- Cabot's Tragopan
- Cachar Wedge-billed Babbler
- Calandra Lark
- California Quail
- Calliope Hummingbird
- Canivet's Emerald
- Cape Barren Goose
- Cape Petrel
- Carrion Crow
- Caspian Snowcock
- Caspian Tern
- Caucasian Grouse
- Cerulean Cuckooshrike
- Cetti's Warbler
- Channel-billed Cuckoo
- Channel-billed Toucan
- Channel-billed Toucan (ariel)
- Channel-billed Toucan (culminatus)
- Chattering Lory
- Cheer Pheasant
- Chestnut-bellied Monarch
- Chestnut-bellied Rock Thrush
- Chestnut-bellied Sandgrouse
- Chestnut-crowned Babbler
- Chestnut-eared Aracari
- Chestnut-eared Bunting
- Chestnut-headed Tesia
- Chestnut-tipped Toucanet
- Chestnut-vented Nuthatch
- Chestnut Quail-thrush
- Chestnut Rail
- Chestnut Teal
- Chestnut Thrush
- Chinese Bamboo Partridge
- Chinese Grosbeak
- Choco Toucan
- Chowchilla
- Cinereous Harrier
- Cinereous Vulture
- Cinnamon-browed Melidectes
- Cinnamon-rumped Trogon
- Cinnamon Hummingbird
- Cirl Bunting
- Citreoline Trogon
- Citril Finch
- Citron-throated Toucan
- Coal Tit
- Coal Tit (melanolophus)
- Cockatiel
- Cockerell's Fantail
- Collared Aracari
- Collared Finchbill
- Collared Flycatcher
- Collared Grosbeak
- Collared Inca
- Collared Owlet
- Collared Pratincole
- Collared Sparrowhawk
- Collared Trogon
- Collared Trogon (aurantiiventris)
- Comb-crested Jacana
- Common Blackbird
- Common Bronzewing
- Common Buttonquail
- Common Buzzard
- Common Chaffinch
- Common Chiffchaff (tristis)
- Common Cicadabird
- Common Crane
- Common Cuckoo
- Common Eider
- Common Firecrest
- Common Flameback
- Common Goldeneye
- Common Green Magpie
- Common Greenshank
- Common Gull
- Common House Martin
- Common Kestrel
- Common Kingfisher
- Common Linnet
- Common Loon
- Common Merganser
- Common Moorhen
- Common Murre
- Common Nightingale
- Common Pheasant
- Common Pochard
- Common Quail
- Common Redshank
- Common Redstart
- Common Reed Bunting
- Common Reed Warbler
- Common Ringed Plover
- Common Rock Thrush
- Common Rosefinch
- Common Scoter
- Common Shelduck
- Common Snipe
- Common Starling
- Common Swift
- Common Tern
- Common Whitethroat
- Common Wood Pigeon
- Cook's Petrel
- Copper Pheasant
- Corn Bunting
- Corn Crake
- Costa's Hummingbird
- Cotton Pygmy Goose
- Cream-colored Courser
- Cream-throated White-eye
- Crested Bobwhite
- Crested Finchbill
- Crested Lark
- Crested Pigeon
- Crested Quetzal
- Crested Tit
- Crested Treeswift
- Crimson-headed Partridge
- Crimson-rumped Toucanet
- Crimson Rosella
- Crimson Rosella (flaveolus)
- Crimson Sunbird
- Crowned Sandgrouse
- Cuban Emerald
- Curl-crested Aracari
- Curlew Sandpiper