by Cassandra Hockman
Ben Vernasco knew he wanted to pursue a Ph.D. in conservation biology while studying tropical birds in Peru. After his trip, he got in touch with his mentor, Brandt Ryder, a research ecologist at the Smithsonian Migratory Bird Center at the Smithsonian National Zoological Park in Washington, D.C.
Ryder and his Virginia Tech colleague Ignacio Moore, an associate professor of biological sciences in the College of Science, had just received a National Science Foundation grant with a spot for a graduate student. Vernasco was in luck.
Now, Vernasco is a doctoral student in biological sciences at Virginia Tech, and studies the wire-tailed manakin, or Pipra filicauda – a tropical bird named for the wired filaments on its tail and known by researchers for its unique social display: the males perform to attract the females.
To some researchers, this display looks like a dance – these birds perform with quick, smooth moves, back and forth on a branch, while flicking their wings to make sound. Some people have likened the movements of the red-capped manakin to Michael Jackson’s moonwalk: a seamless backward slide. And another species, the club-winged manakin, rubs its wings together over its back to make a buzzing noise, a movement so fast it is invisible to the naked eye.
As part of their display, manakins perform on the same designated perches within their territories. They even alter the habitat around their perch by tearing down leaves to make it a better arena to dance in, said Vernasco.
But dancing to attract females is not the only thing unique about these displays – males also display with other males. Within a particular territory, males will display together in order to form the basis of what Vernasco explained are social coalitions. Within these coalitions, the same males display together for years in order to develop social hierarchies.
Watch the elaborate dance of the wire-tailed manakin:
During these male-to-male displays, one male will assume the position of the female, and the other will display to its comrade as if it were displaying to a female. Then, when a female comes by, the territory-holding male will take over and perform in order to mate, whereas the non-territory holders, or ‘floater’ males, will step aside until he makes his way up the social ladder.
“The more social bonds these floaters have,” said Vernasco, “the more likely they are to eventually gain a territory themselves and sire offspring.”
With Ryder and Moore’s guidance, Vernasco investigates this elaborate social behavior and its underlying physiology to get a better sense of the birds’ reproductive success and overall health. This includes measuring testosterone levels, which have been shown to increase when the males gain territory.
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Header photo: Wire-tailed Manakin by Joao Quental via Wikimedia Commons