A Russian invasion in Gloucester

January 8, 2008 12:36 PM Email| Comments (0)| Text size – +

(Phil Brown photo)

A slaty-backed gull at Niles Pond in Gloucester in late December. The last sighting was about five days ago.

By Martin Finucane, Globe Staff

The Massachusetts birdwatching community is all atwitter after the recent sighting of several slaty-backed gulls in the state, birds that normally make their homes thousands of miles away in Siberia and Japan.

"It's always a thrill to find a bird that rare," said David Sibley, a Concord bird expert who spotted the bird at Jodrey Fish Pier in Gloucester on Dec. 23. "There’s something really special about that feeling of discovery."

Sibley saw the bird at about noon that day, narrowly beating out another bird expert, Wayne Petersen, who sighted one on Coast Guard Beach in Eastham an hour later. Later, others sighted another slaty-backed gull in Gloucester, bringing the grand total to three.

Sibley said the slaty-backed gull can be distinguished from the gulls normally seen around Massachusetts by its dark gray back, the brown streaking on its head, an extra splash of white on its wingtips, its pink legs, and its slightly different head and wing shape.

The bird normally makes its home in northeastern Asia and it can also be found in western Alaska. But it started to pop up in the lower 48 states about 20 years ago, Petersen said. It has now been sighted as far south and east as Florida.

Petersen said it's not clear why the gulls are being sighted in more places. One reason could be that birdwatchers are simply using better binoculars and better able to identify them.

But he also said it's possible that the birds are looking for elbow room. Gulls, in general, are a successful bird and their populations have been on the rise, he said.

For slaty-backed gulls, "it seems there is a subtle but increasing tendency to show up in places way away from where they should be. It could be we’re sort of on the front end of a trend," Petersen said.

"This could be the beginning of the invasion of the slaty-backed gull," said Sibley.