{"fact":"Not only can crows control *if* they vocalize, they also seem to control *what* they vocalize, changing their calls depending on the situation.","context":"This finding suggests that crows do not use stereotyped vocalizations during the cued task but rather learn to adjust the acoustic output as needed.","source":"Katharina F. Brecht; Steffen R. Hage; Natalja Gavrilov; Andreas Nieder, Volitional control of vocalizations in corvid songbirds, 10.1371/journal.pbio.3000375","index":208}