Date: 8/27/20 10:34 pm
From: Paul Sullivan <paultsullivan...>
Subject: [obol] Re: Swift feeding frenzy
Back about 1990 in Pendleton. I saw Vaux Swifts nearly stalling in flight to
snap off small twigs from dead trees to use in building their nests.

Paul Sullivan

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[obol] Swift feeding frenzy
• From: Mark Rudolph <woodenappleturner@xxxxxxxxx>
• To: obol@xxxxxxxxxxxxx
• Date: Thu, 27 Aug 2020 21:17:44 -0700
Obolists,

I observed a behavior of VAUX'S SWIFTS today that I had never seen before.
At about 6 o'clock this evening over our neighbor's property in the Santa
Clara area of Eugene, there was a swarm of swifts totaling at least 30
birds and likely more. They were constantly roiling around and through the
tops of two 60' tall cottonwood trees, one of which is mostly dead or
moribund.

They were engaging in what I would call "stall-out" gleaning as opposed to
the hover gleaning engaged in by other species. With the wind coming out of
the north, the birds would fly into the wind from the south and time their
momentum and trajectory such that they would briefly stall right at a twig
or branch, apparently grab a food item with their bill from the tree and
then drop to regain speed and maneuverability for full flight. The swarm
did this repeatedly for at least 20 minutes, and then, apparently, the
hatch was over as they suddenly left.

I've never observed swifts take a food item from a stationary object. At
least I'm assuming they were feeding because I never actually saw any
insects, although I was probably over 100' away. There were a few House
Finches, Goldfinches and Cedar Waxwings also apparently feeding while
perched in the tree. The Waxwings would occasionally sally out to grab
something out of the air.

It would be quite the feat to figure out their built-in air traffic control!

Rudi


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