OK, here goes. Wacko theory No. 8,634.
Much of the eastern United States suffered some heavy winter weather this year, largely blamed on something called the polar vortex. That is a combining of elements involving the jet stream the positioning of high pressure centers in the cold north and warmer weather far offshore to the south. In my limited knowledge I don't think it's fair of me to explain it much beyond that. However there will be links below to places that will.Earlier in the winter, in November and December, people began spotting snowy owls way south of their usual habitat. Normally they nest in Arctic regions and migrate south for the winter but generally stay north of 60 degrees latitude. Anchorage, Alaska is at about 60 North. This year there were sightings throughout the midwest and as far east and south as Virginia. It struck me that these two events might have something in common.
I remember suggesting to one friend she overlay a map of the vortex onto a map owl sightings, but I never heard back. So, today I gave it a try and look what I came up with. The map on the left below is of the vortex; the one on the right is snowy owl sightings in November and December. Coincidence? Ha, I don't think so. Of course there are exceptions but it sure looks like the snowy owls congregated just where the vortex was gong to show up later.
 |
| One blast from the polar vortex on AccuWeather. |
 |
| Snowy owl sighting reports on eBird. |
Years ago I read an article in Sports Illustrated magazine written during the construction of the trans-Alaska pipeline. In it the author wrote of his fascination with bananas on a dining hall table on the Arctic Coast of Alaska. He noted that in nature when an animal appears far outside its normal habitat, it's an indication the herd is in trouble. And then he's looking at humans and bananas in the Arctic and wondering if our herd was in trouble.
Were the owls such a warning? Is the snowy owl in trouble for some reason? Was there a low point in their normal prey species? Were they just trying to be friendly alarmists to warn people of the coming harsh winter? What else could be going on? One would take a whole new wacky theory and I am only good for one a day. But consider this, Alaska is in the weather path for winds to bring radiation from Japan. Ponder that one for a while. Meanwhile I am sticking with the owls simply going where they were most comfortable, and willing to go so far as to guess they have some indicator that helps them anticipate what winter is going to do and they act accordingly.
The point here, though, is not the speculation about why it happened or theories about motivation. The point is simply the observation that snowy owls showed up ahead of time in the same areas where the polar vortex later brought its storms.
But we have a warning for those folks on the East Coast. We are going to be wanting our owls back, and soon.
A BIT OF AN UPDATE: Some comments have shown up, several saying the change in migration is due to a change in prey species. One said voles were down in the Arctic while another blamed a decline in the lemming population. That makes sense. That, however doesn't change the basic premise pointing out the correlation between the owl migration and the location of the polar vortex. Perhaps it's the lemmings or voles that signal the change in weather pattern. There a couple of new links to articles about the phenomenon below.
ANOTHER UPDATE: That snowy owl a commenter on here mentioned, the one who was rescued after it was hit by a bus in Washington, D.C., was scheduled to be released today (4/19) in northern Minnesota. Here's that story. There were other rescues, too, at least two, one in Cleveland and another in Portland, Oregon.
Graphic credits: Polar vortex: Accuweather.com; owl spottings: eBird.com; snowy owl photo: Wikkipedia
Another version from Alaska Dispatch News 12/10/16
It's happening again in 2015
Audubon magazine article on the snowy owl irruption
New York Times: Snowy owl a harbinger of climate change?
Snowy owl
Snowy owl migration 2013, eBird
NASA animated depiction of the winter's polar vortex
What's a polar vortex?
I read there was a bumper crop of baby snowy owls this year. This year one of the southern venturers found himself a perch on an awning on K Street in DC. Unfortunately while swooping down to catch a rat, the owl was hit by a city bus. But happy ending, he was taken to the zoo, treated and will be released back into the wild. I guess he will have to decide then if he is for the North or the South.
ReplyDeleteWe had the snowy owls here as well...
ReplyDeleteBack in the fall, when the local farmers sent ducks off to process the butchers noted that ALL the birds had huge layers of fat around the muscles, which they believed would mean a very cold winter...
I also found a wooly bear this fall with no stripe, all brown...