The hooded pitohui is one of the few known toxic birds. Like poison dart frogs, it builds up toxins in its body — likely from beetles that it eats — storing them most potently in its feathers which can cause an itching, burning, and numbing sensation when touched.

The island canary — native to the Canary Islands, Madeira, and the Azores — is the wild ancestor of the domestic canary. It was bred to be garishly coloured, to have different haircuts and postures, and to imitate the songs of other birds or the sound of babbling water. Later, it was used to detect dangerous gases in coal mines.

The eastern and western meadowlarks look nearly identical, behave in the same way, and share similar habitats — even overlapping in range in the central plains of North America — yet they are separate species that rarely interbreed. What keeps them apart are the different songs they sing.