Abstract
Blood samples collected from free-living Wilson's phalaropes during the reproductive season were analyzed for testosterone, dihydrotestosterone, estradiol-17β, and progesterone. Levels of testosterone were seven times greater in nonincubating males than in females. During incubation males underwent a reduction in testosterone and dihydrotestosterone to levels similar to those of females. Estradiol-17β values were higher in females than in incubating males and comparable to values reported for other avian species. Progesterone was significantly greater in females than in incubating or nonincubating males. Maximum levels of progesterone were detected in laying females. Progesterone levels increased in males during incubation while testosterone and dihydrotestosterone levels decreased. These results indicate that the greater intensity of competition for mates among females and exclusive male parental care characteristic of this species is not based upon a reversal of the typical avian levels of androgens and estrogens in males and females.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
