- Cabot's Tern (eurygnathus)
- Caica Parrot
- California Gull
- California Quail
- California Scrub Jay
- Canada Goose
- Canada Jay
- Canary Islands Chiffchaff
- Canvasback
- Cape Barren Goose
- Cape Petrel
- Cape Robin-Chat
- Cape Teal
- Capped Wheatear
- Carib Grackle
- Carnaby's Black Cockatoo
- Carrion Crow
- Caspian Tern
- Casqued Oropendola
- Cassin's Finch
- Cedar Waxwing
- Chabert Vanga
- Channel-billed Toucan
- Chestnut-backed Chickadee
- Chestnut-bellied Seed Finch
- Chestnut-bellied Seedeater
- Chestnut-breasted Mannikin
- Chestnut-eared Aracari
- Chestnut-headed Bee-eater
- Chestnut-quilled Rock Pigeon
- Chestnut-rumped Woodcreeper
- Chestnut Teal
- Chiguanco Thrush
- Cinereous Antshrike
- Cinereous Becard
- Cinereous Vulture
- Cinnamon-chested Bee-eater
- Cinnamon Attila
- Cinnamon Quail-thrush
- Cinnamon Teal
- Clamorous Reed Warbler
- Clark's Grebe
- Clark's Nutcracker
- Cockatiel
- Cocoi Heron
- Coconut Lorikeet
- Collared Forest Falcon
- Collared Kingfisher
- Collared Plover
- Collared Puffbird
- Collared Sparrowhawk
- Collared Trogon
- Comb-crested Jacana
- Common Blackbird
- Common Bronzewing
- Common Chaffinch
- Common Eider
- Common Emerald Dove
- Common Grackle
- Common Greenshank
- Common Ground Dove
- Common Hill Myna
- Common House Martin
- Common Jery
- Common Loon
- Common Merganser
- Common Miner
- Common Moorhen
- Common Myna
- Common Newtonia
- Common Nighthawk
- Common Ostrich
- Common Potoo
- Common Redshank
- Common Sandpiper
- Common Scale-backed Antbird
- Common Shelduck
- Common Snipe
- Common Starling
- Common Tern
- Common Tody-Flycatcher
- Common Waxbill
- Common Wood Pigeon
- Comoros Blue Pigeon
- Copper-rumped Hummingbird
- Coquerel's Coua
- Coqui Francolin
- Coraya Wren
- Corn Bunting
- Crab-plover
- Crane Hawk
- Cream-colored Woodpecker
- Cream-winged Cinclodes
- Crescent Honeyeater
- Crested Bellbird
- Crested Caracara
- Crested Coua
- Crested Drongo
- Crested Duck
- Crested Francolin
- Crested Oropendola
- Crested Pigeon
- Crested Serpent Eagle
- Crimson-crested Woodpecker
- Crimson-hooded Manakin
- Crimson Finch
- Crimson Rosella
- Crimson Topaz
- Crowned Hornbill
- Crowned Lapwing
- Cuckoo Roller
- Curlew Sandpiper