Losses of female song with changes from tropical to temperate breeding in the New World blackbirds

Abstract

Birds in which both sexes produce complex songs are thought to be more common in the tropics than in temperate areas, where typically only males sing. Yet the role of phylogeny in this apparent relationship between female song and latitude has never been examined. Here, we reconstruct evolutionary changes in female song and breeding latitude in the New World blackbirds (Icteridae), a family with both temperate and tropical representatives. We provide strong evidence that members of this group have moved repeatedly from tropical to temperate breeding ranges and, furthermore, that these range shifts were associated with losses of female song more often than expected by chance. This historical perspective suggests that male-biased song production in many temperate species is the result not of sexual selection for complex song in males but of selection against such songs in females. Our results provide new insights into the differences we see today between tropical and temperate songbirds, and suggest that the role of sexual selection in the evolution of bird song might not be as simple as we think.

Female Song in New World Wood-Warblers (Parulidae)

“…This is in accordance with other studies of life history correlates of migration in parulids (Cardoso and Hu, 2011;Simpson et al, 2015) and other birds (Hamilton, 1961;Hofmann et al, 2008;Price, 2009;Price et al, 2009). There are two major (and not necessarily mutually exclusive) hypotheses attempting to explain widespread dichromatism in migratory species.…”

“…A recent surge of interest in this topic has supported the idea that female song is associated with life-history traits that are common in tropical areas, including yearround territoriality and/or non-migratory behavior, sexual monochromatism, carotenoid dichromatism, and monogamy (Malacarne et al, 1991;Garamszegi et al, 2007;Benedict, 2008;Price, 2009;Price et al, 2009;Logue and Hall, 2014). In particular, gain of migratory behavior is strongly correlated with loss of female song (including duetting; Price et al, 2009;Logue and Hall, 2014).…”

“…The New World blackbirds (family Icteridae) are the beststudied group in regards to the life history correlates of female song (Hofmann et al, 2008;Price, 2009;Price et al, 2009). Barring the basal meadowlark clade, the ancestor of the rest of the New World blackbirds is inferred to have been a sedentary, monochromatic species with singing females.…”

“…In particular, gain of migratory behavior is strongly correlated with loss of female song (including duetting; Price et al, 2009;Logue and Hall, 2014). "Migration" may be best thought of not as one trait, but as an attribute that represents an amalgam of traits (navigational abilities, flight behavior, etc.)…”

Migration and the evolution of duetting in songbirds

“…Evidence for less similar sex roles in migratory species includes the links between migration and high testosterone levels in males [35], and the absence of song and colourful plumage in migrating females [18,36].…”