Saturday, October 28, 2014
Republican American – Oct 28 2:16 AM
Copyright © 2014 Republican-American
Tree swallows were streaming by at a brisk pace. I estimated more than 4,000 over the first few hours after dawn on Monday, clearing out of New England on a brisk northwest wind.
My primary task was counting migrant hawks at Lighthouse Point in New Haven, and there were plenty of them, too. The day’s tally topped 600.
I wasn’t watching the swallows too closely, since at this time of year every one was likely to be a tree swallow. But I happened to be looking in the right place at the right time when one of Connecticut’s most interesting bird stories flashed before my eyes.
The light was just right and the binoculars in the right position to get a quick but good look at a single cave swallow with all those tree swallows.
Less than 30 years ago, the cave swallow was unknown in Connecticut and almost non-existent north of Mexico or the Caribbean. If you wanted to see one you had to go to Carlsbad Caverns in New Mexico or a few limestone caves in west Texas. They really were cave swallows.
Then something unusual happened. The southwestern race somehow figured out how to exploit man-made culverts as nest sites, and the Texas population exploded. In the 1980s a few cave swallows were seen at Cape May, N.J., and since then a pattern of late fall appearances in the Midwest and Northeast has developed.
Each year now, usually in November, a weather system sweeping from the southwest to the northeast deposits cave swallows around the Great Lakes. From there the next strong cold front sends them hurtling southward.
This mechanism has become so reliable that Connecticut birders can just about predict to the day when a noticeable flight of cave swallows will hit places such as Lighthouse Point or Hammonasset Beach State Park in Madison.
The bird I saw Monday was a little ahead of the curve, but we’ll probably get cave swallow flight sometime between now and the middle of November.
Reach Greg Hanisek at ghanisekrep-am.com
