Male common loons, Gavia immer, produce a territorial vocalization called the yodel. We quantitatively examined yodels using discriminant and cross correlation analysis. Both techniques correctly assigned the majority of the male's yodels to the proper group, however discriminant analysis was more accurate for making long term comparisons of a yodel's stability. Of four male loons in a color marked, breeding population at the Seney National Wildlife Refuge in Michigan, each male's yodel was different and these differences were maintained over the six years of this study. There is a suggestion that changes in the yodel may be related to territory and mate switching, indicating that individuality in the yodel may be linked to female choice.
common loon, yodel, vocal-tagging