Today’s Question: Why are tropical birds so colorful?
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, a parrot’s color is determined by its genes. 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?
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”.
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!