- Cabot's Tern
- Cactus Wren
- California Gnatcatcher
- California Gull
- California Scrub Jay
- California Thrasher
- California Towhee
- Canada Goose
- Canada Warbler
- Canvasback
- Canyon Towhee
- Cape May Warbler
- Carolina Wren
- Caspian Tern
- Cassin's Kingbird
- Cedar Waxwing
- Cerulean Warbler
- Chihuahuan Raven
- Chipping Sparrow
- Cinnamon Teal
- Clay-colored Thrush
- Coastal Miner
- Collared Aracari
- Common Goldeneye
- Common Grackle
- Common Ground Dove
- Common Hill Myna
- Common Merganser
- Common Moorhen
- Common Myna
- Common Redpoll
- Common Starling
- Common Yellowthroat
- Cooper's Hawk
- Costa's Hummingbird
- Couch's Kingbird
- Crescent-chested Warbler
- Crested Caracara (cheriway)
- Crimson-backed Tanager
- Crimson-collared Grosbeak
- Crissal Thrasher
- Croaking Ground Dove
- Crowned Woodnymph
- Curve-billed Thrasher