In a clearing where an ancient Mayan city once stood, the Montezuma Oropendola perches and sings. His courtship display is astonishing: he swings by his feet and sings, his tail describing a golden pendulum – the very source of his name in Spanish – oropendola.

The White-vented Storm-Petrel is a small black and white seabird found off the coasts of Chile and Peru. Storm-petrels spend their entire lives at sea, except when nesting. Scientists had long been mystified about just where this species nests. A search lasting eight years led them to a…

Once abundant around San Francisco Bay, the Ridgway’s Rail — formerly known as the California Clapper Rail — is now endangered. In the 19th Century, unregulated hunting plundered the species. In the 20th Century, rampant development reduced salt marsh habitat by 85%. But in the 21st…

Let’s talk about nests. Every spring, robins build their cup-shaped nests using grass and mud. Orioles weave a hanging sack. It’s hard work, and yet once the chicks fledge, the structures probably won’t be reused. But bigger birds, such as herons, hawks, and eagles, often reuse a nest for…

American Goldfinches are one of our most familiar birds, but they lead lives that are anything but ordinary. These birds will sometimes raise two broods a year, have a secret weapon against cowbirds, and have the ability to distinguish between songs that — to our ears — sound the same…

In September, this Arctic Tern flies from Alaska all the way to Antarctica. Rufous Hummingbirds follow pathways of mountain wildflowers, from as far north as Alaska south to Mexico. Ruby-crowned Kinglets, migrate altitudinally from the mountains to the lowlands. Each of these birds…

Algunas noches despejadas en septiembre, cuando el aire es claro, ¡puedes mirar aves cruzando la luna amarillenta! Septiembre es el pico de la migración para millones de aves cantoras dirigiéndose hacia el sur, de América del Norte a latitudes más tropicales. Migrantes nocturnos de las…

How does a robin know a worm is in one exact spot? Does it see the worm or hear it? Smell it? Sense its movements through its feet? To find the answer, researchers buried worms in soil in a tray. They covered the soil with a thin but opaque sheet of cardboard, followed by more soil, so the…

Para inicios de agosto, el amarillo brillante de las plumas de la Reinita de Wilson parece destellar en cada matorral del bosque. A pesar de los depredadores y el clima, muchas parejas de adultos han criado cuatro jóvenes, que ahora revolotean por sí mismos. Los jóvenes machos que nacieron…

At a glance, swallows and swifts, both graceful fliers, look much alike. But swifts — like this Chimney Swift — have longer, slimmer wings and short bodies, enabling them to glide for long periods. Their glides are punctuated by rapid, stiff bursts of wing-beats. Swallows, on the other…