Peak bird migration is about to start in Colorado and around the country. Here are tools for tracking and identifying the millions of migrants.

Vocal and plumage variation in the Bewick’s wren is extensive ... buzzier. Songs of birds in the interior subspecies-group (ero­moph­ilus group) are simpler than those from the far West ...

Migration: most birds in North America migratory. Major spring movement follows that of the winter wren; major fall movement precedes that of the Winter. Winter: generally as breeding, but with ...

When summer’s bounty of bugs, seeds, and nectar starts to wane, most birds in Colorado seek warmer climes with good food to offer. But one group of birds sticks it out year-round, subsisting on ...