No caeca. Oil-gland present, but nude. Palate aegithognathous; no basipterygoid processes. No median wing-coverts. Sternum without posterior incisions, the keel high. No semitendinosus muscle. A large aftershaft.
Nidification varies greatly, but all the Swifts lay elongate white eggs, and in all the saliva is used to cement together the materials of the nest and to attach it to some surface. In some forms of Collocalia the nest consists entirely of inspissated saliva. The salivary glands are greatly developed, especially at the breeding-season. The young are hatched naked.
A single family.