In higher animals, the brain is like a Lamborghini — amazing engineering, but expensive to run. In a human, the brain uses about 10 times more energy than other organs. A bird's system is exquisitely attuned to this expense. Several species, including Black-capped Chickadees, have adapted…

May is the prime month across much of North America to celebrate the return of migratory birds from the tropics. Of all those coming back, it is the warblers that many birders eagerly await. And of the more than 50 species that brighten our spring, many gleam like precious stones. From the…

The fluting song of the Wood Thrush is an ethereal sound of summer in North America. During the breeding season, these robin-sized songsters serenade deciduous forests of the eastern U.S. and Canada. Each fall, they migrate to rainforests from southern Mexico to Panama where they call to…

There may be no busier bird during the nesting season than a male House Wren. Just a day or so after completing his spring migration from the tropics, the male House Wren claims a territory and checks out several potential nest cavities. And in each of these locations, he builds a starter…

Peer into the world of birds, and eyes of many different colors peer back. While eye color isn’t tied to one group of birds or another, a common pattern is a change in eye color as immature birds grow to adulthood. Bald Eagles, Ring-billed Gulls, and ducks such as goldeneyes and scaup have…

In spring, millions of songbirds — like the Orchard Oriole — migrate north across the Gulf of Mexico, from the Yucatan to the southeastern U.S. When birds encounter storms or headwinds, many may die. Why risk such an end, when they could migrate north along the length of Mexico? It's…

The Scissor-tailed Flycatcher nests in the open country of Texas, Oklahoma, and the south-central region. It's an elegant bird with a slender, deeply forked tail longer than its body. Agile in flight, it can spread and fold its tail, altering the surface area, like an extra pair of wings…

Pigeons, one of the most ancient of domesticated animals, feed their nestlings a peculiar, milky substance, straight from the adult’s beak to the baby’s throat. It’s called pigeon milk, a fat-rich substance loaded with antioxidants and immunity factors that enhance the survival of newborns…

Este búho pequeñito, llamado tecolote serrano o mochuelo gnomo ( Glaucidium gnoma), parece tener ojos en la parte de atrás de la cabeza. Pero, ¿por qué? Una teoría sugiere que esos grandes ojos falsos crean la ilusión de que el búho es mucho más grande de lo que realmente es: apenas mide…

Rachel Carson found inspiration in the work of 19th-century writer Richard Jefferies, whose work helped Carson develop her deep sense of connection with the natural world. Jefferies wrote: "Consider the grasses and the oaks, the swallows, the sweet blue butterfly — they are one and all a…