May in an Eastern hardwood forest, and the chorus of spring birdsong is nearing its peak. The Carolina Wren, a year-round resident, has been singing since the end of winter. The resounding notes of this Ovenbird let us know it has returned safely from Belize, after a long flight across the…

Los pericos barranqueros excavan túneles profundos para anidar en acantilados de arenisca y piedra caliza de Argentina y Chile. Muchos de los túneles de la colonia zigzaguean y se interconectan creando un intrincado laberinto. Sus colonias de anidación son de las más grandes entre los…

Birds like finches, chickadees and Northern Cardinals love sunflower seeds, but each species uses a different strategy to extract the meat. When a finch plucks a sunflower seed from the feeder, it uses its tongue to maneuver the seed lengthwise into a groove on its beak. As it closes its…

Cactus Wrens, which may nest several times between March and September, carefully orient their nests in tune with the season. These bulky twig structures have a side entrance that curves toward the inner chamber. When building a nest for the hot months, the wren faces the opening to…

Green-winged Teal are North America's smallest dabbling duck, at just over a foot long and weighing less than a pound. The male has a cinnamon brown head with a band of green behind the eye. Both males and females have a green bar on the wing that gleams like an emerald when the sun…

The eerie sound of the Great Tinamou can be heard in the lowland jungle throughout much of Central and South America. Secretive — and almost impossible to see — Great Tinamous call early and late in the day. And their voices carry a long distance.

When Cliff Swallows arrive on the breeding grounds in North America, the dirty work begins. The swallows scoop up mud in their beaks and carefully build a gourd-shaped nest with a tapered opening. They add a lining of dry grass to keep eggs warm. It takes days of work and a thousand…

Aplomado Falcons were once widespread residents of the American Southwest, but by the 1950s, they'd disappeared entirely from the region. Loss of habitat, loss of prey, and pesticides all played a role. But in the 1980s, a group called The Peregrine Fund began breeding captive Aplomado…

A hummingbird's brilliant throat feathers are called a "gorget," a term applied in past centuries to the metallic swatch protecting the throat of a knight-in-armor. Light waves reflect and refract off the throat feathers, creating color in the manner of sun glinting off a film of oil on…

The asteroid that struck the Yucatán 66 million years ago wreaked worldwide ecological damage, spelling the end for most dinosaurs and destroying the world’s forests. Yet a few bird-like dinosaur groups made it through. Scientists believe that these groups were all ground-dwellers. Though…