Peacock's train is not such a drag

September 17, 2014
A Peafowl flaring his feathers. Credit: Wikipedia.

The magnificent plumage of the peacock may not be quite the sacrifice to love that it appears to be, University of Leeds researchers have discovered.

Dr Graham Askew, from the University's School of Biomedical Sciences, filmed five Indian peacocks taking off using two high-speed video cameras to try to work out what price male birds pay for carrying the spectacular iridescent feathers they use in displays to attract females.

"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 said.

He filmed the take-offs of birds carrying full plumage in 3D, and then filmed the same birds taking off without their trains. The display feathers, which naturally moult at the end of the breeding season, were cropped to judge the change in take-off performance between the two states.

To his surprise, Dr Askew found there was no significant difference.

Dr Askew observed the position of each bird's centre of mass, their wing motions and the movement of the train in take-off and then calculated the amount of power used by the birds to accelerate and gain height over the first two wing beats. He found it was essentially the same, regardless of the presence or absence of the train.

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

He added: "The train of the peacock is one of the most iconic examples of in the animal kingdom. It has been thought that such elaborate ornamentation carries a functional cost for the bearer. These results therefore have broader ramifications for evolutionary biology's understanding of sexual selection."

Dr Askew also looked at how much drag the train created during take-off by mounting a detached train in a wind tunnel. Although the drag doubled, overcoming that drag is only a tiny part of the power used by the birds during take-off. Therefore, the impact of the train on the overall take-off performance is negligible, allowing birds with and without trains to invest the same amount of power in the ascent.

The results do not mean that having an ornate train carries no costs for peacocks. Dr Askew pointed out that the feathers might adversely affect flight stability and the ' ability to run. Just creating the ornate plumage is a costly exercise; invest about 3% of their daily metabolic energy budget in train growth.

Explore further: Genome study indicates peacock eyespots likely developed to impress females

More information: Graham N. Askew, 'The elaborate plumage in peacocks is not such a drag,' will be published in The Journal of Experimental Biology on September 18 2014 DOI: 10.1242/jeb.107474

Related Stories

Rules of attraction: Catching a peahen's eye

July 24, 2013

Getting the undivided attention of a female is tough at the best of times but it's even harder when surrounded by other male suitors. It's no wonder males often resort to ostentatious displays to distinguish themselves from ...

Some birds may use their feathers to touch

February 15, 2010

( -- A new study of auklets suggests the birds use their ornamental feathers in much the same way as cats use their whiskers: to feel their surroundings.

Nest diet has big impact on attractiveness of hihi birds

February 13, 2013

Published today by the Zoological Society of London (ZSL) and University of Cambridge, the study reveals that male hihi birds develop more colourful and attractive breeding feathers if they receive a nest diet rich in carotenoids ...

The evolution of plumage patterns in male and female birds

December 18, 2013

( —Research published today looks at the evolutionary pathways to differences in bird plumage patterns between males and females – and concludes that birds are able to adapt their appearance with remarkable ease.

Recommended for you

Study shows how giraffe assassin bugs outwit spider prey

October 26, 2016

(—A biologist at Macquarie University in Australia has discovered the secret behind the giraffe assassin's ability to catch and kill spiders in their webs. In his paper published on the open access site Royal Society ...

New analysis of big data sheds light on cell functions

October 26, 2016

Researchers have developed a new way of obtaining useful information from big data in biology to better understand—and predict—what goes on inside a cell. Using genome-scale models, researchers were able to integrate ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.