Passerines

Passerines, or perching birds, constitute the order Passeriformes, the largest group of birds with more than half of all living species. They are united by adaptations for perching, most notably anisodactyl feet with three toes pointing forward and one backward, which aids grasping branches. A defining feature of many passerines is the syrinx, allowing a wide range of vocalizations, especially in oscines (songbirds).

Within Passeriformes are two major clades: suboscines ( Tyranni ) and oscines (Passeri). Suboscines have relatively simple, innate vocalizations, while oscines have learned vocal repertoires and complex songs.

Passerines are distributed worldwide, absent only from the most extreme polar regions and some remote islands. They occupy habitats from forests and grasslands to urban environments. Their diets are diverse, including seeds, fruits, nectar, and arthropods, with many species showing seasonal or life-stage dietary shifts.

Reproduction typically involves pair bonding and nesting in vegetation, with eggs that are often camouflaged and altricial chicks. Many passerine species are resident, but others migrate between continents or hemispheres.

Evolutionarily, passerines diversified rapidly after their origin, with oscines expanding in diversity and geographic range due to their vocal learning. Notable families include Corvidae (crows and ravens), Parulidae (new world warblers), Turdidae (thrushes), Fringillidae (finches), and Passeridae (sparrows).