Not Such a Drag: Peacock's Train Doesn't Affect Its Flight

A new study shows that the vibrant plumage of peacock doesn't affect the bird's flight.

Peacock's spectacular train is one the most striking examples of sexual selection in the animal kingdom, the researchers said. The outrageous train of feathers accounts for as much as 60 percent of the bird's total body length. Male peacocks use these extravagant trains to court female peacocks. Biologists earlier believed that the pompous show of attraction hurt the bird's flying abilities.

The study was conducted by University of Leeds researcher Dr Graham Askew.

"These feathers weigh about 300g and can exceed 1.5m, so it's expected that the male birds would be making a significant sacrifice in their flight performance for being attractive-possibly giving up their lives if the train restricts escape from predators such as tigers and leopards in their natural environment," Dr Askew, from University's School of Biomedical Sciences, said in a news release.

For the study, the researchers filmed five Indian peacocks taking off using two high-speed cameras. The researchers wanted to know how the train affects the bird's flight.

Peacocks lose their feathers at the end of the breeding season. The team trimmed the plumage to test the bird's flying abilities without the train.

To their surprise, the team found that the feathers don't interfere with peacock's flying abilities. Rather, the birds would have had the same technique to take off if they didn't have the magnificent train behind them. The team looked at the position of each bird's centre of mass, their wing motions and the movement of the train during the take-off.

The train's drag was tested in a wind tunnel. The team mounted a detached train in a wind tunnel to assess if the feathers slow down the bird. The researchers found that the drag did double; however, the birds had to use just a tiny amount of power to overcome this drag.

"Intuitively you expect that the train would detrimentally affect flight performance and so not finding a detectable effect was a bit surprising," Dr Askew said in a news release. "These birds do not seem to be making quite the sacrifices to look attractive we thought they were."

The study is published in the Journal of Experimental Biology.