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Bird song has historically been characterized as a primarily male behavior that evolves through sexual selection pressures involved in mate attraction. More recently, researchers showed that female song is far more prevalent in songbirds than previously thought, raising new questions about how other social functions of birdsong and sexual selection pressures on females might affect song evolution. Certain breeding systems, particularly cooperative breeding, are hypothesized to change social dynamics and sexual selection pressures on males and females and may thus influence song evolution in both. Here, we construct a large-scale database synthesizing species-level information on the presence of female song, the characteristics of presumably male song, social variables, and breeding systems, and we perform comparative phylogenetic analyses. Our results suggest that cooperative breeding and female song co-occur significantly more than expected and exhibit co-evolutionary dynamics; in particular, cooperative breeding appears to decrease the likelihood that female song is lost. Notably, we find evidence that these trends might be linked to certain social features associated with cooperative breeding, including social bond stability, but not others, such as increased group size. In addition, we observe that song repertoire size appears to evolve more slowly in cooperative breeding lineages. Overall, our findings demonstrate that cooperative breeding may have complex and sex-specific effects on song evolution, maintaining female song while slowing the rate of male song elaboration, suggesting that song in cooperatively breeding species could function in ways that differ from the traditional mate-attraction paradigm and that lesser-studied functions of songs may be evolutionarily consequential.
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This content will become publicly available on April 15, 2026
Accurate prediction of olive‐sided flycatcher breeding status using song rate measured with autonomous recording units
Abstract Autonomous recording units (ARUs) are recognized for their use in detecting vocalizing bird species to assess presence, occupancy, and density, but their potential to monitor reproductive status of individuals and reproductive rates is not well known. We investigated whether song rates derived from ARU data, when combined with the known date, can be used to predict the proportion of male songbirds in 3 breeding status classes (single, paired, and feeding young). We monitored breeding status with weekly field visits and collected daily ARU recordings at 46 olive‐sided flycatcher (Contopus cooperi) breeding territories in northwestern Canada in 2016–2017. We tested 4 variations of a hierarchical multinomial regression model that used time of day, day of year, and song rate derived from 2‐minute recordings to predict breeding status, and evaluated models using a novel, likelihood‐based approach. We found the top model correctly estimated 79% of the observed proportions of birds in each breeding status across the length of the breeding season. Although date was the primary predictor of breeding status, singing rate reduced some of the uncertainty and provided more accurate estimates for a given time. A major challenge to prediction accuracy and data interpretation was accounting for bird movement and the associated impact on detection, which we partly addressed by limiting our study to individuals who were detected on at least 30% of ARU sampling days. We demonstrate that ARUs can be used to assess breeding status in a cryptic, low‐density species at risk such as the olive‐sided flycatcher, suggesting this method could be applied to a wider range of species to better understand demographics and population dynamics, and inform management decisions, for bird species of concern.
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- Award ID(s):
- 2136198
- PAR ID:
- 10595490
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- The Journal of Wildlife Management
- ISSN:
- 0022-541X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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