The Tree of Avian Evolution

What you read in the next few minutes might surprise you. It did for me, even as a lover of the study of biology and an avid birder.

As Eliot Miller stated in Living Bird (Cornell Lab magazine), “Evolution works in somewhat mysterious ways.” Two birds that look alike, could be separated by millions of years on the evolutionary scale. The same goes for birds that are close evolutionary cousins, living on opposite ends of our planet.

On the one hand, divergent evolution is pushing closely related species away from each other; natural selection (the race to enhance survival, such a being better at exploiting food resources or evading predators) pushes birds to gain an advantage by looking different or moving someplace different.

On the other hand, convergent evolution can push distantly related species to resemble each other. Again, natural selection is a driving force. Bird species that eat flying insects tend to have similar aerodynamic body shapes (even if they aren’t close relatives), kind of a like how different kinds of aquatic animals, such as fish and whales, similarly evolved elongated bodies and fins for swimming underwater.

This can lead to many surprises for birders (such as myself) when we dig into relationships of some of our favorite birds.Thus, let’s see what your answers will be to the following questions about our avian friends via this PDF file.