A female songbird out-sings male conspecifics during simulated territorial intrusions

Abstract

While birdsong is a model system for animal communication studies, our knowledge is derived primarily from the study of only one sex and is therefore incomplete. The study of song in a role-reversed species would provide a unique opportunity to study selective pressures and mechanisms specific to females, and to test the robustness of current theories in an empirically novel manner. We investigated function of female song in stripe-headed sparrows (Aimophila r. ruficauda), a Neotropical, duetting passerine, and found that during simulated territorial intrusions by a female, male or duetting pair, females: (i) sang more than males to same-sex and duet playback, (ii) played a leading singing role in all contexts, and (iii) showed a longer term song response than males. These results suggest that females sing competitively against other females, and that intrasexual selection may be greater among females than among males. This is the first songbird study to show a stronger vocal role in territory defence for females than males. Stripe-headed sparrows are group-living cooperative breeders, and preliminary data suggest that polyandry and/or resource defence may explain strong female singing behaviour. Stripe-headed sparrows may be a useful study species for expanding our knowledge of vocal communication in female animals.

Typical Males and Unconventional Females: Songs and Singing Behaviors of a Tropical, Duetting Oriole in the Breeding and Non-Breeding Season

“…Some species, including some monochromatic species, exhibit distinctive sex-specific songs or structural features (Mennill et al, 2005;Rogers, 2005;Logue et al, 2007). However, in other species, males and females have similar overall structure, but differ in a few, continuous parameters, such as frequency or number of syllables (Mennill et al, 2005;Brunton and Li, 2006;Illes and Yunes-Jimenez, 2009). Some of these species have fairly substantial differences in pitch or syllable number that even allows researchers to distinguish among males and females (Mennill et al, 2005).…”

“…Some of these species have fairly substantial differences in pitch or syllable number that even allows researchers to distinguish among males and females (Mennill et al, 2005). In still other species, males and females exhibit different levels of vocal complexity that may be indicative of selection for more elaborate songs in one sex over the other (Brunton and Li, 2006;Illes and Yunes-Jimenez, 2009). However, we suggest that troupials exhibit less sexually distinct songs than most previously examined species, supported by the substantial overlap of frequency and duration of their songs (Figure 3).…”

“…Comparing male and female song rates between the breeding and non-breeding seasons is valuable for determining the relative importance of male and female songs in regulating breeding vs. non-breeding activities (Tobias et al, 2012). Two studies report female song rates that exceed male song rates (Price et al, 2008;Illes and Yunes-Jimenez, 2009). However, no studies have examined how male and female song rates vary between the breeding and non-breeding season.…”

“…Most studies that have directly compared male and female songs have compared structural variation (Logue and Gammon, 2004;Mennill et al, 2005;Rogers, 2005;Brunton and Li, 2006;Hall, 2006;Molles et al, 2006;Dowling and Webster, 2013;Hahn et al, 2013;exceptions: Price et al, 2008;Topp and Mennill, 2008;Illes and Yunes-Jimenez, 2009). Comparing structure of male and female song has revealed interesting trends in the overall complexity or repertoire sizes of male vs. female song.…”

On the natural history of duetting in White-browed Coucals: sex- and body-size-dependent differences in a collective vocal display

“…It is these meta-parameters that determine the collective signal parameters and establish the particular style of a duet (Brumm and Slater 2007). Duet styles vary considerably between species, ranging from rather loose temporal associations such as in Stripe-headed Sparrows (Aimophila ruficauda), in which the female and male simply overlap their parts with no further coordination (Illes and Yunes-Jimenez 2009), to cases of a stimulus response type, where the phrase of one partner is answered by the phrase of the other [e.g. in the Whipbird Psophodes olivaceus (Rogers 2005)], to rapid antiphonal cycles where female and male fit their song elements precisely in the brief pauses between the elements of their partner [e.g.…”