Fish & Wildlife
пятница, января 27, 2012
By Diane Tipton, Montana Fish, Wildlife & Parks Statewide Information Officer
Snowy owls are putting on a real show for Montanans this winter. These stunning white owls nest and breed in the Arctic where they mainly eat lemmings, a small, mouse-like mammal. Their winter movements, called irruptions, bring them into southern Canada about once every four years—and sometimes even as far south as the United States.
For the past three months, snowy owls have been seen frequently across northern Montana generally in open, windswept fields. Watch power line poles, rock piles or anything with a little height.
Experts at the Cornell Lab of Ornithology in Ithaca, N.Y., and David Sibley, of the Sibley Guides fame, seem to agree that this year's irruption likely relates to the boom and bust cycles of lemmings. A bountiful lemming population last summer enabled nesting snowy owls to feed and fledge more than twice the usual young. In turn, burgeoning owl numbers reduced the lemming supply going into winter. According to Sibley, lower ranking birds losing out to the competition began to deposit fat and feel a natural urge to head south for better hunting. The lucky ones will survive the journey to return to the arctic in the spring.
Though they prey on small mammals, including voles, there is nothing small about this owl. It can be two feet or more in height with a five foot wingspan. Its size and sparkling white feathers highlighted with dark bands create an unforgettable image—at least one Montana duck hunter will never forget it.
Ron Selden, with Montana Fish, Wildlife & Parks in Glasgow, was duck hunting in Phillips County when he shot a duck that dropped onto the ice about 30 yards away from his hunting cover.
"When I stood up to retrieve my duck a couple of minutes later, I was shocked to see that a snowy owl had quietly landed and was rapidly and very avidly tearing into it," Selden said. "In surprise I yelled "HEY."
"Equally surprised, it looked at me, then grabbed my duck and flew off," Selden said.
The duck was too heavy though, or maybe too unbalanced of a load. The snowy owl dropped the drake onto a patch of shallow, open water about 100 yards from shore.
"The owl flew on and I was left to wade out through the deep, semi-frozen muck and water to retrieve the duck," he said. "It wasn’t until I got home and started cleaning my birds that I saw how the owl had worked over that drake. It was shredded and barely edible."
That is likely one of the closer snowy owl encounters this winter, but experts say sightings may continue through February.
"I have seen about 25 or 30 so far from Opheim over to Plentywood and down to Medicine Lake," said Ryan Williamson, FWP Upland Game Bird Enhancement Program biologist in Outlook."Some owls are almost solid white and some are very gray looking."
In one weekend alone Williamson spotted seven or eight snowy owls in Daniels County.
Birders say there are likely many of the large white owls as yet unreported.
"The number of sightings is absolutely tied to the number of people out looking," said Dan Casey of the American Bird Conservancy in Kalispell.
Casey said he has no idea of how many of these snowy owls will find sufficient nutrition to survive here and return to the Arctic.
"Snowy owls arrive stressed to various degrees from the travel and can be vulnerable if local prey populations dwindle rapidly," he said. "If you see a snowy owl, give it a wide berth and avoid causing it to hop or fly from place to place, unnecessarily burning energy."
Birders are encouraged to report snowy owl sightings to e-bird.com or to the Natural Heritage Tracker—online data collection sites. Or, go to the Montana outdoor birding website at http://pets.groups.yahoo.com/group/MOB-Montana/ to learn how many owls have been sighted and where. For more on snowy owls, go to the online Montana Field Guide.