Friday, September 16, 2011

VAUX'S MIGRATION


How many people can you fit into a Henry J?  Fourteen, if you are a teenager from the 1950′s. Jim and his school chum Al Penta spent time reminiscing about their high school antics for an hour over lunch. Al, in the biking costume, brought along his friend, Ed.  As we parted, Al told us about the Vaux’s (rhymes  with foxes) migration going on.

At dusk, we drove back to town and situated ourselves at the Frank Wagner Elementary School to watch thousands of Vaux’s Swifts get ready for bed. The second largest congregation of Swifts in North America have chosen this four foot square chimney to spend their nights.

Before the birds began their nighttime action, people gathered on the school lawn with their cameras and chairs. Peak time was Sept 2nd when 3455 swifts settled  into the chimney. The school has a camera mounted on the chimney and a monitor in a window where you can watch them snuggling in.

Swifts do not perch. They dig their claws into rough surfaces and cling. In a chosen chimney or hollow tree, they pack in like shingles,overlapping each other for warmth.

The school and Pilchuck Audubon Society supplied brochures, a story board  and docents to answer questions from watchers.

They began gathering near the chimney before dark, still darting about snapping up mosquitoes. The swifts  are leading their young from north-western Canada and Washington, to Central America and Venezuela.

Soon thousands of them were performing aerial maneuvers, mostly darting and circling, and re-circling. It makes you wonder how they can recognize their mates and young.

Vaux’s forage, eat, drink mate, court, and collect nesting materials while in flight. The picture showing a drinking swift gives you a clue why they like this area with its river and swampy mosquito breeding areas.

No one knows what signal begins their actual plunge into their chosen roosting spot. They move so swiftly, hence the name, you can barely see them enter, just a flutter of wings, then another circling as a new batch gathers for the plunge.

The numbers begin to thin. Sometimes they circle in one direction, then switch to another direction. They enter head first, then tail first. It seems peculiar, but they obviously know how to get into a small space. The birds are 4 to 5 inches long. At night they slow their metabolism to a near dormant state to conserve energy while sleeping.

We didn’t stay until the last swift disappeared down the chimney, but the docent told us that one night 3 single birds circled and circled as though they couldn’t find room at the inn. When they finally flew into the chimney, the crowd applauded. By the time we left, there were about fifty people watching.  The cumulative  count, as of Sept. 10th, was 33,546 .  Nature always provides a fascinating spectacle. At http://otrwjam.wordpress.com, on our mutual blog, you can see Jim's video of the Vaux's Swifts pouring into the chimney.

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