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Are Peacock Eyespots Eye-Catching For Predators? | Science Trends

Are Peacock Eyespots Eye-Catching For Predators?

Ever since Darwin, the vividly colorful feathers used by many male birds to attract females have been assumed to attract predators as well. However, a new study published in PLOS ONE indicates that these ornaments are not necessarily eye-catching to predators after all.

A team of scientists led by Suzanne Amador Kane used specialized imaging and computer modeling to show how colorful feathers from peacocks and parrots appear in the eyes of other animals. To female birds, these feathers are as conspicuous as ripe fruit — a good thing for a male bird hoping to catch the attention of potential mates. For wild cats and dogs, however, the researchers found that the flashy feathers were not easily detectable against a background of green leaves and grass.

Three views of peacock eyespot feathers: Top left: photograph of a peacock displaying to a female shows how humans see these feathers. Bottom left: The primary predators on adult peafowl are wild dogs and cats, like this leopard. Simulated photographs based on color vision modeling provide insights into how these feathers appear to peafowl (top center and right) and their predators (bottom center and right). Image credits: Top left: Roslyn Dakin; bottom left: Srikaanth Sekar, Creative Commons Attribution-Share Alike 2.0 Generic License; all others: Yuchao Wang.

These surprising results are due to differences between the visual systems of these animals. Cats and dogs are red-green colorblind — they have only two of the three types of color-sensitive cone cells that most humans have in the retina — so these predators perceive many yellow, orange, and red feathers as being similar in color to green leaves. By contrast, birds have four types of cones, each with sensitivities well-suited for distinguishing different feather colors. Compared to birds and humans, these predators also see the world as blurrier, with less variation between dark and light, so even vivid green and blue peacock feathers appear muted. Like birds, these predators have the ability to see ultraviolet light, a part of the spectrum that is invisible to humans, but that superpower isn’t enough to help them detect colorful plumage.

Darwin wrote that “[e]ven the bright colors of many male birds cannot fail to make them conspicuous to their enemies of all kinds,” but these new results show birds that appear vividly colorful to humans and other birds can appear drab and inconspicuous in the eyes of mammalian predators. Together with another recent study that showed conspicuously colorful plumage does not enhance the risk of attack by birds of prey, this suggests that being colorfully sexy is not the main risk these colorful birds face.

These findings are described in the article entitled How conspicuous are peacock eyespots and other colorful feathers in the eyes of mammalian predators? recently published in the journal PLOS One. This work was conducted by Suzanne Amador Kane, Yuchao Wang, Rui Fang, and Yabin Lu from Haverford College, and Roslyn Dakin from the Smithsonian Conservation Biology Institute.

About The Author

Suzanne Amador Kane

Suzanne Amador Kane is a physicist and Professor and Chair of Physics and Astronomy at Haverford College. She is well known for her work utilizing video to understand the behavior of various species of birds.

My research interests lie at the interface of biological physics, soft condensed matter physics and statistical physics. My research projects have included studies of how animals use visual guidance during predator pursuit and prey evasion, the biomechanics of peacock mating displays, the kinematics of raptor take-off flight, how birds signal by calling during flocking, computer modeling of bacterial diversity in ecosystems, and biologically-inspired nanostructures. My students and I approach these problems using a combination of experimental techniques, including high-speed and stereometric 3D video, bioacoustics and computational modeling. Before coming to Haverford, I focused on using scattering techniques (x-ray and optical) in the study of biological membranes and low-dimensional soft matter systems.

Roslyn Dakin

Roslyn Dakin is a postdoctoral fellow with the Smithsonian Conservation Biology Institute’s Migratory Bird Center. The goal of her research is to understand how the physiological mechanisms that drive behavior evolve, and how this allows organisms to respond to diverse challenges in nature. To this end, she develops high-throughput behavioral assays that can be linked experimentally to physiology at the biomechanical, neurological, endocrine and molecular levels. At SCBI, Dakin works with Brandt Ryder to study the social behavior of wire-tailed manakins. This work leverages Ryder’s proximity logging system to track the movements of an entire population of manakins during their cooperative courtship displays in Ecuador, to understand the factors that promote cooperation.