The magnificent plumage of the peacock may not be quite the sacrifice for love that it appears to be, researchers at the University of Leeds have found.
A team filmed five Indian peacocks using two high-speed video cameras to find out what price male birds pay for carrying the spectacular iridescent feathers they use in displays to attract females.
"These feathers weigh about 300 grams and can exceed 1.5 metres so it is expected that the male birds would be making a significant sacrifice in their flight performance for being attractive," explained Dr Graham Askew from the University of Leeds' school of bio-medical sciences.
For the study, Dr Askew filmed the take-offs of birds carrying full plumage in 3D and then filmed the same birds taking off without their display feathers.
The display feathers were cropped to judge the change in take-off performance between the two states.
To his surprise, there was no significant difference.
"These birds do not seem to be making quite the sacrifices to look attractive we thought they were," Dr Askew noted.
He observed the position of each bird's centre of mass, their wing motions and the movement of the display feathers 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 display feathers.
"Intuitively you expect that the display feathers would detrimentally affect flight performance and so not finding a detectable effect was a bit surprising," Dr Askew pointed out.
The display feathers of the peacock is one of the most iconic examples of sexual selection 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," concluded Askew.