Fake It 'Til You Make It
How tropical tanagers cheat their way to flashier feathers and hopefully more mates
There’s a reason peahenning isn’t a thing. In birds, it’s typically up to the males to impress potential mates through incredible displays of color showcasing their fitness. For males of the Ramphocelus genus of tanagers found in Central and South America, it's brightly colored feathers that earn the birds common names like "scarlet-rumped" or "lemon-rumped" and "flame-rumped."
These rumps aren't supposed to just be good-looking, either. Bird scientists have long theorized that this coloration represents a healthy diet full of foods which make these bright bottoms possible. In a new article in the journal Scientific Reports, NHM’s Assistant Curator of Ornithology Allison Shultz and colleagues reveal that these tropical birds have one weird trick to enhance their vivid color.
The implications go beyond bright colors, Shultz says. “We don’t know what else is happening with these. Does having these different feather shapes make it easier for parasites to attack them? Or harder? We don’t see this super black structure around us, just in the tropics. Is there a thermoregulatory reason? ” Super black has evolved in many birds in different locations, possibly playing different roles in things like heat retention as well as attracting mates. Shultz’s research has opened the door to understanding even more about what roles feathers play.
So what other birdy beauxs might be pumping up their luster with clever microstructures? “Microstructure could apply beyond carotenoids too,” Shultz says, but she plans on starting with other colorful birds, and collections like NHM’s make that possible. Kept safely in their shelves away from light and dust, the feathers in ornithology collections are waiting to tell the story of birds and color. “In order to really get at this, you’d need to sample many species across the world, and it would be logistically impossible to do that in the field. In museum collections, we already have the samples, with over half of bird species in our collection alone.”