December 21, 2012
Distinctive Male Peacock Love Call Allures Females From Afar
[Watch Video: Male Peacock Demonstrates 'Hoot-Dash Display']
redOrbit Staff & Wire Reports - Your Universe Online
The distinctive sound made by male peacocks just before mating attracts female voyeurs for reasons currently unknown, a Duke University researcher has discovered.
The India peafowl's unique pre-copulation ritual, which is also referred to as the "hoot-dash display," involves the male members of the Phasianinae family dashing toward a female companion and squawking once before beginning the act of mating.
Jessica Yorzinski, a biologist at the Durham, North Carolina university, first observed the unique behavior at Keoladeo National Park in northwestern India.
While the birds have "a number of different courtship calls [the hoot-dash display] is the only one specifically associated with the moment before copulation, a time when the female is finally right in front of the male," she said in a statement.
Considering how closely the call came to the act of copulation, the reasons for the ritual have puzzled experts. After all, he already has attracted a mate, and the copulation process is about to begin“¦ so why would the peacock feel compelled to call attention to itself, especially when it is about to be in a rather compromising position.
"In a sense, they're advertizing that they're distracted and vulnerable. It would be wise for a predator to capitalize on that," Yorzinski said. So out of curiosity, she recorded the call made during the hoot-dash display, and then used it in an experiment to see how female peafowl would react to the sound.
She alternately played the pre-mating noise one day, followed by a silent control on the following, and videotaped the reaction of the free-range females in the area. As it turns out, the hoot sounds attracted female peafowl, as they spend more time in the vicinity of loudspeakers on the days it played than on the alternate days.
"To make sure the birds weren't simply drawn to any noise, Yorzinski repeated a similar experiment with captive birds in an outdoor enclosure at Duke University. There, a speaker played two different sounds: peacock copulation calls, or crow caws," representatives from the National Evolutionary Synthesis Center (NESCent), an evolutionary research center supported by Duke University, explained.
"The results matched what she found in the wild," they added. "Captive females paid little attention to the speakers when crow caws were playing, but when the love whoops were played, the females moved toward the source of sound and spent more time near the speaker."
The reasons for the female´s behavior, and what they might learn from the males' call, remain unknown, Yorzinski said. It is possible that the noise advertises the fact that a peacock has found a mating partner in the hopes that he will attract additional potential mates.
"That dating boost could make up for the risks involved in disclosing his whereabouts to potential predators, especially in the birds' native habitat in South Asia where dense trees and grasses make strutting males hard for females to spot," NESCent officials said.
If that's the case, though, why don't peacocks replicate the call in other situations, making it appear as though they are more successful in the mating game than they really are in the hopes of attract willing females? Again, researchers currently do not know the answer.
"One of the biggest unanswered questions is why males don't fake it," Yorzinski said. "I've heard males making false calls when there's no mate in sight, so there definitely is some level of cheating going on. Figuring out why they don't do it more often would be the key."