Skip to content

Dunnocks Showed No Tendency to Breed With Similar-sized or Similar-condition Birds

Dunnock perched among bramble vegetation
Research · Behaviour

A New Zealand preprint posted on 25 August 2026 examined sexual selection in dunnocks (Prunella modularis) across multiple breeding seasons. The researchers tested for assortative mating—that is, whether breeding partners tended to resemble each other in body size or condition. They also asked whether sexual selection differed between males and females and whether the adult sex ratio affected its strength.

Across seasons, the study found no evidence that similar-sized or similar-condition birds were more likely to breed together. Larger or higher-condition individuals also showed little evidence of producing more offspring. The authors argue that this fits the absence of a strong mating pattern based on these traits.

Males experienced somewhat stronger sexual selection than females, although the difference was small to moderate. Selection also became stronger in both sexes when the adult sex ratio was more male-biased. The authors suggest two non-exclusive explanations: some females may be more successful than others at obtaining multiple mates even when males are abundant, and males may become more willing to share breeding with other males when there are more males in the population.

The study is currently a preprint and has not yet been peer reviewed.

Sources and image credit

  1. Cerqueira, G. S., Santos, E. S. A., Holtmann, B., Lara, C. E., Nakagawa, S., & Macedo-Rego, R. C. (2026, August 25). The intensity of sexual selection and the absence of assortative mating patterns in Prunella modularis (Aves: Passeriformes) [Preprint]. EcoEvoRxiv. https://doi.org/10.32942/X2BQ2QPrimary preprint. Multiple breeding seasons were analysed for assortative mating, sex differences in sexual selection and effects of adult sex ratio. The authors found no evidence of size- or condition-assortative mating, somewhat stronger sexual selection in males, and stronger selection in both sexes when the sex ratio was more male-biased. The preprint has not been peer reviewed.

Image: Charles J. Sharp — Dunnock (Prunella modularis) at College Lake, Buckinghamshire, United Kingdom, photographed 24 April 2021; Wikimedia Commons. Representative species image, not one of the study birds. CC BY-SA 4.0. · CC BY-SA 4.0 · Source

About this content: This story was produced with AI assistance within an editorial workflow developed by Wildlife Vagabond. Editorial responsibility remains with Wildlife Vagabond.How AI is used

Behaviour

SPECIES IN THIS STORY

Species in this story

Dunnock Prunella modularis Explore species

Independent research and conservation news archive

Did you find this information useful?

Wildlife Vagabond is independently built and maintained. Voluntary support helps cover source verification, hosting and continued work on research and conservation news.

Support Wildlife Vagabond

The news archive will remain freely available.