Challenges and new opportunities in deciphering the meaning of corvid call sequences.

Due to their complex social systems and remarkable cognitive abilities, corvids are interesting candidates for large scale comparative research on the meaning of animal calls. However, research on corvid communication has primarily focused on individual signatures or mimicry capabilities, and investigations into the meaning of their calls have yielded comparatively fewer results. This discrepancy can be attributed to several challenges faced by researchers, including difficulties in identifying the units that convey meaning, accurately determining the specific context associated with a call, and the limitations of traditional playback methods when applied to species with extensive repertoires and considerable flexibility in call sequences. In this review, we outline a series of emerging research avenues—recently explored in other songbirds and mammals—that may prove valuable for researchers seeking to understand the meaning behind corvid call sequences. We specifically address the various approaches to identify meaning-bearing units; the strategies for refining the definition of ‘context’ in the assessment of corvids’ repertoires; and the novel protocols and methods that offer alternative perspectives on meaning, beyond the classical playback experimental approaches that were historically used to assess the meaning of calls or call sequences.