Date of Award


Publication Type

Master Thesis

Degree Name



Biological Sciences

First Advisor

Stéphanie Doucet


Biological sciences



Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.


Traditional studies of sexual selection have focused on elaborate male traits and female preferences. In many species, however, females exhibit some degree of ornamentation, and this pattern warrants examination. I investigated whether plumage colouration honestly signals quality and reproductive success in mutually ornamented royal flycatchers (Onychorhynchus coronatus ), and to determine whether or not they exhibit mutual mate preferences by ornamentation. In Costa Rica, I monitored birds throughout the breeding season and collected data from breeding pairs. In the lab, I performed reflectance spectrometry on feathers and quantified aspects of quality. I found that both male and female plumage colouration honestly revealed aspects of quality and predicted reproductive success. However, I found no evidence that royal flycatchers mate assortatively. I conclude that plumage colouration may be an honest, sexually-selected trait in both sexes, but that assortative mating does not explain the evolution of female ornamentation in this species.