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Green Birds and Brown Birds in the Tropical Rainforest
A fundamental of Darwinian evolution
© Terje Grimsgaard
The canopies of the world’s tropical rainforests are green year round. So are many of the birds within them, from parrots and hummingbirds to trogons and jacamars, such as this Rufous-tailed Jacamar. Being green in the tropics helps birds blend in to their surroundings, which is especially important for those that spend their time among the glossy leaves. Tropical birds that live near the forest floor, however, sport drab plumage of brown, gray, and black. Even the hummingbirds of the understory, known as hermits, are camouflaged in earth tones.
BirdNote®
Green Birds and Brown Birds
Written by Bob Sundstrom
This is BirdNote.
[Rainforest ambient]
The canopies of the world’s tropical rainforests are green year round. [Mealy Parrots, http://macaulaylibrary.org/audio/68674]
So are many of the birds within them, from mostly green parrots and sparkling, iridescent hummingbirds, to trogons [pronounced tro-gahnz] and jacamars [JAK-uh-mahrz], with their shiny green backs. [Collared Trogon song, http://macaulaylibrary.org/audio/113241]
Their coloring underscores a fundamental of Darwinian evolution: “that an organism’s appearance, behavior and physiology must be adaptive to contribute to a greater overall level of reproductive success.” In other words, being green in the tropics means you won’t stand out and you have a better chance of reproducing, especially if you spend much of your time among the glossy leaves up top. [Mealy Parrots, http://macaulaylibrary.org/audio/68674]
As for the vividly colorful birds found throughout the tropics, put them inside the forest, and their iridescent coloring becomes a dark disguise. Tropical birds that live in the shadows near the forest floor—antbirds, ovenbirds, and wrens—sport earth-tones of brown, gray, and black. Even the hummingbirds of the understory, known as hermits, wear drab plumage of gray, or brown, or only the dullest green. Camouflage almost as well suited for the deciduous forests of the north as the rainforests of the tropics.
For BirdNote I’m Michael Stein.
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Bird sounds provided by The Macaulay Library of Natural Sounds at the Cornell Lab of Ornithology, Ithaca, New York. Mealy Parrots [68674] recorded by Paul A Schwartz; Collared Trogon recorded by Curtis A Marantz.
BirdNote’s theme music was composed and played by Nancy Rumbel and John Kessler.
Producer: John Kessler
Executive Producer: Dominic Black
© 2015 Tune In to Nature.org December 2015 Narrator: Michael Stein
ID# plumage-01-2015-12-14plumage-01
Source: Birds of Tropical America by Steven Hilty
Bob Sundstrom
Writer
Michael Stein
NarratorRelated Field Notes
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