Baby birds are sometimes known to shove their siblings out of the nest to gain their parents’ undivided attention, but barn owl chicks appear to be more altruistic. Scientists recorded the hissing calls of hungry and full barn owl nestlings (Tyto alba, pictured), then played the sounds back to single chicks settled in nests stocked with mice. The young owls that heard the squawks of their hungry kin delayed eating each rodent by an average of half an hour; those that heard cries indicating their invisible nest-mate was full ate the mice more quickly. The findings suggest that barn owl chicks give hungrier siblings a chance to eat first even when the nest is full of food, the researchers will report in an upcoming issue of Behavioral Ecology and Sociobiology. So is it true altruism? Maybe not. Nestlings may share food in exchange for help with grooming or to get the first crack at a later meal, the team says, suggesting a possible ulterior motive.
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