Abstract
Ninety-six pairs of ring doves with previous breeding experience were treated with estrogen, progesterone, or left untreated. They were then placed in pairs in cages containing nests and eggs and observed until they began to sit on the eggs. Untreated birds sat after 4-10 days, progesterone treated sat immediately, and estrogen treated sat after 1-3 days. There was no evidence that the hormones affected prolactin. The results of incubating and mating behavior suggest that stimuli provided by the bird s activity affect the hormone secretion. 17 refs.