There is considerable discussion of these pre-dawn calls by
VIOLET-GREEN SWALLOWS in Arthur Cleveland Bent's "Life Histories Of North
American Flycatchers, Larks, Swallows, And Their Allies", published in
1942. Under courtship he wrote:
Mr. Rathburn (MS.) records in his notes his experience with
early-morning flight songs, heard long before sunrise, of the
violet-green swallow, which appear to be part of the nuptial performance.
I quote directly from his notes as follows: "June 5, 1923. This morning I
arose at 1:45 to make some notes. It is mild, the stars shine
brilliantly, and at this hour there is no moon. 2:26 a.m. The first notes
are heard coming from a violet-green swallow. Within the next two
minutes, notes from a number of the swallows are heard, the birds flying
rapidly around. At this time, faint traces of the dawn show in the sky at
the northeast, but stars are very bright as it is clear. At 2:33 a.m.,
the violet-greens are heard on every side, their notes increasing within
the next five minutes, the birds seeming to be at quite a low height. As
morning light slowly grows, the calls of the swallows are even stronger;
interjected at times were some musical notes heard only occasionally at
the time of the nuptial period. 3:08 a.m. The notes given by the swallows
are now becoming less. At this time, the stars are faint. 3:11 a.m. The
swallows have ceased calling, having flown about for about 45 minutes."
I recently had a phone call from some one who upon hearing these
calls wanted to know if they might be a form of echo location. Has there
been any studies on whether this might be happening? How do swallows
locate their prey in the dark?
Wilson Cady
Washougal, WA.
gorgebirds at juno.com
360-835-5947 gorgebirds at juno.com

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