Nick Mason recently published part of his MS thesis in the Biological Journal of the Linnean Society on tanager song and habitat. In this paper, Nick looked for correlations between body size, habitat, and vocal characteristics across the evolutionary tree of tanagers. In particular, Nick was interested in testing ‘the acoustic adaptation hypothesis’ which says differences in vegetation structure impose different selective pressures on song evolution. For example, birds that sing in more closed habitats should have lower vocal frequencies. Since tanagers are the largest family of songbirds, they would be a good place to look for such correlations. However, Nick found that habitat was only correlated with a few song characters. Instead, body size plays a more important role in shaping the evolution of song differences among species. Nice paper Nick! Here is the full citation:
Mason, N.A.* and K. J. Burns. 2015. The effect of habitat and body size on the evolution of vocal displays in Thraupidae (tanagers), the largest family of songbirds. Biological Journal of the Linnean Society 114: 538–551. For pdf, you can go to the journal’s web site or just send an email request to firstname.lastname@example.org.