Table I shows that a greater number of pairs with nestbuilding experience (group III) established incubation
within 1 hr after introduction than group I naive pairs (Fisher-Yates test, P 0.025 one-tailed) and group II pairs
(P = 0.005). Tests of the other relevant differences in the 1-hr period were not significant. Although all groups
showed increases in total number of pairs exhibiting incubation after 24 hr, the differences among the groups
were unchanged. Again, significantly more group III pairs exhibited incubation than did group II pairs (P =
0.05). Interestingly, the incubation response of group II pairs at the 24-hr test isequivalent to the incubation level exhibited by group III pairs during the 1-hr test