Gyrfalcons are the largest falcons in the world, with a wingspan of almost four feet and weighing almost five pounds. The name “Gyrfalcon” derives from an Old Norse word for “spear.” During the summer, you’ll find Gyrfalcons on the tundra, where they feed on arctic birds. But in the winter…

The nuthatch’s beak is all business. Long, slender, sharp: it can pluck a tiny spider from a crevice in the bark or carve a nest hole right through the outer hide of a tree. And the Brown-headed Nuthatch is even known to use tools! Picking up a flake of pine bark in its beak, the bird uses…

En la región baja del Valle del Río Grande en Texas, donde el Río Bravo hace frontera con Estados Unidos, las aves que comúnmente se encuentran en América Central llegan a su rango norte más extremo. Aquí puedes encontrar aves fascinantes como este mosquerito chillón, un pequeño…

The Common Murre is among the few species of birds that can "fly" under water. When above the water, the 18"-long murre must flap frantically to stay aloft. But beneath the waves, with its flipper-like wings partly extended, it is a streamlined, masterful swimmer. Common Murres, black and…

In the warmer regions of the world’s oceans, large seabirds called boobies plunge headfirst into the water, snatching up fish. But as a booby flies up from the waves with a fish now in its gullet, there may be another big seabird — a frigatebird — with its eye on the booby’s fresh catch…

Developing eggshells requires a key ingredient — calcium — in larger quantities than the female typically has in her bloodstream. Just how different bird species supply or store calcium for egg-laying isn’t fully known. While some species seek out extra calcium from their environment, many…

Both the Willow Ptarmigan and these White-tailed Ptarmigan, feathered mostly brown in summer, are utterly transfigured by an autumn molt. As snow begins to mantle their world, both species, now all white, blend in superbly. But the ptarmigan pulls another trick. It adds dense white…

The word “dove” might make you think of an elegant bird symbolizing peace, while the word “pigeon” might bring up images of rowdy flocks of city birds. But there’s no formal distinction between doves and pigeons, only a linguistic one. In many languages, the birds are one and the same. The…

The treeswifts of India, Southeast Asia, New Guinea, and beyond make their nests out of bits of plants and feathers and hold it all together with some very sticky saliva. A treeswift’s whole nest is but a tiny cup — just large enough to hold a single egg — stuck to a bare upright branch…

By late January, some resident birds, such as the Northern Mockingbird, are beginning their spring singing. When you step outside on a particularly sunny day this winter, a Fox Sparrow like the one pictured here may be warming up for the coming spring. And as far north as British Columbia…