- Calandra Lark
- California Gull
- California Scrub Jay
- California Towhee
- Canada Goose
- Canary Islands Chiffchaff
- Cape Crow
- Cape Eagle-Owl
- Cape May Warbler
- Cape Teal
- Capped Conebill
- Capped Wheatear
- Capuchinbird
- Cardinal Woodpecker
- Carib Grackle
- Carrion Crow
- Caspian Gull
- Caspian Tern
- Cassin's Flycatcher
- Cauca Guan
- Cedar Waxwing
- Cetti's Warbler
- Chabert Vanga
- Changeable Hawk-Eagle
- Chestnut-backed Sparrow-Lark
- Chestnut-bellied Sandgrouse
- Chestnut-breasted Malkoha
- Chestnut-capped Babbler
- Chestnut-crowned Antpitta
- Chestnut-fronted Macaw
- Chestnut-headed Bee-eater
- Chestnut-naped Antpitta
- Chestnut-naped Spurfowl
- Chestnut-sided Warbler
- Chestnut-tailed Starling
- Chestnut Munia
- Chestnut Sparrow
- Chestnut Teal
- Chinese Pond Heron
- Chipping Sparrow
- Chocolate-backed Kingfisher
- Chukar Partridge
- Cinereous Bunting
- Cinereous Vulture
- Cinnamon-breasted Bunting
- Cinnamon Flycatcher
- Cirl Bunting
- Citril Finch
- Citrine Wagtail
- Clark's Grebe
- Coal Tit
- Collared Aracari
- Collared Flycatcher
- Collared Inca
- Collared Kingfisher
- Collared Nightjar
- Collared Plover
- Collared Pratincole
- Collared Sunbird
- Collared Trogon
- Common Blackbird
- Common Bulbul
- Common Buzzard
- Common Chaffinch
- Common Chaffinch (spodiogenys)
- Common Chiffchaff
- Common Chiffchaff (tristis)
- Common Crane
- Common Cuckoo
- Common Eider
- Common Firecrest
- Common Flameback
- Common Gallinule
- Common Goldeneye
- Common Grackle
- Common Grasshopper Warbler
- Common Green Magpie
- Common Greenshank
- Common Ground Dove
- Common Gull
- Common Hawk-Cuckoo
- Common House Martin
- Common Iora
- Common Jery
- Common Kestrel
- Common Kingfisher
- Common Linnet
- Common Loon
- Common Merganser
- Common Moorhen
- Common Murre
- Common Myna
- Common Newtonia
- Common Nightingale
- Common Ostrich
- Common Pheasant
- Common Pochard
- Common Potoo
- Common Quail
- Common Redpoll
- Common Redshank
- Common Redshank (robusta)
- Common Redstart
- Common Reed Bunting
- Common Reed Warbler
- Common Ringed Plover
- Common Rock Thrush
- Common Rosefinch
- Common Sandpiper
- Common Scoter
- Common Shelduck
- Common Snipe
- Common Starling
- Common Swift
- Common Tailorbird
- Common Tern
- Common Tody-Flycatcher
- Common Waxbill
- Common Whitethroat
- Common Wood Pigeon
- Common Yellowthroat
- Copper-tailed Starling
- Coppersmith Barbet
- Coquerel's Coua
- Corn Bunting
- Corn Crake
- Corsican Finch
- Corsican Nuthatch
- Cory's Shearwater
- Cotton Pygmy Goose
- Crab-plover
- Cream-colored Courser
- Cream-colored Woodpecker
- Crested Caracara (cheriway)
- Crested Coua
- Crested Drongo
- Crested Francolin
- Crested Honey Buzzard
- Crested Lark
- Crested Oropendola
- Crested Pigeon
- Crested Serpent Eagle
- Crested Tit
- Crested Treeswift
- Cretzschmar's Bunting
- Cricket Warbler
- Crimson-backed Tanager
- Crimson-crested Woodpecker
- Crimson-hooded Manakin
- Crimson-mantled Woodpecker
- Crimson Sunbird
- Croaking Cisticola
- Crowned Hornbill
- Crowned Lapwing
- Crowned Sandgrouse
- Cuckoo-roller
- Curlew Sandpiper
- Cut-throat Finch
- Cyprus Wheatear