Visual cues and parental favouritism in a nocturnal bird.
Visual signals are crucial for parent-offspring communication, although their functioning has been neglected for nocturnal birds. Here, we investigated parental preference for nestling coloration in nocturnal conditions--a question hitherto unexplored--in a nocturnal raptor, the scops owl (Otus scops). We assessed how parents allocated food during the night in relation to a manipulation of ultraviolet (UV) reflectance of the cere (skin above the beak) of their offspring. Reflectance of the cere shows a marked peak in the UV part of the spectrum, and location of the UV peak is related to nestling body mass (i.e. heavier nestlings have a UV peak at lower wavelengths). We found evidence of parental bias in favour of lighter offspring: UV-reduced nestlings gained more weight during the night than their control siblings. This study provides the first experimental evidence of the use of visual cues for parent-offspring communication in a nocturnal bird.
Parejo
Deseada
D
Departamento de Ecología Funcional y Evolutiva, Estación Experimental de Zonas Aridas (C.S.I.C.), General Segura 1, E-04001 Almería, Spain. parejo@eeza.csic.es
Avilés
Jesús M
JM
Rodríguez
Juan
J
D000818:Animals; D049628:Body Size; D003463:Cues; D016014:Linear Models; D009425:Nesting Behavior / Q000502:physiology*; D010364:Pattern Recognition, Visual / Q000502:physiology* / Q000528:radiation effects; D013030:Spain; D020305:Strigiformes / Q000502:physiology*; D014466:Ultraviolet Rays