The 2013-2014 Snowy Owl Incursion
Snowy Owl photo by Karen Lee Lewis
I haven't kept count, but I estimate that I have received over a hundred reports of snowy owls in our region this year. This is quite remarkable, but not entirely unprecedented. Mike Galas reminded me that, back in the 1980s during another incursion, we watched five snowy owls at once from the Bird Island Pier.
And ours are only a small measure of the thousands of snowies that have descended into the northeastern states. In fact they are being reported as far south as the Carolinas and even Bermuda.
This is, in any case, a major incursion. And the natural question arises. Why is this taking place?
But first, let's back up a bit. First consider some general information about these owls.
The snowy owl is our largest owl. Although the great gray owl, an even rarer visitor here, is a bit longer, the snowy owl outweighs it by 70%. We generally think of these birds as feeding on rodents, but it is twice the size of our common ducks and they more often serve as prey for the owls frequenting our waterfront. They have even been known to take Canada geese, which are among the few birds in our region that weigh more than the owls do.
This white owl is not an albino like the white squirrels and deer we occasionally see here. Unlike albinos, this owl has bright yellow eyes.
Its range is circumpolar. The species was named Bubo scandiacus by Carolus Linnaeus, the Swedish naturalist known for developing that binomial nomenclature. It is normally considered a permanent resident of the open tundra north of 60¡ latitude, thus over a thousand miles north of us here at about 43¡. That is about as far north as Key West is to our south. If you have been to Alaska to Churchill, you have been to snowy owl country.
It was formerly thought that these irruptions from their normal range were caused by low points in the cycle of lemming populations.
Lemmings are small rodents hard to distinguish from our meadow and red-backed voles. The range of two lemming species is restricted to the far north, but Wayne Gall once pointed out a lemming to me in a Southern Tier bog. A folk tale falsely enhanced by an early Disney film has them committing suicide in large numbers when they become overpopulated. Although the story has been dismissed, lemmings do migrate and some drown when they cross extensive bodies of water.
The theory that appears to fit these snowy owl irruptions more closely, however, is that they are caused by high points in the lemming population cycle. When this food source is easy to tap, the owls respond by having large families. Single females been known to lay as many as eleven eggs. Snowy owls are territorial and guard their ranges from other owls and this overproduction forces many, especially young owls, out of their normal territory. These are the birds reaching us here.
These younger owls have quite a bit of black barring among their white feathers. Only older males are all white. Some of them are also being seen here. These may be elderly owls that have lost their territories to younger, more robust birds.
Some of these birds from the far north become diseased here. Two afflictions rehabilitators are finding among them are aspergillosis, a respiratory mold infection that inhibits their breathing and can cause death and bumblefoot, a nasty swelling of the feet that can debilitate the bird.
The normal species of our region have developed immunities to these diseases but the owls lack those defenses. They don't get shots before they come south the way we do when we visit tropical countries.-- Gerry Rising
I hope you see at least one of these beautiful big white birds. They tend to find a location from which they can hunt and remain in that area. Birders have identified some of those places: on the outer breakwall at the Small Boat Harbor across from Tifft Nature Preserve and at these airports: Buffalo-Niagara, Niagara Falls, Batavia, Dunkirk, Mayville and Jamestown. If you visit one of these airports, expect to be checked by local police. I will post others and more specific directions on my twitter account.