Sept. 1 (UPI) -- Research by the Smithsonian Tropical Research Institute shows the male golden-collared manakin cleans his display area before performing to attract females.
The golden-collared manakin, or Manacus vitellinus, is a bird found in tropical regions such as Panama. The males have a bright-yellow throat and beard to attract females.
The study of juvenile male golden-collared manakins who received extra testosterone, published this week in Animal Behavior, were stimulated to clean up their display area before performing for females.
Scientists found that the cleanliness was influenced but not determined exclusively by hormone levels.
"Testosterone-treated young males really got into cleaning up the display court," Ioana Chiver, a post-doctoral fellow at STRI, said in a press release. "They removed significantly more leaves than untreated males and even pulled up small tree seedlings. Adult males come up with original ways to remove the leaves from the display area. We think of younger animals as being more innovative, but here we see that hormones may be playing a role in motivating the birds to persistently seek new ways to court their mates."
Adult male golden-collared manakins strut in groups called leks in a defined display area on the forest floor that they meticulously clean by removing dead leaves and foliage that might obstruct a female's view.
The males perform complex acrobatic moves, leaping from one tree to another all while making snapping sounds by beating their wings above their heads to attract a female's attention.
"Even when treated with testosterone, females were not motivated to clean the male's display area, although they did become more aggressive and show some other male display behaviors," Barney Schlinger, professor at UCLA, said. "That tells us that hormones alone are not enough: testosterone is activating specific neural circuits in males. Females either do not have these circuits, or they are insensitive to testosterone."
Scientists even added weights to the undersides of leaves in the display area to make them heavier to see how far the males would go to clean their display area.
"Testosterone-treated young males really got into cleaning up the display court. They removed significantly more leaves than untreated males and even pulled up small tree seedlings," Chiver said.