![]() ![]() ![]() Many hummingbird species have iridescent gorget (throat) feathers whilst other species are cloaked completely in a brilliant shimmering rainbow of eye-watering colors. In birds, iridescence is typically seen in pheasants, ducks, pigeons, kingfishers, a variety of songbirds, such as starlings and birds of paradise, lories ( ref) - and especially in those champions of iridescence, the hummingbirds. If the feather is tipped away from that angle, the feathers appear black or brown due to their melanin pigments. ![]() But iridescent feathers only create colors when light impinges upon the feather at a certain angle. The air pockets scatter light and the melanin pigments absorb a specific range of spectral light colors, which causes the feathers to reflect a single, very intense, color. These feather structures rely upon microscopic stacked layers of pancake-shaped melanosomes (special structures containing black or brown pigments) with tiny air pockets interspersed throughout. These feathers create a rainbow of ephemeral colors in the same way that a crystal prism does, or a thin layer of oil sitting on the surface of water. It is created by specialized microscopic structures inside feathers that split (refract) white sunlight into its separate spectral wavelenths, depending on the angle from which the feathers are viewed. (Diagram: Arizona State University School of Life Sciences 'Ask A Biologist'.) Arizona State University School of Life Sciences Ask A Biologistīut probably the most familiar example of structural color is iridescence. There are also tiny parts called barbules and hooklets that help hold the barbs together and give the feather its shape. the rachis, vane, afterfeather, barbs, downy barbs and the hollow shaft. The parts of a feather you can see with the unaided eye are. But how did the scientists come to this conclusion?į I G U R E 2 | Anatomy of a feather. The findings indicated that the range of colors in the plumage of hummingbirds exceeds the total color diversity of all other bird species - combined. Coe Professor of Ornithology and the Curator of Ornithology at the Yale Peabody Museum. I’ve written about bird colors before (more here, here, here, here and here.) And, as you’ve probably noticed, there are a lot of extremely colorful birds in the world, especially in the tropics (for example, more here), but which group of birds are the most colorful of them all? And how do they create their rainbow of plumage colors? These were the questions investigated by a team of scientists at Yale University (some members of this team have since migrated to new locations), under the guidance of evolutionary ornithologist Richard Prum, who is the W. Photos reproduced with permission of: a–f Glenn Bartley g Wilmer Quiceno h John Cahill. a Panterpes insignis, b Boissonneaua jardini, c Heliodoxa aurescens, d Lophornis ornatus, e Juliamyia julie, f Coeligena bonapartei, g Schistes geoffroyi, and h Atthis ellioti. hummingbirds analyzed, showing the incredible diversity of hummingbird plumage color, including saturated blues, greens, and purples. Photographs of males of eight of the 114. F I G U R E 1 | Diversity of hummingbird plumage color. ![]()
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