A passerine is any bird belonging to the order Passeriformes, commonly called perching birds or songbirds. Passerines make up more than half of all known bird species and occur across most terrestrial habitats worldwide, from forests and grasslands to cities. They are absent only from the most extreme polar deserts.

Key characteristics

Several traits are typical of passerines, although the group is diverse. Most have an anisodactyl foot—three toes pointing forward and one back—that aids perching. Many species possess a highly developed syrinx, the vocal organ that enables complex calls and songs. Size ranges widely, but many passerines are small; diets include insects, seeds, fruit, nectar, and omnivory depending on the species.

Taxonomy and subgroups

The order is usually divided into three principal suborders: Passeri (oscines or true songbirds), Tyranni (suboscines), and the small Acanthisitti (New Zealand wrens). Oscines are notable for learned song repertoires, while suboscines generally have more innate vocal patterns. For a general overview of birds see bird resources.

Origins and evolution

Passerines probably began a major diversification after the end-Cretaceous extinctions and radiated widely during the Cenozoic. Fossil evidence and molecular studies suggest multiple radiations that produced the many families and forms seen today, adapted to a variety of ecological niches.

Ecology and human relevance

Passerines play important ecological roles as insect predators, seed dispersers and pollinators, and they are common subjects in behavioral and ecological research. Their songs and conspicuous presence have long made them familiar in culture, literature and citizen science.

Notable examples and distinctions

  • Well-known families include sparrows, finches, warblers, thrushes and corvids (crows and ravens).
  • Size extremes range from tiny wrens to larger corvids; plumage and behavior vary greatly across families.
  • Conservation status varies: some passerines are abundant in human-altered landscapes, while others face habitat loss and decline.

Because passerines are so numerous and varied, they continue to be a central focus of ornithology, ecology and conservation efforts worldwide.