Uirapuru (Cyphorhinus arada VE-km67 19940712 S1 ATC) by Dean Frey
There are so many Creative Commons-licensed bird songs on the web now. This one is by Allen T. Chartier, recorded in Venezuela, 12-07-1994, found at this great website. Here's a lovely picture of the "Musical Wren" ("Uirapuru" is the Portuguese name, based on the Tupi "wirapu 'ru").
And here, for comparison, is the first part of Villa-Lobos's ballet Uirapuru. This recording is by the OSMSP, conducted by Rodrigo de Carvalho.
Uirapuru, by Villa-Lobos (clip) by Dean Frey