Testosterone-Induced Incubation Patches of Phalarope Birds.

In order to determine the endocrine factors in the production of the incubation patch of phalarope birds (Steganopus tricolor and Lobipes lobatus), adults of both sexes have been maintained in captivity and injected with estradiol, testosterone, or prolactin, or with different combinations of these hormones. Only testosterone and prolactin in combination produced incubation patches in all birds, both male and female, in the two species.