Snowy owls have migrated south into Montana and across the nation's northern tier this winter, showing up in large numbers around the Great Lakes as well as the East and West coasts.
"So far we're getting lots of reports," said Amy Cilimburg of Montana Audubon. "It seems like it's going to be a big year."
It's not unusual for the big white predators to fly south from the Arctic in search of food, especially yearling males, said Denver Holt of the Owl Research Institute in Charlo. What is different this year is the widespread sightings of the birds.
"Coast to coast, people are seeing a lot of animals," Holt said. "What it all means is hard to say."
One snowy owl was shot by federal Wildlife Services in November after it couldn't be flushed off the runway at Honolulu International Airport, according to online reports. The snowy owl was the first one recorded so far south.
Snowy owls, or Bubo scandiacus, are easily identifiable because of their large size — 2 feet or more tall with wingspans of almost 5 feet — as well as their brilliant white color. Only older males are almost completely white. Otherwise, the birds maintain black barring or flecking.
Holt said it's possibile that the birds disperse south after successful breeding seasons in order to spread out the competition for a finite food source. Or they may be facing a shortage of food or harsh weather.
In the Arctic, where the birds nest and breed, they eat mostly lemmings, a small, mouselike animal that lives in the tundra. One study found that snowy owls eat three to five lemmings a day. They will also eat other small animals, such as rabbits and birds.
Snowy owls can be easily spotted on Montana's currently snow-sparse landscape as they sit atop fence posts, telephone poles or rises on the ground. From these perches, the birds scan the countryside with their bright yellow eyes, looking for prey. Although the owls will hunt during the day, they seem to be most active around dusk.
On the move
The owls migrate south in November. In Montana, they've been sighted from Kalispell in the northwest to Plentywood in the northeast and as far south as the Crow Reservation south of Billings. Chuck Carlson, a retired biologist, has seen and photographed them near his home in Fort Peck.
"We usually see at least one a year," Carlson said. "But this year is a pretty good one for snowies. It's an invasion year."
The white owls started showing up near Fort Peck in mid-November, he said. He's counted four so far.
"They seem to be quite skittish around here," Carlson said.
That's not always the case, though. In 2005-06, there was a large influx of snowy owls into the Mission Valley in northwestern Montana. Hundreds of people flocked to the area to watch and photograph the birds, said Holt, who conducted a study on the irruption -- defined as an incursion of birds that don't normally winter in the area.
Holt's research showed that the owls were feeding on voles populating the Mission Valley at the time. By March, most of the owls had flown back north.
"It was just amazing how many people were interested in all these owls," Holt said. "Owls in general are one of the most widely recognized groups of birds in the world. And there's just something about white animals that people admire. So people are just in awe over big white owls."