Song Dialects and Colonization in the House Finch, Carpodacus mexicanus, on the East Coast

Abstract

The songs of 155 banded and unbanded male house finches were sampled in a study of song variation along the SW coastline of Long Island Sound [USA]. Song variation occurs as a series of local song dialects, the birds in each dialect inhabiting an exclusive area a few kilometers on a side. Boundaries between adjacent dialects appear to be discrete, and a few hundered meters wide. Males with hybrid song repertoires may occur in the boundary regions. There was no significant yearly variation in the songs characterizing known individuals or their local population. The geographic distribution of dialects, the patterns of dispersal inferred from the banding records of 2 dialect areas, and the history of the early founder populations are discussed with respect to house finch colonization and the evolution of new dialects.