ScienceShot: Birds Bend Light to Woo Females

When a male Lawes's Parotia shakes a tail feather, the ladies and the physicists take notice. Living in the rainforests of Papua New Guinea, males of the species (Parotia lawesii) wear a coat of velvety black feathers, with the exception of a colorful, shimmering spot on their breast. For their mating display, they head to a patch of sunlight and strut their stuff in a so-called ballerina dance, spreading their feathers like a tutu and shaking their body to shimmer their breast plumage. The striking breast feathers get their iridescent properties from tiny boomerang-shaped structures called barbules. The barbules act like three-sided mirrors, shining blue-green or orange-yellow light depending on the position of the observer. Now, a team of computational physicists has used cutting-edge photosensors and computer modeling to analyze the barbules’ light-bending properties in real time. The team discovered that the vibrant light from the breast feathers selectively activates different photoreceptors in the female birds’ eyes as the colors change. When the male birds dance quickly, the females are treated to a barrage of shiny colors as their visual receptors activate in quick succession, the researchers report online this week in the Proceedings of the National Academy of Sciences. The team believes that over many generations male Lawes's Parotia tuned their flashy feathers and dance moves to the females’ visual system.

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