Roger, Ken, et.al.
Fall movements of Common Nighthawks are complex and anybody who has
watched them intensively has found they can be moving in almost any
direction. Sometimes you'll see a group going south like good migrants then
a little bit later they are coming back north. I think there two basic
reasons for the complexity- first of all unlike other migrants, nighthawks
feed while they move and secondly the feed at night around artificial lights
at buildings, athletic fields, parking lots etc. Like you suggested Roger,
I think sometimes the flocks that aren't moving south late in the evening
are going to these nocturnal feeding areas. It has also been suggested that
early in the afternoon the birds move north where they gather in large
groups before heading south.
A recent study in Massachusetts where they watched from several
vantage points on the same evening showed nighthawks were moving in
different directions before gathering to fly south in specific corridors.
I suspect the same thing would happen in the mountains of SW Virginia.
A low tech way of solving the problem of nighthawk movement would be
have numerous observers in the same area watching at the same time.
For information on Project Nighthawk, a cooperative migration study go
to www.vicon.net/~ris/Home.htm
Paul Woodward
Fairfax City, VA 22032
grackling@xxxxxxxxxxxxxxxx
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