Is Morphometry an Indicator of the Number of Sexy Syllables in the Song of Yellow-Fronted Canary (Serinus mozambicus)?

Abstract

Birds use song for several goals as defending territory, alerting a partner to the presence of a predator, or wooing a female for breeding. This study aims to identify the morphometric parameters which determine the variability of the number of syllables in the “sexy” songs of yellow-fronted canary. For this purpose, sixteen morphometric parameters were measured among 170 yellow-fronted canaries captured, in four agroecological zones in North Benin. The results showed that the morphometry of yellow-fronted canary varies according to its habitat and the type of song. The categorization of the sample studied allowed to retain two groups which differ in the importance of body characters and the number of sexy syllables issued when singing. Yellow-fronted canaries from the Sudanese climate zone not only have superior morphometric characters compared to other zones, but also have a song composed of several different sexy syllables. A binary logistic regression model with selection of variables revealed that the index of beak shape, abdomen length, and tail length are the determining characteristics of the number of sexy syllables. These results are needed for future breeding and conservation studies of the species.