When scientists looked at climate data for more than 8,500 robins’ nests in the US, they found that robins will nest only if the mean noon temperature is between 45 and 65 degrees. But even more critical is relative humidity: it needs to be around 50 percent in the middle of the day. What…

When it comes to building a house, one of the first decisions is where to put it. The same is true for birds. It's called "nest site selection." And one thing most birds have in common? The female chooses the site. A robin builds its nest on top of a stout branch. This Warbling Vireo hangs…

All birds lack the typical gene for detecting sweetness, but hummingbirds avidly seek out sugary nectar. It turns out that evolution has transformed hummers’ taste receptors. Mutations to their savory taste receptor gene allowed the receptor to respond to sucrose and other sugars…

A Tufted Titmouse has just about everything you could ask for in a backyard bird. Petite and strikingly elegant, it’s as perky as a chickadee. In fact, it’s a cousin to the chickadee. And as it comes boldly to your seed or suet feeders, the Tufted Titmouse will even hang upside down like…

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…

Red-tailed Hawks are found year ‘round in a wide variety of natural landscapes, from meadows to forest edges, deserts, and canyons. One big reason we see Red-tailed Hawks in so many places is their remarkable adaptability as hunters. They vary their diet to what is locally abundant. So…

The dense cover of coastal chaparral supports many birds found nowhere else in the world, including this California Thrasher. The plant species are different, but the chaparral of California is much like shrubby coastal vegetation in southern Europe, South Africa, southern Australia, and…

The Canyon Wren and Cactus Wren share common ancestry — and they’re close neighbors in the desert southwest. Yet their songs evolved along divergent acoustic lines. The rough trilled phrases of the Cactus Wren song pulse through the dense cactus, while the clear tones of the Canyon Wren…

Almost half of all migratory shorebirds nesting in North America migrate through the Cheyenne Bottoms Wildlife Area in central Kansas. Almost all of the continent's Wilson's Phalaropes rest and refuel at the wetlands here. The birds fly a great oval route. In autumn, in the East, they head…

In the mid-1990s, a golden age of fossil discovery began in the Liaoning region of northeast China. The fossils date from 120 to 160 million years ago, when feathered dinosaurs and early birds were flourishing and differentiating. The signature fossil was the world’s first-known feathered…