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Ihaven’t kept count, but I estimate that I have received more than 100 reports of snowy owls in our region. This is quite remarkable, but not entirely unprecedented. Mike Galas reminded me that, back in the 1980s, 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 a major incursion. And the natural question arises: Why is this taking place?

But first, let’s 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 percent.

We generally think of these birds as feeding on rodents, but they are 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 degrees latitude, thus more than 1,000 miles north of us here at about 43 degrees. That is about as far north as Key West is to our south. If you have been to Alaska or Churchill, Manitoba, 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. 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 have been known to lay as many as 11 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. Rehabilitators are finding two afflictions among them – 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.

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 breakwater 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 other locations and more specific directions at twitter.com/GRNatureWatch.

email: insrisg@buffalo.edu">insrisg@buffalo.edu