Hey Sumner! I found it:
http://magazine.audubon.org/birdsongs/Chickadee--NorthAmerica.wav
http://en.wikipedia.org/wiki/Black-capped_Chickadee
It's the Black-capped Chickadee, and I nominate it for the position of "Official Team Bird".
If there are any dissenters I will fight them on the spot. This bird's the move.