Male House Finches with Elaborate Songs have Higher Reproductive Performance

For territorial animals, vocal signals can play an important role in both territory defense and mate attraction. The elaborate songs of many male songbirds (order: Passeriformes) serve these dual functions (Catchpole & Slater 1995; Collins 2004). In non-territorial songbirds, however, the adaptive significance of song is poorly understood. Sexual selection through female choice is expected to be the primary force driving the elaboration of male songs in non-territorial animals, but studies exploring male song characteristics and male reproductive performance in wild, non-territorial songbirds are scarce. House finches, Carpodacus mexicanus, defend no resources other than their mates and thus are considered to be non-territorial (Hill 1993, 2002). Each male house finch has a repertoire of syllables (Mundinger 1975; Bitterbaum & Baptista 1979; Pytte 1997) which are combined to produce impressive songs described as rambling, hoarse warbles (Thompson 1960; Hill 1993). Male song structure varies between eastern and western populations: eastern house finch males have repertoires of song types composed of syllables sung in a stereotyped order Correspondence Daniel J. Mennill, 401 Sunset Avenue, Department of Biological Sciences, University of Windsor, Windsor, Ontario, Canada N9B3P4. E-mail: [email protected]