Strutting like a peacock

Male peacocks fan their spectacular tail feathers in order to capture the attention of females. But what do the hens find so attractive about these elaborately decorated, erect tails?
A scientist from California wanting to know more on the subject developed a small helmet with two cameras for the head of the peahen. The one camera filmed what the hen looked at, and the other camera registered her eye movements. The camera batteries were placed in a small backpack, together with an apparatus for sending the images to a computer. After a period of practice, the cameras were in working order, and the eye movements of the hens could be tracked accurately. What followed were various experiments in which peahens were confronted with peacocks, and the results were remarkable. While a male is doing his best to show off his heavy tail feathers, the female only looks at him about a quarter of the time. The rest of the time she is observing her surroundings. And when the female does look at the male, she mainly looks at the bottom layer of feathers. Most likely, writes the scientist, the female gathers a great deal of information about the male from the lower feathers. She sizes up the symmetry and the size of the plumage, which allows her to deduce how old the male is.

Are the rest of the plumes useless? No. While the researcher was visiting natural peafowl habitat in India, she saw that the cocks make themselves visible in tall grass by fanning their tails. This allows the hen to find the cock and decide to approach him. However, only after the female has seen the male’s underside and likes what she sees does she decide that mating can follow.