Sometimes populations of birds split apart - a process called speciation. Where Baltimore Orioles and Bullock’s Orioles overlap in the Great Plains they produce hybrid offspring. But these hybrids don’t live very long or spread very far. Are these two birds different species?

For many birds, breeding and nesting are tied closely to spring. But for a bird like the White Ibis — one of the most abundant wading birds in the Southeast — the timing of nesting has to do with water. White Ibises forage in shallow pools of fresh water, especially for crayfish and small…

When young hens begin laying at five or six months, their ovaries aren’t fully in synch. So every hundred or so eggs, they release two yolks instead of one. Double-yolk eggs are usually a little bit larger than average, so if you’re looking to get one, try buying the extra-large or jumbo…

In 1559, Duke August of Saxony ordered that the House Sparrows of Dresden be excommunicated. The birds were slipping into Holy Cross Church, where they interrupted the sermon with exuberant chirping and “endless unchaste behavior” before the altar. Now their manic chirping and courtship…

A Burrowing Owl is about as big as a can of beans on stilts. Between the long legs, bright yellow eyes, and signature bobbing salute, these little birds are comical members of the western ecosystem. Cowboys riding Western rangelands have a nickname for these little owls. They call them…

In summer, across much of North America, a sudden flash of orange and black in the treetops usually means one thing: orioles. Baltimore Orioles (like this one) in the East, Bullock’s Orioles in the West, and Hooded Orioles in the Southwest and California. These vividly colored birds return…

The real James Bond was born in Philadelphia in 1900 and worked as a banker after college. But his first love was the natural world. Eventually, he kissed the banking world goodbye and dedicated the rest of his life to exploring and documenting birds and nature.

A Rock Pigeon bobs its head as it walks, making it appear that its head and feet are linked. Pigeons' eyes are on the sides of their heads, permitting them to watch for predators from all directions, but limiting their ability to distinguish distances. To compensate, these birds move their…

It’s more important than ever to map their travels – to learn when birds take flight, where they stop to rest, and what they require for food and shelter along the way. New tools like advanced weather radar, crowdsourcing, and geolocators are helping us learn more about where birds go and…

Immature Bald Eagles look so different from mature Bald Eagles that John James Audubon thought they were a different species entirely! Sitting about three feet tall, these majestic birds have wingspans of more than six feet. Stretch your arms as far as you can, and imagine a bird whose…