Relative pitch perception in the European starling (Sturnus vulgaris): further evidence for an elusive phenomenon.

Relative pitch perception in animals has been difficult to demonstrate. This failing is due in part to stimulus sets that make an absolute pitch solution viable. In Experiment 1, starlings failed to acquire a discrimination that could be solved only on the basis of relative pitch. In Experiment 2, starlings were trained on a smaller set of pitch patterns, for which both absolute and relative pitch solutions were available, then tested with three series of unreinforced probe stimuli. Series 1 assessed stimulus control by absolute pitch. In Series 2, absolute pitch cues dictated one response, and relative pitch cues dictated a different response. Results indicate that starlings extract relative pitch from artificial pitch patterns only after acquiring a discrimination that permits both absolute and relative pitch solutions. Results are discussed in terms of the relative salience of absolute and relative pitch.