In a behavioral experiment, crows were able to learn to produce a set number of calls. This involves them planning in advance. From the sound of the first call in a numerical sequence, it is possible to predict how many calls the crows will make. A research team consisting of Dr. Diana A. Liao, Dr. Katharina F. Brecht and assistant professor Lena Veit led by Professor Andreas Nieder from the Institute of Neurobiology at the University of Tübingen has established this. Their study has been published in Science.
To be fair, I plan in advance not to make any calls because I don’t like talking on the phone anyway…