Zebra Finches Decode Calls by Meaning

Zebra finches can not only distinguish the full range of their species' vocalizations but also organize them by meaning, according to a new study. The results suggest a surprising level of semantic understanding in the birds. Many social animals use a rich repertoire of vocalizations to communicate their needs, emotions, and awareness of the environment. Researchers have long tried to decode these sounds – essentially the species' "language" – by grouping them into call types based on how they sound, the situations in which they are used, and how other animals respond. However, it is unclear whether these categories reflect the animals' own perception or understanding of meaning. Zebra finches, highly social songbirds that use around 11 distinct call types for diverse social behaviors, offer a useful model to evaluate these questions. To test how adult zebra finches classify their species' vocalizations, Julie Elie and colleagues performed an experiment involving 12 finches, in which the birds had to distinguish one rewarded call type from the other ten nonrewarded call types, including those from other, unfamiliar species. Elie et al. found that these birds have a remarkable ability to distinguish all call types in their vocal repertoire, demonstrating that they can accurately perceive and categorize their species' vocal signals. Importantly, the authors found that call "misclassifications" were more common between call-types used in similar behavioral or social contexts, suggesting that zebra finches organize calls semantically and form mental representations of their underlying meanings.