swainsoni

Swainsoni is a Latinized species epithet used in the scientific names of many organisms to honor the English naturalist William Swainson (1789–1855). In binomial nomenclature, swainsoni is a masculine form appended to a genus to form a species name; the epithet itself is not a standalone taxon. As a patronym, it recurs across diverse groups of organisms, including birds, reptiles, fishes, insects, and plants. Each use denotes separate, unrelated lineages.

A widely known example is Buteo swainsoni, the Swainson's hawk, a raptor of western North America that migrates to South America for the winter. Beyond this, the epithet appears in numerous other taxa, reflecting its role as a commemorative name rather than indicating shared biological characteristics among the species.

Because many species across different groups bear the epithet swainsoni, there is no single trait or region associated with the name. The use of swainsoni is primarily historical and commemorative. For a comprehensive list of species that adopt this epithet, taxonomic databases and references in ornithology, herpetology, botany, and other fields can be consulted.