Why are Tropical Birds so Colorful?
- Author
- Kyle Schiber, Nature Museum Volunteer
- Date
- January 22, 2018
Parrots, macaws, parakeets… these rainbowed tropical birds put to shame the brown and gray birds that are so common in Illinois and Chicago. Even Chicago’s brightest birds—cardinals, blue jays, gold finches—are vibrant, but single-colored. Why are bright and multi-colored birds so common in tropical rain forests, and nowhere to be found in temperate climates like Chicago? Do the changing seasons make bright birds sitting ducks in the winter? Do jungle birds eat bright berries and fruits instead of brown and black seeds? What gives?
We can eliminate one option right away: a parrot’s color has nothing to do with its diet. While a flamingo gets its pink color from the food it eats (brine shrimp and blue-green algae) and a cardinal is red in part because of the seeds in its diet[2], a parrot’s color is determined by its genes.[3] The incredible colors of the blue-and-yellow macaw do not come from tropical mangoes and imported blueberries.
It must be some other quality of the tropics that creates brighter birds: is it the rainfall? The year-round high temperatures?
This Northern Cardinal is just one color: red. No one is flocking to see this bird in a zoo. Coincidence? No.[1]
Sorry about the awful pun in that other caption. Here, have a picture of an ivory-billed aracari.[4]
This red-crowned ant-tanager is related to the cardinal. It lives in the rainforests of Central and South America, and it is less bright than the Northern Cardinal.[6]
The truth is that tropical birds don’t tend to be more colorful. Dr. Nicholas Friedman of the Okinawa Institute of Science and Technology explains, “if you look at birds in the tropics, there are a lot of colorful birds that stand out. But there are really more species in general there, and there are just as many more of the little brown ones”.[5]
In other words, the tropics are much more diverse in general than temperate or dry climates. The rainfall and year-round high temperatures contribute to rainforests having many more animal and plant species than other places. Of these many more animal species, some are brightly colored birds, but there are even more species that are plainly colored. The birds that are exported from the rainforests for zoos or as pets are the brightest birds, and these are the tropical birds that we in Chicago are familiar with. This leads to the overall impression that birds from the rainforest are more colorful as a rule, even though it’s not actually true!
If you want to know more about tropical birds or even to see them up close, head to The Bird House exhibit at the Peggy Notebaert Nature Museum between now and June 18th to see some colorful birds you can’t find in Chicago’s trees. You can even see an ivory-billed aracari like the one pictured above!
Sources
[1] https://commons.wikimedia.org/wiki/File%3AMale_Northern_Cardinal_-_Manhasset%2C_NY_04.jpgBy Chris Hachmann (Own work) [CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0)], via Wikimedia Commons
[2] Koren, Marina. “For Some Species, You Really Are What You Eat”. (April 24, 2013). Retrieved January 8, 2018, from https://www.smithsonianmag.com/science-nature/for-some-species-you-really-are-what-you-eat-40747423/
[3] Cooke, Thomas F. et al. “Genetic Mapping and Biochemical Basis of Yellow Feather Pigmentation in Budgerigars”. Cell , Volume 171 , Issue 2 , 427 – 439.e21. Retrieved January 11, 2018, from http://www.cell.com/action/showImagesData?pii=S0092-8674%2817%2930941-8
[4] https://download.ams.birds.cornell.edu/api/v1/asset/51034071/largeBy Glenn Bartley. Retrieved from https://neotropical.birds.cornell.edu/Species-Account/nb/species/ivbara1/overview on 1/21/2018
[5] Okinawa Institute of Science and Technology Graduate University – OIST. (2016, November 4). “Plumage evolution: Explaining the vivid colors of birds.” ScienceDaily. Retrieved January 18, 2018 from www.sciencedaily.com/releases/2016/11/161104101848.htm
[6] https://commons.wikimedia.org/wiki/File%3AHabia_rubica_-_Red-crowned_Ant-Tanager_(male).JPGBy Hector Bottai (Own work) [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons