The Olive Warbler (Peucedramus taeniatus) is a unique small bird, and the sole member of its family, Peucedramidae, found from southern Arizona and New Mexico down through to Nicaragua. This insect-eating bird has a distinctive look, with males featuring a grey body with olive-green wings and a tawny-orange head and breast, while females and juveniles sport a yellow instead of orange, with a less defined black eye patch. The species shows size variation along its range, with northern populations being larger, an example of Bergmann's rule. Olive Warblers favor coniferous forests and vary in elevation from 1,000 meters in Nicaragua to over 3,500 meters in other parts. They typically reside year-round in their habitat, yet some northern birds exhibit partial migration during winter. Their song is a series of clear whistles, and males sing more frequently in late winter through early spring. While the Olive Warbler was once considered a New World warbler, DNA studies have revealed its distant relation to other passerines, leading to the bird being classified in its own family, defined by its unique skeletal and muscular features and early divergence from related bird groups.