Last night (actually early Fri. AM) made my first attempt to record 
night migrant flight calls and analyze  them with software from the Old 
Bird website and the Flight Call CD by Bill Evans and Michael O'Brien.  
Calls were recorded between 12AM and dawn when traffic and plane noise 
is quietest.  Only recorded 16 discernable bird calls before the predawn 
robins started calling.

I have a lot more questions than answers at this point.  3 of the 
recorded calls seemed to be a pretty good match (spectragraphically) for 
Song Sparrows. Not that exciting but its a start. Others recorded calls 
may not be clear enough to fully analyze but duration and frequency are 
suggestive of warblers.

I am hoping for better results as migration heats up. 

Birding even while I'm sleeping!

Andy Martin
Gaithersburg