Previous experience with the activities of courtship plus nestbuilding appears to be the source of the difference
between experienced and naive doves' progesterone-induced incubation. Experience with additional phases of
the breeding cycle reduces the latency for nest orientation without necessarily increasing the probability of the
establishment of incubation within the 24-hr test period. These results are concordant with Lehrman's (1958)
observation that the onset of incubation during a breeding cycle is facilitated when pairs of reproductively
experienced doves can engage in both courtship and nestbuilding activity for some 7 days. The present study
indicates that previous courtship and nestbuilding activity also facilitates progesterone-induced incubation