This study examines the effects of experimental manipulation of brood size (one or two squabs) on the behavior, interclutch interval, plasma LH concentrations, and weights of ring dove parents. Twelve dove pairs were observed, sampled, and weighed over a cycle with one and a cycle with two squabs. Before hatch, no parameter showed any difference between pairs which would subsequently have one or have two squabs. After hatch, males and females having one squab fed less, while males showed more perch-, bow-, and nest-cooing over the 2 weeks after hatch. Females also showed more nest-cooing with one squab and a shorter interclutch interval. For both sexes the plasma LH concentrations were higher when rearing a single squab, showed a lesser decrease after hatch, and increased more rapidly. Both sexes also showed a smaller weight loss when rearing a single squab. The results show that the intricate relationships between behavior, physiology, and reproduction in the ring dove are tuned to brood size and emphasize the latter factor as an important and meaningful variable in the doves' reproductive cycle.