Conspecific challenges provoke female canyon wrens to sing but not to duet
Song by female birds is rare in some species, particularly at north-temperate latitudes. Nevertheless, female song can carry important signal content and may be used in functional ways, both when sung solo and when combined into partner duets. Evidence supports the idea that duets reflect elevated threat levels because they indicate partner cooperation, but this comes from species with frequent female song and duetting. Here we asked the following questions about infrequently given female song in canyon wrens (Catherpes mexicanus) in Western North America. Do female birds use song in a context that implies functional significance? Do canyon wren mates combine their songs to form duets? Are duets a more threatening signal than non-overlapping dual-sex solo songs? To address these questions, we challenged canyon wrens with paired simulated intruders singing alternating solo songs or duets formed by overlapping male and female songs with consistent timing. Results indicated that female canyon wrens approached and sang in response to conspecific song playback as quickly as males did and increased their song rates significantly. Partners did not overlap their songs to create duets more often than expected by chance, and neither sex responded more strongly to duets than to solo songs. Outcomes match the prediction that duets only carry different signal content from solo song in species that frequently duet, and suggest that canyon wren female song is highly functional despite being rarely used outside of contest situations.
Animal signals mediate social interactions in myriad ways. The majority of studies of avian song have focused on conspicuous, frequently given, signals but infrequently given signals may also have important fitness consequences. We examined how the usage of a rare signal, canyon wren female song, changed during contest situations and in response to a coordinated duet versus non-coordinated solo songs. Rates of female song increased significantly during contest situations, but duets did not provoke stronger responses than solos. Although duets are threatening to species that duet (including many wren species), they do not appear to be universally salient. Canyon wren female song, in contrast, carries strong signal content despite being used infrequently outside of contest situations. Results highlight the potential functionality of rare signals, as well as the variability in signaling strategies across avian species.
KeywordsBird song Vocal duets Female song Rare signals Canyon wren Catherpes mexicanus
The following agencies provided access to field sites: The U.S. Forest Service, CO Parks and Wildlife, Larimer Co., Boulder Co. OSMP, Denver Mountain Parks, and Fort Collins Natural Areas. We thank Andrew Spencer for allowing us the use of audio files. Henrik Brumm and two anonymous reviewers provided comments that improved the manuscript.
This work was supported by a grant from the University of Northern Colorado’s Provost Fund.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
All applicable international, national, and/or institutional guidelines for the care and use of animals were followed. All procedures performed in studies involving animals were in accordance with the ethical standards of the University of Northern Colorado’s Institutional Animal Care and Use Committee (Protocol No. 1506C-LB-Birds-18).
- Bradbury JW, Vehrencamp SL (2011) Principles of animal communication, 2nd edn. Sinauer, SunderlandGoogle Scholar
- Catchpole CK (1977) Aggressive responses of male sedge warblers (Acrocephalus schoenobaenus) to playback of species song and sympatric species song, before and after pairing. Anim Behav 25:489–496Google Scholar
- Fair J, Paul E, Jones J (eds) (2010) Guidelines to the use of wild birds in research, 3rd edn. Ornithological Council, Washington DCGoogle Scholar
- Hall ML, Rittenbach MRD, Vehrencamp SL (2015) Female song and vocal interactions with males in a neotropical wren. Front Ecol Evol 3:12Google Scholar
- Logue DM (2005) Cooperative defence in duet singing birds. Cogn Brain Behav 9:497–510Google Scholar
- Najar N, Benedict L (2016) Female song in new world wood-warblers (Parulidae). Front Ecol Evol 3:139Google Scholar
- Nice M (1943) Studies in the life history of the song sparrow. II. Trans Linn Soc NY 6:l–328Google Scholar
- Shuler JB (1965) Duet singing in the Carolina wren. Wilson Bull 77:405–405Google Scholar
- Spencer A (2012) Female song in canyon wrens, with notes on vocal repertoire. Colorado Birds 46:268–276Google Scholar