In the early 1980s, the city of Austin, Texas needed to enlarge its Congress Avenue Bridge. The new bridge design included expansion joints that inadvertently created roosting cavities for bats - tiny Mexican Free-tailed Bats - eventually one and one-half million of them! At first, many…

Brown-headed Cowbirds lay their eggs in other birds' nests. And these birds raise the cowbird chicks - often at the expense of their own young. This beautiful Yellow Warbler is a frequent target of the cowbird's unwelcome eggs. But it has developed a way to reject the role of foster parent…

Williamson's Sapsuckers nest in western mountain forests. The radically different plumages of the male and female so confounded 19th-century naturalists that, for nearly a decade, the birds were thought to be of different species. Sapsuckers are unique among woodpeckers in drilling neat…

Red flowers, and of course red feeders, are often rich sources of food for hummingbirds, including this Broad-tailed Hummingbird. Nectar is high-octane fuel for their intensely active way of life. The hummingbirds' sense of color is due to the dense concentration of cones in its retina…

As the sun sets on a northern Midwest forest, an American Woodcock walks slowly from the cover of the forest to a nearby clearing. Then, the woodcock takes off on a courtship flight. At the apex of its flight, the woodcock circles, then descends in a slow spiral, putt-putting like a tiny…

A male Montezuma Oropendola holds forth in a tree bedecked with twenty or more hanging nests. The nests are intricately woven sacks hanging three feet or more from the branches. Oropendolas favor trees that are separate from other trees and often build near large nests of wasps, whose…

At a display area, known as a lek, the male Greater Sage-Grouse perform for mating rights, while the smaller females look on. Today, the Greater Sage-Grouse is seriously endangered, its fate intertwined with the loss of sage habitat. Millions of acres have been converted to cropland, and…

What an amazing noise! Whistles and trills, squeaks, rattles, and gurgles that suggest an orchestra of birds tuning up in the urban forest. You look around – not a bird in sight. The sounds waver in intensity, but with no clear pattern. Perplexing, but strangely wonderful! Suddenly, a…

A chill wind ruffles the feathers of a male Sagebrush Sparrow (formerly known as the Sage Sparrow), as he sings atop a tall sagebrush. It is late February, a few miles from the Columbia River in Central Washington. Sagebrush Sparrows are arriving north from wintering in the Southwestern…

American Bird Conservancy and other organizations are working to make Hawaiian birds a top national priority for conservation. Of all the endangered bird species in the United States, more than one-third are found only in Hawaii. Biologists on Hawaii's Big Island are working to restore…