Thursday, December 29, 2011

Twenty-four! Snowy Owls!

Snowy Owl at Boundary Bay, Canada (Photos by Narca)

Boundary Bay near Delta, Canada, is hosting a Snowy Owl fiesta this winter. Twenty-four of the superlative creatures were visible from one spot on the day that our friend Jim Shiflett asked me to grab my passport and head north.

The Dyke Trail at Boundary Bay is accessible from 72nd Street.

Boundary Bay is renowned as a migratory stopover along the Pacific Flyway and as an Important Bird Area. Extensive mudflats, beds of eelgrass, and salt marshes support a rich mix of wintering birds and as many as 100,000 migrants, including many Dunlin and Western Sandpipers. And Snowy Owls like a dinner of Dunlin just fine, thank you.

Snowy Owls' feet are feathered all the way to their toetips, unlike the feet of birds from more temperate climes. This owl grooms those all-important foraging tools.

Snowy Owls feed high on the food chain. They mostly feast on small rodents like lemmings and voles, but readily switch to birds like gulls, shorebirds, and even other owl species. They are vigilant, although very few predators bother them: Arctic Foxes, dogs, the occasional Golden Eagle or Peregrine Falcon.

This year Snowy Owls are staging an irruption from their northern haunts and are penetrating regions far south of their normal habitats. Why do owl invasions occur? Some speculate that weather patterns are involved. In some years, irruptions may be caused by a failure of their lemming prey base, but this year's invasion appears to have a different cause. The Arctic experienced a huge boom in the lemming population this past summer, and many more young Snowy Owls are thought to have fledged than is the norm. A pair of Snowy Owls may not nest at all when the prey base is poor, but in a good year a pair can raise up to a dozen nestlings!

The winter food supply up north apparently isn't sufficient to support those extra youngsters, so many owls have moved south. This year's owl invasion is exceptional by any standards. It is even being called a "once-in-a-lifetime" irruption. Nebraska's tally is up to 58 individual Snowy Owls, and Wisconsin's count has surpassed 100. They are appearing in states as far south as Texas!

Will Arizona and New Mexico be adding Snowy Owl to their state lists? This is the year it might be possible! So watch for a big white owl in open country, in agricultural fields, or even on the roof of your local Target, the preferred perch of one owl in Washington this year. I guess that big, flat roof was as close to tundra as the owl could find in its immediate environs. Along the coast, the owls frequent beaches. A few years ago, Jim and I even saw a group in a small clearcut in a montane forest north of Seattle.

Those owls overwintering at a mecca like Boundary Bay should be able to find plenty of food, but, unfortunately, at least some of the owls are very hungry and growing weak. A few are finding their way to raptor rehabilitation centers.

My 6-year-old grandson already knew all about Snowy Owls––thanks to Harry Potter's Hedwig.

Adult Snowy Owls are whiter than young birds, and males tend to be whiter than females.

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