Thanks everyone for your help -- it does indeed appear to 
have been a Common Nighthawk; a life bird for me, so I 
didn't expect it at all.  If it hadn't been for MDOSPREY, it 
would have remained a mystery!

D

-- 
Derek C. Richardson, Ph.D. (CANTAB) ________
Astronomy, U Maryland, College Park MD 20742
Tel: Office 301-405-8786 Fax 301-314-9067 __
Home page: http://www.astro.umd.edu/~dcr/ __