Kushini Kalupahana ‘The mimic and the fool: A tiny bird’s use of vocal mimicry as an antipredation strategy’

Vocal mimicry occurs in nearly 20% of songbird species, yet the constraints on mimetic accuracy and its consequences for function remain poorly understood, particularly in alarm calling and predator deterrence contexts.

Abstract

Kushini’s research focuses on the brown thornbill (Acanthiza pusilla), a native Australian songbird that mimics the alarm calls of several other bird species to deter nest predators such as pied currawongs (Strepera graculina), deceiving them into thinking that an aerial threat, such as a hawk, is nearby. She investigated how physical constraints affect mimetic capabilities in these tiny birds by examining how differences in body size between thornbills and the species they mimic, and among thornbills themselves, relate to mimetic precision through comparative trait analyses. To examine how variations in mimetic accuracy influences predator responses, she conducted playback experiments on pied currawongs using mimetic alarm calls of differing accuracy, recorded from brown thornbills at the same study site, and quantified their vigilance responses and feeding behaviour. Together, these approaches ask whether a mimic needs to be perfectly accurate for its alarm calls to work, and how receivers balance the costs of responding to a false alarm against the costs of ignoring a genuine one. She expects this work will advance our understanding of how vocal mimicry is maintained across a broad range of acoustic accuracy, with broader implications for predator-prey interactions and adaptive survival strategies in small birds.

Biography

Kushini Kalupahana is a third-year PhD candidate at the Research School of Biology, Australian National University. Her research investigates vocal mimicry and its functions in the brown thornbill, a native Australian songbird. She conducts her fieldwork at the Australian National Botanic Gardens, home to a population of about 150 brown thornbills, most of which are banded as part of this study. She monitors these birds, records their mimicry, and conducts playback experiments with pied currawongs, one of the main nest predators of this thornbill population.

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