Head ornaments in owls: what are their functions

摘要

We studied head ornamentation in owls by focussing on the hypothesis that it may serve both intra- and interspecific communication. We carried out pairwise comparisons of morphological, ecological and behavioural traits on a subset of closely related species with contrasting head ornamentation patterns. We found that the degree of head ornamentation was associated with habitat and activity rhythm, highly ornamented species (e.g., most of the genus Bubo) living preferentially in open habitats and being active by day, but not with body size. Although our results do not exclude the possibility that head ornaments may represent a warning mechanism to startle predators and mobbers, they nevertheless suggest that such signals have evolved for visual communication with conspecifics, being more expressed in species that may use them more effectively without incurring the risk of predation or disturbance.