Overview — The bird order Apodiformes comprises two well known groups: the aerial swifts and the nectar‑feeding hummingbirds. Members of this order are true birds with extreme flight specializations and occupy many habitats worldwide. Together they include nearly 450 species, making Apodiformes one of the most species‑rich avian orders after the passerines.

Characteristics

Apodiformes share several distinctive features: long, narrow wings for sustained or rapid flight; small, weak feet adapted for clinging rather than walking; lightweight bodies; and high metabolic rates (especially in hummingbirds). Hummingbirds can hover and fly backwards using rapid wingbeats, while swifts are adapted to fast, efficient aerial pursuit of insects.

Taxonomy and evolution

The order traditionally includes the families Trochilidae (hummingbirds), Apodidae (true swifts) and Hemiprocnidae (tree‑swifts). Fossil and molecular studies place their origins in the Cenozoic era; hummingbirds diversified in the Americas, whereas swifts have a nearly global distribution.

Behavior and ecology

Feeding strategies differ markedly: hummingbirds feed mainly on nectar and small arthropods, serving as pollinators in many ecosystems, while swifts are aerial insectivores that catch prey in flight. Some swifts spend much of their lives airborne, feeding, sleeping and mating on the wing. Nesting varies from tiny cup nests built by hummingbirds to adhesive nests of certain swifts.

Importance and conservation

Apodiformes play key ecological roles—pollination by hummingbirds and insect control by swifts. Conservation concerns include habitat loss, climate change, and threats to migratory routes. Several species are monitored or protected, and research on their energetics and flight mechanics informs broader avian biology.

Notable facts

  • Hummingbirds include the smallest living bird species, noted for extreme hovering abilities.
  • Swifts are among the most aerial of birds; some species roost on vertical surfaces or in colonies.
  • Families and diversity are described in ornithological resources such as overview pages and field guides; taxonomic details continue to be refined.

For summaries, identification guidance and further study see general references and species lists available via trusted ornithological portals and databases (Apodiformes, bird resources and annotated species counts at global checklists).