Courtship and female choice are only part of how birds reproduce. The other part is conflict, and the anatomy it has produced is some of the most remarkable evidence in evolutionary biology.

Crossbills turn up when they feel like it, in any month, and then vanish. Here is what decides where they go, when they breed, and how you can find out which population you just met.

The birds we hold up as models of lifelong partnership do leave each other, and the conditions that make them do it turn out to explain a great deal about how pair bonds work.

Some male birds own nothing, defend nothing, and raise nothing. They gather on a shared stage, dance, and let the females decide. Here is how that system works and why it produces the most extravagant birds alive.

Courtship is the most watchable thing birds do, and the most easily ruined by watching it badly. Here is how to find displays, how to behave at them, and what to carry.

A Song Sparrow feeding a fledgling twice its size is not a bird being stupid. It is the visible end of an evolutionary contest that has been running for millions of years.