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…

The range and abundance of the Great-tailed Grackle have expanded significantly since 1900, when the species barely reached Texas from Mexico. One winter roost of grackles in South Texas was pegged at 500,000 birds! Great-tailed Grackles can present pest management problems for agriculture…

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…

Washington Irving called the Bobolink "the happiest bird of our spring...he rises and sinks with the breeze, pours forth a succession of rich tinkling notes ..." Bobolinks nest in hayfields and grasslands, returning north each spring, all the way from southern South America. Listen to more…

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…

This Golden-cheeked Warbler nests only in a Central Texas woodland. Its small breeding range is ever more fragmented by residential development, and its numbers are in serious decline. Endangered Species Day was established by Congress to acknowledge the plight of this warbler and many…

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…