Purple Martin (Progne subis)
Croak Song: Rich, low pitched gurgling notes, usually ending with a series of clicks. This song is given by males during courtship (Brown 1997).
Purple Martin croak song, June 20, 2009, Horicon Marsh, Dodge County, Wisconsin.
Brown, Charles R. 1997. Purple Martin (Progne subis), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/287 doi:10.2173/bna.287