Swifts swallows and swiftlets

To: "Evan Beaver" <>, "birding aus" <>
Subject: Swifts swallows and swiftlets
From: "Ricki Coughlan" <>
Date: Tue, 7 Feb 2006 08:15:27 +1100
Hi Evan
These would almost certainly be Welcome Swallows. As well as being excellent flyers at altitude, these birds are excellent at employing "ground effect" with their rapid low level flights across playing fields. Of interest to note is that they are clearly more actively snapping up insects when the sun is behind them. With the sun behind them, their shadow runs along the ground before them. I have frequently noted this and have concluded that, like the Willie Wagtail*, they may well actively employ their shadow as a means of disturbing insects into motion before them.
Swifts may swoop low now and again, but definitely favour significantly greater altitudes than 10cm above playing field surfaces.
*Willie Wagtails use the shadows cast by their wings and tails to disturb potential prey into flight, which they then snap up. (I've noted this in my own studies for Uni as well as in another paper or two by other researchers. I can provide if you're interested.) If you've ever run across a field in the company of Willie Wagtails in the morning or afternoon, when your shadow is a little longer, they will freqently work alongside your shadow, right on its edge. I have even noticed "Willies" following the front line of the shadow cast by my car along the curb and eagerly snapping up prey which the shadow disturbed. . . Fanstastic stuff!
Ricki Coughlan
Lyrebird Tours
Sydney, Australia
p: +61 2 9453 2274
m: 0400 436 910
ABN 50 515 608 903
<Prev in Thread] Current Thread [Next in Thread>

The University of NSW School of Computer and Engineering takes no responsibility for the contents of this archive. It is purely a compilation of material sent by many people to the birding-aus mailing list. It has not been checked for accuracy nor its content verified in any way. If you wish to get material removed from the archive or have other queries about the archive e-mail Andrew Taylor at this address: andrewt@cse.unsw.EDU.AU