The ability to fly seems to define birds. But there are more than 50 species of flightless birds throughout the world — from the Ostrich and Kiwi to flightless rails, ducks, and this Humboldt Penguin. Why did they evolve the inability to fly? Many dwelt on islands. Others evolved until…

La mayoría de las aves mudan y regeneran sus plumas de vuelo, una a la vez en cada ala, para mantenerse en óptimas condiciones para volar. Pero para el albatros viajero ( Diomedea exulans), que tiene una impresionante envergadura de entre 3 y 4 metros, ¡es un gran desafío! A los albatros…

Chickadees are tiny songbirds named for their characteristic song and there are seven species found in North America. You'll find the Black-capped Chickadee across the northern US into Canada. The Carolina Chickadee holds sway in the Southeast. Hear the husky voice of a Mountain Chickadee…

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…

Northern Mockingbirds can learn to mimic the sounds of just about any bird. They mimic to show off, not to deceive. But this Thick-billed Euphonia, a tiny songbird in South America, employs what scientists call “deceitful mimicry.” When frightened by a predator near its nest, a Thick…

Si los vuelos migratorios de larga distancia ya son asombrosos, lo que ocurre dentro del cuerpo de un ave durante esos vuelos parece, sencillamente, increíble. Para almacenar grasa, muchas aves comen hasta tres veces más de lo normal y buscan alimento durante muchas más horas, mientras se…

Si las plumas de un ave se secan demasiado, se vuelven frágiles. Para evitarlo, la mayoría de las aves tienen una glándula situada encima de la base de la cola que produce un aceite. Usan sus picos para masajear el aceite desde la glándula hacia las plumas, para mantenerlas flexibles. Un…

In June 1853, Thoreau wrote of an enchanting encounter with the Wood Thrush: "This is the only bird whose note affects me like music. It lifts and exhilarates me. It is inspiring. It changes all hours to an eternal morning." Wood Thrushes thrive in large expanses of forest. And their…

European Starlings were present in great numbers in ancient Rome. They swarmed in massive flocks or murmurations — thousands of individuals cascading and folding in awe-inspiring geometric patterns in the sky. Roman augurs, or diviners, scrutinized these patterns for signs of how the gods…

In 1956, the Eisenhower Administration announced plans for the nation’s new interstate highway system. Planners foresaw 41,000 miles of superior highways, with a grassy border on either side and down the middle. The grassy areas created ribbons of wildlife habitat occupied by small mammals…