Developmental curve of play in wild goshawks (Astur gentilis)

Abstract

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  We provide the first systematic observations of object play in young goshawks.
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  Play followed a distinct rise–peak–decline developmental pattern.
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  Object play began around 45 days of age, peaked at 55–70 days, then declined.
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  This is the first documented ontogenetic window of play in a bird of prey.

Play behaviour has been documented in diverse animal taxa. In some well-studied species, it has been found to follow a characteristic developmental curve, with a distinct onset, peak and decline. However, studies of the ontogeny of play in birds of prey are lacking due to observational challenges. Here, we present the first systematic study of object play in wild northern goshawks, Astur gentilis. We documented 39 play events across seven territories. Play behaviour was absent during the nestling period, and first observed at approximately 45 days of age, shortly after fledging. There was a pronounced peak during 55–70 days of age, followed by a decline. Observed behaviours included repeated attacks on stationary objects, object tossing, chasing and recapture. Behaviours were directed towards branches, pine cones, a dead mouse and anthropogenic objects. These behaviours fulfilled established criteria for play, differing from functional hunting or feeding behaviour and occurring in relaxed contexts without immediate reward. We provide the first systematic evidence for object play in goshawks and show that a structured developmental window of object play is present in an accipitriform bird of prey. The timing of peak play coincided with increasing independence and the refinement of motor coordination and hunting skills. This may suggest a functional role of play in skill acquisition, or that play behaviour emerges as a by-product of increased motivation to exhibit hunting behaviour. These findings expand the taxonomic scope of systematic play research and contribute to understanding the developmental organization of behaviour in birds of prey.

Play behaviour has been documented in diverse animal taxa. In some well-studied species, it has been found to follow a characteristic developmental curve, with a distinct onset, peak and decline. However, studies of the ontogeny of play in birds of prey are lacking due to observational challenges. Here, we present the first systematic study of object play in wild northern goshawks, Astur gentilis. We documented 39 play events across seven territories. Play behaviour was absent during the nestling period, and first observed at approximately 45 days of age, shortly after fledging. There was a pronounced peak during 55–70 days of age, followed by a decline. Observed behaviours included repeated attacks on stationary objects, object tossing, chasing and recapture. Behaviours were directed towards branches, pine cones, a dead mouse and anthropogenic objects. These behaviours fulfilled established criteria for play, differing from functional hunting or feeding behaviour and occurring in relaxed contexts without immediate reward. We provide the first systematic evidence for object play in goshawks and show that a structured developmental window of object play is present in an accipitriform bird of prey. The timing of peak play coincided with increasing independence and the refinement of motor coordination and hunting skills. This may suggest a functional role of play in skill acquisition, or that play behaviour emerges as a by-product of increased motivation to exhibit hunting behaviour. These findings expand the taxonomic scope of systematic play research and contribute to understanding the developmental organization of behaviour in birds of prey.