Effects of paternal deprivation on beak coloration

Abstract

For ornamented species, beak coloration is a key factor that is considered by the female. In zebra finches (Taeniopygia guttata), females prefer males that exhibit redder beaks in comparison to those that exhibit more orange beaks. This carotenoid coloration signals bird health, with many factors influencing adult beak color development, including stress and immune challenges during early life. Like many bird species, zebra finches are biparental. However, few studies have tested how paternal removal affects offspring development. We tested how paternal removal affected beak coloration of sons. We set up two treatment groups: one group that had the father removed from the nest at hatching (early removal) and another that had the father removed at fledging (late removal), as well as a control group with no paternal removal. Once adults, we measured the brightness, hue, and saturation of the upper mandible of male offspring using a spectrophotometer. Birds in the late removal group had breaks with significantly lower red reflectance in comparison to the control group. These results suggest that paternal removal during fledging disrupts the proper development of beak coloration.