Young Eurasian Scops Owls make individually distinctive vocalizations

Abstract

AbstractVocal distinctiveness is expected to occur more often in colonial-breeding species as parents need to recognize their offspring in a large group of conspecifics. In this study, I examined the calls of the young of a territorial nocturnal raptor, the Scops Owl both before and after fledging. Contrary to what is expected for a territorial species, the calls of young owlets showed a high degree of repeatability in many acoustic features, particularly call duration, spectral centre of gravity, and spectral skewness. Discriminant analysis assigned 52.5% of the calls to the correct individual, and 77.5% when restricting analysis within broods. Inter-individual differences appear before fledging and were stable for multiple days. The results suggest that the vocalizations of young Scops Owls could potentially act as identity signals. However, the functional significance of acoustic signatures remains unclear; a few hypotheses are discussed. Acoustic distinctiveness could merely reflect the development of vocal individuality that is typical of the adults, with no net benefit to parents and offspring. However, it could also play a role in parent-offspring communication, preventing misdirected parental care to unrelated young, or helping the parents feed preferentially specific young, as was suggested earlier for this species. Acoustic signatures could also help brood mates maintain contact after fledging or mediate competition for food between them. Further studies are needed to determine whether parents and offspring do assess identity signals in vocalizations.