Female Song in New World Wood-Warblers (Parulidae)

Abstract

Recent advances have revealed that female birdsong is widespread and multifunctional. Female song was likely ancestral among songbirds and persists in many lineages today. Nevertheless, many species lack female song, and researchers are interested in understanding the selective factors that promote and counter the persistence of this trait. Female song is associated with life-history traits including year-round territoriality, non-migratory behavior, sexual monochromatism, and monogamy. Most studies examining these relationships have looked at clades with a migratory ancestor and have found that gains of migratory behavior are strongly correlated with losses of female song (and duetting). Here, we ask if the reverse pattern exists: in a large clade of songbirds with a migratory ancestor, do losses of migratory behavior correlate with gains of female song and visual signaling traits? We investigated correlations between female song, migration, and dichromatism in 107 species of New World Warblers (Family Parulidae). All of these species are predominantly monogamous and territorial when breeding, 50 (47%) are migratory, 49 (46%) are monochromatic, and 25 (23%) show female song. On a robust genetic phylogeny maximum likelihood methods recover migration and monochromatism as the ancestral state in warblers. Female song is generally not reconstructed as present in any deep nodes of the phylogeny, suggesting that most extant species with female song evolved this trait independently and relatively recently. Gains of female song do not correlate with losses of migration. Losses of dichromatism do correlate with losses of migration. Thus, in this clade, visual signals are associated with sedentary vs. migratory lifestyles, but female acoustic signals are not. Our results show a different pattern from that seen in similar studies and support the hypothesis that losses, but not gains, of female song are driven by life history.

Sympatry drives colour and song evolution in wood-warblers (Parulidae)

“…We obtained recordings of singing male warblers from public repositories and personal collections (see electronic supplementary material, file S2 for recording information). We only tested male song because female song occurs in only a small subset of species (n = 25) [26]. For each species, we attempted to obtain five recordings that each contained one or more songs with high signal-to-noise ratio, no overlapping sounds, and no distortion, as determined aurally and by visual inspection of waveforms and spectrograms in Raven Pro software (v. 1.4; Cornell Lab of Ornithology, Ithaca, NY, USA).…”

Female in-nest chatter song increases predation

“…However, there is growing focus on the occurrence [3] and functions of female song [4], mostly using the perspective of life history and social selection theory. Female song is widespread and ancestral in songbirds, and females sing across 71% of extant species spanning 32 families [5].…”

Song function and territoriality in male and female White-throated Dippers Cinclus cinclus

“…Once thought to be rare, female song is now known to be widespread and evidence suggests that it is ancestral (Odom et al 2014). It is most prevalent in non-migratory species with year-round territoriality (Price et al 2008, Tobias et al 2016, and is closely associated with monogamy and sexual monochromatism (Najar & Benedict 2015, Webb et al 2016. However, studies of the function of song in females are largely restricted to duetting species (Hall & Peters 2008, Logue & Krupp 2016 and those that live in the tropics and Australasia (Slater & Mann 2004, Brunton & Li 2006, Odom & Benedict 2018.…”