By using eye tracking technology and tiny cameras mounted on a customised cap, Jessica Yorzinski, a researcher at Purdue University, has been able to get a bird's-eye view of where a peahen looks when a peacock is displaying.
Two cameras and an infrared LED were attached to the head of the peacock to make the measurements. The cameras picked up the infrared light reflected by the peahen's retina in order to calculate where the bird was looking.
The peacocks have a tough time keeping a peahen's attention as she evaluates her surroundings for food and predators, but the peacocks did have one way to turn heads, Yorzinski said.
Although peacocks are famous for tall tail feathers with colourful eyespots, Yorzinski says peahens look lower when sizing up a male and that dance moves may give a suitor an edge.
‘What garnered the most attention from the peahens was when the peacocks would turn around and shake their wings and rattle their tails during the courtship dance,’ she said. ‘It seems that mastering certain dance moves is important for peacocks.’
‘Surprisingly, the peahens are looking at the lowest edge of tail feathers and aren't paying much attention to the rest of the five-foot tall displays,’ said Yorzinski, who is a postdoctoral fellow in the Department of Biological Sciences at Purdue University. ‘According to our study, the females' gaze rarely fell at or above the peacocks' heads. Of the small portion of time spent looking at the males, females looked longest at the legs and lower portion of the train.’ Yorzinski speculates that the peahens are assessing the size and symmetry of the lower portion of the male’s display.
The famously large tail plumes are still important; until a male is five years old, his train grows slightly larger each year, so size would matter for finding the older guys, she says. Also in a natural environment with high grasses, the top of the peacock's fan seems to be useful for hailing females at a distance to the dancing area, called a lek. But once she's in the lek, where the real selection happens, she's looking at the lower portion of the display. He shakes and dances and makes a rattling sound to help hold her attention.
The next phase of the experiments will entail altering the males' displays with scissors, adding eyes, or artificial colours to see what variables matter most. Males grow a new fan every year, so the bad haircuts won't do them any harm, Yorzinski says.
