Many common English-language bird names consist of nouns or of adjectives followed by generic terms, such as eagle and sparrow. The editorial guidelines of organizations dedicated to birds, such as the American Ornithological Society (AOS) and the National Audubon Society, typically require capitalizing all terms in common bird names. In writing intended for nonspecialist audiences, however, capitalizing proper nouns and adjectives while lowercasing generic terms in common bird names may be appropriate.
Common bird names often include a place-name, as in these references to a geographical location within a species’ natural range:
American coot
Carolina chickadee
Canada goose
Some common bird names are eponymous (that is, named for a person), comprising a person’s name and a generic term:
Steller’s jay
Bonaparte’s gull
Cooper’s hawk
Many common bird names comprise only generic terms, even if the terms may not be common parlance:
surf scoter
prothonotary warbler
pied-billed grebe
Do not capitalize cardinal directions within common bird names:
northern cardinal
eastern bluebird
western barn owl
Please note that certain birds’ English-language common names may change; the AOS, which maintains the “Checklist of North and Middle American Birds,” has committed to changing the English-language common bird names of species under its purview that are eponymous, offensive, or exclusionary (“AOS Pilot Project”).
Consult a dictionary like Merriam-Webster when you’re uncertain whether terms in bird names are generic terms, proper nouns, or proper adjectives.
Works Cited
“AOS Pilot Project to Change Harmful English Common Bird Names.” American Ornithological Society, 13 May 2024, americanornithology.org/english-bird-names/aos-pilot-project-to-change-harmful-english-common-bird-names/.
“Checklist of North and Middle American Birds.” American Ornithological Society, checklist.americanornithology.org/taxa/. Accessed 22 Dec. 2025.