This morning, Sunday, December 5 at about 9:50 a CAVE SWALLOW visited
the marsh at the mouth of Accokeek Creek in Piscataway Park, Prince
George's County.  It flew in from the south, then for about ten minutes,
it circled the marsh making repeated close passes over our group
(Patuxent MOS field trip).  This gave us plenty of time to discuss field
marks and how to separate it from similar species and then to verify our
claims on subsequent passes.  Of course, I always want a better look at
a bird like this and we never saw it perch, but when we were all
reasonably satisfied with the identification, the bird headed toward the
East, upstream along the Potomac River.  Continued searching for the
next three hours did not relocate the bird.

As near as I can tell, this bird differed from other Cave Swallows
reported in the state so far this fall in that it was missing its
central tail feathers giving it a heart-shaped rather than square tipped
tail.  This may make it possible to speculate about their movements
within the state if a similar bird is located later this month. 
Otherwise, it was typical.  From above, it was dark with a light, orange
rump.  From below, it had dark wings and a gray body (not the gleaming
white of a tree swallow) and it had a buffy throat.  I did not note any
of the throat color on the bird's flanks.  From the side, its light face
contrasted with its dark cap with a sharp border between the two at
roughly the level of its eye.  I never saw it's light forehead, but I
also never had a view of the bird from above while it was approaching.

This was a state bird for everyone in the group and I believe it is a
first county record.

Otherwise, the trip was rather uneventful.  But nobody complained.

Dave
-- 
David Mozurkewich
Seabrook, PG, MD
mozurk (at) bell atlantic . net