An unidentified flight call

On August 27, 2010, around 4:30 am, I was in my yard in Kunkletown, Pennsylvania recording flight calls.  Most of the calls were of the common Swainson's Thrushes and Veeries, but there was one flight call that stood out.  One expert of the subject gave a possible identification, but I was curious what others thought.  The quality of the recording is not the greatest, so you may have to strain your ears to hear the call, but please take a listen if you are knowledgeable about nocturnal flight calls!  Thanks!