The effect of the magnitude of sexual reinforcement on the extinction of a running response was studied in quail. In Experiment 1, a group of subjects (L) received copulatory access to eight females, whereas a second group (S) received access to a single female. Both groups acquired the running response. During extinction, Group S showed a fast decrease in responding, whereas Group L persisted longer. In Experiment 2, males were allowed a choice between one or eight females. Preference for eight females demonstrated that males discriminated between the two reward magnitudes and that access to eight females had a larger reinforcing value than access to one female. The results are discussed within the context of the paradoxical reinforcement effects and the divergence in learning mechanisms in birds.