Transmission among birds Ok, a rather standard photo of a bird of prey in flight. My excuse is that the bird was looking at me and so on the pic it seems to be looking at you. It is a juvenile marsh harrier (Circus aeruginosus, “busard des roseaux” in French). The plumage is almost entirely chocolate-brown and the top of the head and throat have a lighter yellowish color. Juveniles differ from females by their brown, not pale, shoulders. Remember this cute little bank vole shown in my second-last pic? Marsh harrier is one of its predators. Do such predators learn to hunt on their own? A Polish ornithologist, Ignacy Kitowski, investigated this question some years ago. During summer, after breeding, marsh harriers practice communal roosting and spend night together in reedbeds. Ignacy observed them hunting alone or in small groups. He found that the number of dives (attempts to catch a prey) were more numerous when birds were hunting together. Adults were more successful than juveniles, but juveniles improved their chances when hunting with adults (50% versus 10% success rate). Scientists distinguish between vertical (adult to juvenile) and horizontal (juvenile to juvenile) transmission. For instance, at school, do our kids learn both from their professors (vertical transmission) and from their school mates (horizontal transmission)?! To date, strong evidence of social learning exists in birds for foraging, predator recognition, song, and mate choice. Social influence occurs when the presence of other members of the same species (1) causes the observing animal to direct its attention to a place or object (local or stimulus enhancement, (2) affects the motivation of the observing animal, or (3) results in a reflexive response. For our juvenile marsh harriers, only lower level learning mechanisms (1 and 2) seem to be involved. No need for complex learning strategies when simple ones are effective. Finally, note that for captive-breeding and release programs to be successful, birds might have to be taught some critical skills (ex. their migration route or how to recognize their predators) before being released.