When, what, and whom to watch? Quantifying attention in ravens (Corvus corax) and jackdaws (Corvus monedula).
Résumé
Complex social life requires monitoring of conspecifics. The amount and focus of attention toward others has been suggested to depend on the social relationships between individuals. Yet there are surprisingly few experiments that have tested these assumptions. This study compared attention patterns toward conspecifics in two corvid species, ravens (Corvus corax) and jackdaws (Corvus monedula). Birds were confronted with affiliated and non-affiliated conspecifics engaged in foraging and object manipulation. Visual access to the model bird was provided through two observation holes, which allowed measurement of exactly how often and for how long observers watched the other. Overall, ravens were more attentive to conspecifics than were jackdaws. Moreover, only ravens showed higher interest toward food-related than object-related behaviors of the model and toward close affiliates than non-affiliates by increasing the duration rather than the frequency of looks. These results are in accordance with predictions derived from the species' foraging biology and suggest that the facultative social, but highly manipulative, ravens use and value information from others differently than do the obligate social jackdaws.