Figure 1.

Sequence of behaviours and vocalizations characterizing coalitionary aggression within a social group of unrelated, sexually immature female carrion crows. (a) The dominant individual C45 (left) recruits the second most dominant individual C59 (right). The recruitment is characterized by social bonding behaviour and a series of specific vocalizations between C45 (red) and C59 (yellow). (b) Initiated by a vocal signal of C45 the allies engage in a coordinated chase of the subordinate victim (C58, upper right). (c) Both aggressors immobilize the victim while pecking ferociously at its head. A fourth bird (C29, left) intervenes, presumably to the assistance of the victim, by pulling on one of the attackers’ wings. Acoustic time waves in panel a and b were created using the seawave package⁵⁰ in R⁵¹. Drawings courtesy of Kristina Fraune.