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Tuesday, January 31, 2012

Millennial Mysteries: The Answer to Arctic Owls Flying South and Other 2012 Arctic Bird Oddities?

Painting of Snowy Owl (1996) © Kim Hunter.

Never seen a magnificent Arctic Owl? Depending on where you live, now could be your chance. I recently mentioned strange Canada Goose migrations. Snowy Owls are currently migrating hundreds of miles far south from Arctic climes - in a way not seen in many decades, such that some observers are calling the phenomenon a 'wildlife event.'

A once-in-a-lifetime sight: "The Missouri Department of Conservation said no one has seen a snowy owl this far south since 1974." A Snowy Owl in northern Jasper County, Missouri, January 2012.  Image Source: Carthage Press.

The birds' winter range normally does not extend south of the Great Lakes in North America, or south of Russia in Central Asia. But they have been spotted quite far south all over the United States.  Unlike most owls, they are active during the day, making sightings more likely.  Unused to human environments beyond their Tundra habitat, they are stressed and confused and getting into trouble.  One owl showed up at the airport in Hawaii, and startled staff shot it.  One owl in Kansas City was killed when it flew into a train.  Another is being cared for at Washington State University in Seattle after it collided with a car; the owl is being kept on a tub filled with ice with a fan blowing on him, which you can see hereYahoo News reported on 28 January:
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.

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.

"What we're seeing now -- it's unbelievable," said Denver Holt, head of the Owl Research Institute in Montana.

"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. ... 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.
For further reports on the Snowy Owls from MSM outlets and local bird-watching societies, go here, here, here, here, here, here, here, here, here and here.  The Great Backyard Bird Count expects to record this irruption.  The Bird Count is an annual event in which people across North America submit reports on the numbers and types of birds they see in their backyards.  This information helps keep track of phenomena such as Arctic birds flying further south than usual. The Great Backyard Bird Count starts February 17 and runs until February 20 (to participate, go here).  Last year, 11.5 million birds were counted by amateur bird-watchers in the Bird Count, which also runs a photo contest and gallery.

Although this owl irruption is a really popular Internet story, no one has bothered to ask (at least, as far as I could see) whether other Arctic avian species which normally stay within a certain northern range are flying south as well. This is where this seemingly isolated event gets interesting.

A parliament of Arctic Owls in British Columbia's Boundary Bay (7 January 2012) © Sandy Milliken. Image Source: via The Spokesman-Review.

Birdwatchers in the UK report unusual flocks of Arctic Kumlien's Gulls, Ross's Gulls and Iceland Gulls - all are high Arctic species - flying south: "This [Ross Gull sighting] comes on top of one of the largest influxes of Kumlien's and Iceland Gulls ever known in the region, including no less than 83 individuals in Stornoway Harbour on Lewis (Outer Hebrides) alone."

Puffins have also been surprising bird-watchers in places slightly further south than usual, although not in huge numbers.  Several reports from Montreal suggested that one Puffin had become seriously disoriented: Montreal, Canada.   Puffins spotted: in Suffolk, UK; in Essex, UK, also here; and Boundary Bay, British Columbia, Canada

Another Arctic bird species that has some unusual information concerning it this year is the Snow Bunting.  The Canadian blogger at Ruthven Park Nature Blog, who monitors Snow Buntings, has been alarmed to find that he can barely find any Buntings where they would normally be at this time of year; he is writing from Ruthven Park, Ontario:
I don’t know any other way to put it: this season’s Snow Bunting banding has been a disaster. Consider the numbers: at this same date in 2010, we had banded 619 (total for the whole Winter – 985); at this date in 2011, we had banded 1,074 (Winter total – 2,844); so far this year we have banded only 33! And it’s not just us: David Lamble, who bands in the Fergus area and who banded just under 7,000 last Winter, has banded only 200 so far this season. So what’s going on?
The blogger, Rick L., hit upon something strange and explained it all thanks to Earth Labs (a collaboration between the Center for Science Teaching and Learning at TERC in Cambridge, Massachusetts and the Science Education Resource Center (SERC) at Carleton College in Northfield, Minnesota.)

2012: an extreme positive Arctic oscillation. Image Source: Wiki.

2012 is an abnormally mild winter, a result of a record shift in Arctic air pressure.  This winter features an extreme positive Arctic oscillation, which follows on two previous winters that were extreme negative Arctic oscilations.  What are Arctic oscillations?  Very roughly, they are sort of an Arctic counterpart to El Niño.  They involve the movement of air between the North Pole and areas to the south, propelled by changes in air pressure.  When the air pressure in southern regions is higher, the oscilation is called 'positive' and results in warm air moving north (hence a milder winter across much of the northern hemisphere), with the really cold air concentrated in the far north.  When the air pressure in the Arctic is higher, the oscilation is called 'negative' and cold air is distributed further south.

Thus, massive fluctuations in Arctic air pressure, possibly influenced by solar winds (see recent posts on unusually vibrant Arctic auroras here), are apparently affecting bird populations.

Huge shifts in Arctic air pressure, from negative in 2009-2011, followed by positive in 2012, the magnitude of which are also much higher than the previous 60 years.  Image Source: Ruthven Park Nature Blog.

Meanwhile, the 2012ers and other doomsayers have taken the owl migration as an apocalyptic sign: here, here, here and here.  One blog, The Celestial Convergence, sees the irruption as a precursor of disaster and some forum commenters think it has to do with Fukushima radiation.  The only connection I can see with Fukushima (latest on its many leaks here) regards shifting weather patterns and the corresponding spread of radiation.

2 comments:

  1. The actual explanation you've found is a lot more intelligent than the "oh it must be global warming" I get everywhere. -J

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  2. Thank you, although I am not sure why a warmer winter would lead to some species leaving the tundra (owls and arctic gulls) while others not (buntings). I concluded it must be related to their food supply, which is something mentioned in the original report.

    Also I wondered about changing wind currents and geo-magnetic shifts, which might additionally affect avian irruptions and migrations. As I said in an earlier post, Canada Geese were still leaving this area on **Christmas Eve** 2011. I have never seen that over the decades that I have spent the holidays here. I can't help feeling that the Arctic Owls are responding to a much larger phenomenon; I don't think global warming has anything to do with it - this was a sudden change from one year to the next.

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