- Cabot's Tern (eurygnathus)
- Canada Goose
- Canary Islands Chiffchaff
- Canvasback
- Cape Barren Goose
- Cape May Warbler
- Carib Grackle
- Caribbean Coot
- Carrion Crow
- Caspian Gull
- Caspian Tern
- Cave Swiftlet
- Cetti's Warbler
- Chilean Flamingo
- Chiloe Wigeon
- Chinese Egret
- Chinese Pond Heron
- Cinnamon Becard
- Cirl Bunting
- Citrine Wagtail
- Cockatiel
- Cocoi Heron
- Coconut Lorikeet
- Collared Kingfisher
- Collared Plover
- Common Blackbird
- Common Bulbul
- Common Buzzard
- Common Chaffinch
- Common Chiffchaff
- Common Crane
- Common Cuckoo
- Common Eider
- Common Emerald Dove
- Common Firecrest
- Common Flameback
- Common Gallinule
- Common Goldeneye
- Common Greenshank
- Common Ground Dove
- Common Hill Myna
- Common House Martin
- Common Kestrel
- Common Kestrel (canariensis)
- Common Kingfisher
- Common Linnet
- Common Loon
- Common Merganser
- Common Moorhen
- Common Murre
- Common Myna
- Common Nightingale
- Common Ostrich
- Common Pheasant
- Common Pochard
- Common Quail
- Common Redshank
- Common Redstart
- Common Reed Bunting
- Common Ringed Plover
- Common Sandpiper
- Common Shelduck
- Common Snipe
- Common Starling
- Common Swift
- Common Tailorbird
- Common Tern
- Common Waxbill
- Common Wood Pigeon
- Coppersmith Barbet
- Corsican Finch
- Cory's Shearwater
- Cotton Pygmy Goose
- Crested Barbet
- Crested Guineafowl
- Crested Honey Buzzard
- Crested Lark
- Crested Pigeon
- Cuban Grassquit
- Curlew Sandpiper