雪鴞從北極高飛向南作罕見的大規模遷移

"Unbelievable" Snowy owl mass migration.
“不可思議”雪鴞大規模移民
2012-01-28

雪鴞從北極高飛向南作罕見的大規模遷移
Snowy owls soar south from Arctic in rare mass migration
By Laura Zuckerman |
Reuters –
13 hrs ago
Translation by Autumnson Blog

SALMON, Idaho (Reuters) - Bird enthusiasts are reporting rising numbers of snowy owls from the Arctic winging into the lower 48 states this winter in a mass southern migration that a leading owl researcher called "unbelievable."
愛達荷州所羅門（路透社） - 雀鳥愛好者報告今年冬季來自北極的越來越多雪鴞，飛進美國 的下四十八州作大規模的南部遷徙，一位領先的貓頭鷹研究員稱之“令人難以置信。”
Thousands of the snow-white birds, which stand 2 feet tall with 5-foot wingspans, have been spotted from coast to coast, feeding in farmlands in Idaho, roosting on rooftops in Montana, gliding over golf courses in Missouri and soaring over shorelines in Massachusetts.
數以千計的雪白色雀鳥，企立有二英尺身高與五英尺翼展，已從海岸到海岸被發現，在愛達荷州的農田餵飼，在蒙大拿州的屋頂棲息，在密蘇里州的高爾夫球場滑翔和在馬薩諸塞州的海岸線上空翱翔。
A certain number of the iconic owls fly south from their Arctic breeding grounds each winter but rarely do so many venture so far away even amid large-scale, periodic southern migrations known as irruptions.
某一個數量的標誌性貓頭鷹每年冬天從他們的北極溫床往南飛，但罕有見到那麼遠這麼多的風險，即使是中大型、定期的南部遷徙名為闖入。
"What we're seeing now -- it's unbelievable," said Denver Holt, head of the Owl Research Institute in Montana.
“我們現在所看到的 -- 是難以置信，”蒙大拿州的貓頭鷹研究所負責人丹佛霍爾特說。
"This is the most significant wildlife event in decades," added Holt, who has studied snowy owls in their Arctic tundra ecosystem for two decades.

Holt and other owl experts say the phenomenon is likely linked to lemmings, a rodent that accounts for 90 percent of the diet of snowy owls during breeding months that stretch from May into September. The largely nocturnal birds also prey on a host of other animals, from voles to geese.

An especially plentiful supply of lemmings last season likely led to a population boom among owls that resulted in each breeding pair hatching as many as seven offspring. That compares to a typical clutch size of no more than two, Holt said.

Greater competition this year for food in the Far North by the booming bird population may have then driven mostly younger, male owls much farther south than normal.

Research on the animals is scarce because of the remoteness and extreme conditions of the terrain the owls occupy, including northern Russia and Scandinavia, he said.

The surge in snowy owl sightings has brought birders flocking from Texas, Arizona and Utah to the Northern Rockies and Pacific Northwest, pouring tourist dollars into local economies and crowding parks and wildlife areas. The irruption has triggered widespread public fascination that appears to span ages and interests.

"For the last couple months, every other visitor asks if we've seen a snowy owl today," said Frances Tanaka, a volunteer for the Nisqually National Wildlife Refuge northeast of Olympia, Washington.

But accounts of emaciated owls at some sites -- including a food-starved bird that dropped dead in a farmer's field in Wisconsin -- suggest the migration has a darker side. And Holt said an owl that landed at an airport in Hawaii in November was shot and killed to avoid collisions with planes.

He said snowy owl populations are believed to be in an overall decline, possibly because a changing climate has lessened the abundance of vegetation like grasses that lemmings rely on.

This winter's snowy owl outbreak, with multiple sightings as far south as Oklahoma, remains largely a mystery of nature.

"There's a lot of speculation. As far as hard evidence, we really don't know," Holt said.

(Editing by Steve Gorman and David Bailey)
http://news.yahoo.com/snowy-owls-soar-south-arctic-rare-mass-migration-175336821.html