. - When he drove from Roseville to Aitkin County recently, Don Snow had the bird-watching experience of a lifetime: He counted more than 20 great gray owls along the way, 19 more than Snow had seen his entire life. He also saw the ugly side of the current owl invasion: At least six great gray owls lay dead along the highway, killed by collisions with vehicles. "It's a shame to see them slaughtered like that,'' Snow said. "People should really slow down when they see them along the road."
Snow and thousands of other bird enthusiasts are witnesses this year to perhaps the most unusual avian phenomenon ever recorded in Minnesota - a mass invasion of northern owls that typically dwell in the deep forests of Canada.
The owl invasion, also known as an irruption, began in far northern Minnesota but last week reached the central part of the state, with a few owls appearing in the Twin Cities and as far south as Iowa.
The biggest feathered attraction are the great gray owls, one of the world's largest owls, measuring about 2 feet tall with a 5-foot wingspan, but rare Northern Hawk Owls and diminutive Boreal Owls also are pulling birders into the state. The binocular-toting tourists are coming from Europe and both U.S. coasts to see the owls, say bird enthusiasts. "It's not only the biggest irruption of owls ever, it's also the biggest irruption of owl watchers,'' said Steve Wilson, a Department of Natural Resources biologist based in Tower.
Wilson has the unfortunate duty of counting the dead as well. Scientists believe the nomadic owls have left Canada because of a lack of prey, mainly voles and mice. While some have starved to death in Minnesota, vehicles have killed many others. The slow-flying owls are attracted to open areas, such as roads, to hunt their prey.
Wilson said the official total for great Gray Owl deaths is 226, but many more probably haven't been recovered. Citizens, wildlife officers and some volunteers have turned the owls over to the DNR, which in turn is making sure the dead owls are used for science or education. The birds are either mounted or preserved as study skins.
The Chicago Field Museum of Natural History recently picked up 110 dead great gray owls for its collection, and great grays have been donated to the Bell Museum at the University of Minnesota, the Carnegie Museum in Pittsburgh, the University of Kansas and St. Olaf College. Schools in northern Minnesota and nature centers throughout the Midwest have requested birds for display. "The educational opportunities that will continue for years (are) one of the silver linings of the significant mortality that we're seeing,'' Wilson said.
Great gray owls hunt during the day and are naturally docile, often allowing viewers to approach within a few feet. The opportunity for close-up viewing of the birds has spread through the Internet and the media. After recently announcing great grays were spotted at Wild River State Park, officials saw a spike in attendance last weekend. "With the slow ski season, it has definitely brought more people into the park than would normally be here,'' said Shawn Donais, who manages the park near North Branch. "About 80 percent of our visitors last weekend were owl-watchers."
Bird-watchers first noted the invasion last fall along the North Shore. When an ice storm swept through the North Shore in January, great grays were seen flying through downtown Duluth and heading south. "It was quite dramatic, like something out of a Harry Potter movie,'' Wilson said.
He said the birds are "highly nomadic" when it comes to seeking prey, so it wasn't surprising they soon were concentrated farther south in Aitkin, Pine and Carlton counties, where the snow wasn't as deep. That allowed the birds to plunge down and catch small mammals. Scientists believe the birds were moving south at about 25 miles a day. More recently, the owls have been seen as far south as the Twin Cities, and one was reported recently in Iowa. Although some have died of starvation, Wilson said scientists have noted many birds killed by vehicles were in good body condition, suggesting they had found food in Minnesota.
Kim Eckert of Duluth, a professional bird guide, said he has led numerous owl tours since the invasion began. "I know of people coming from Florida, Texas, California, the East Coast and a few from England,'' he said. "We don't know how many have come from out of state, but I'm guessing at least half the states have been represented. This invasion is way above what any of us have ever seen before." The Minnesota Ornithologists Union has been on the front edge of tracking the owl's migration through the state, said union president Mark Alt. He said the organization has devoted a Web site to the invasion and has offered ethical viewing tips to birders. "We had some slob birders who were acting very poorly,'' he said. "Things like setting up spotting scopes in people's front yards without permission. It was causing some people to flip out." Alt said it's important for birders to behave properly in northern Minnesota and not to give the activity a bad name. "People are now starting to police themselves,'' he said. "It's gotten better."
Wilson said during the last owl invasion in 2000, it was considered big news if birders saw a handful of great gray owls in a day. "Now, we know of someone who saw 214 great grays in a day. (The invasion) is unprecedented in terms of intensity and scale."
During its Jan. 17 statewide census, the ornithologists union tallied 1,715 great gray owls, 300 northern hawk owls and 400 boreal owls, a number adjusted for duplicate sightings. In a normal winter survey, that number would be 35 great grays, six northern hawk owls and a single Boreal Owl.
Wilson said the invasion is now attracting many novice bird-watchers and wildlife enthusiasts, which means news of the owls has spread far and wide. The fascination with the owls hasn't surprised Wilson.
"These owls are the charismatic mega-fauna of the bird world,'' he said. "Plus, it's winter. People are probably feeling pretty cooped up. It's generated a lot of interest."
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