- Cabot's Tern
- Calandra Lark
- California Quail
- Campo Flicker
- Canada Goose
- Canary Flyrobin
- Cape Barren Goose
- Cape Batis
- Cape Bulbul
- Cape Bunting
- Cape Canary
- Cape Cormorant
- Cape Crow
- Cape Gannet
- Cape Grassbird
- Cape Longclaw
- Cape May Warbler
- Cape Penduline Tit
- Cape Petrel
- Cape Robin-Chat
- Cape Rock Thrush
- Cape Shoveler
- Cape Siskin
- Cape Sparrow
- Cape Spurfowl
- Cape Starling
- Cape Sugarbird
- Cape Teal
- Cape Vulture
- Cape Wagtail
- Cape Weaver
- Cape White-eye
- Capped Conebill
- Capped Heron
- Capped White-eye
- Carbonated Sierra Finch
- Cardinal Woodpecker
- Carib Grackle
- Caribbean Elaenia
- Caribbean Martin
- Carmelite Sunbird
- Carmiol's Tanager
- Carrion Crow
- Carruthers's Cisticola
- Carunculated Caracara
- Caspian Gull
- Caspian Plover
- Caspian Tern
- Cassin's Flycatcher
- Cassin's Honeybird
- Cattle Tyrant
- Cauca Guan
- Cave Swallow
- Celestial Monarch
- Central American Pygmy Owl
- Cerulean Cuckooshrike
- Cerulean Kingfisher
- Cetti's Warbler
- Chabert Vanga
- Chaco Chachalaca
- Chaco Earthcreeper
- Chaco Puffbird
- Chaco Sparrow
- Chalk-browed Mockingbird
- Channel-billed Cuckoo
- Charming Hummingbird
- Chatham Albatross
- Chattering Lory
- Checker-throated Stipplethroat
- Checkered Woodpecker
- Chestnut-and-black Weaver
- Chestnut-backed Antbird
- Chestnut-bellied Fantail
- Chestnut-bellied Guan
- Chestnut-bellied Nuthatch
- Chestnut-bellied Rock Thrush
- Chestnut-bellied Sandgrouse
- Chestnut-bellied Seedeater
- Chestnut-breasted Coronet
- Chestnut-breasted Cuckoo
- Chestnut-breasted Malkoha
- Chestnut-breasted Mannikin
- Chestnut-capped Babbler
- Chestnut-capped Brushfinch
- Chestnut-capped Warbler
- Chestnut-crowned Antpitta
- Chestnut-crowned Babbler
- Chestnut-crowned Warbler
- Chestnut-eared Aracari
- Chestnut-fronted Macaw
- Chestnut-headed Bee-eater
- Chestnut-headed Oropendola
- Chestnut-rumped Heathwren
- Chestnut-rumped Thornbill
- Chestnut-throated Apalis
- Chestnut-vented Warbler
- Chestnut Munia
- Chestnut Quail-thrush
- Chestnut Teal
- Chestnut Weaver
- Chiguanco Thrush
- Chilean Flamingo
- Chilean Flicker
- Chilean Swallow
- Chiloe Wigeon
- Chimango Caracara
- Chinese Pond Heron
- Chinese Sparrowhawk
- Chinspot Batis
- Chirruping Wedgebill
- Chivi Vireo
- Choco Manakin
- Choco Sirystes
- Chocolate-backed Kingfisher
- Chocolate-vented Tyrant
- Chocolate Boobook
- Chopi Blackbird
- Chorister Robin-Chat
- Chubb's Cisticola
- Chubut Steamer Duck
- Chukar Partridge
- Cinereous Conebill
- Cinereous Harrier
- Cinereous Vulture
- Cinnabar Boobook
- Cinnamon-bellied Imperial Pigeon
- Cinnamon-chested Bee-eater
- Cinnamon Becard
- Cinnamon Flycatcher
- Cinnamon Quail-thrush
- Cinnamon Woodpecker
- Cirl Bunting
- Citril Finch
- Citrine Canary-flycatcher
- Citrine Wagtail
- Citrine Warbler
- Clamorous Reed Warbler
- Clapperton's Spurfowl
- Claret-breasted Fruit Dove
- Clay-colored Thrush
- Cliff Flycatcher
- Cloud-forest Pygmy Owl
- Coal Tit
- Cocoa Woodcreeper
- Cocoi Heron
- Coconut Lorikeet
- Coleto
- Collared Aracari
- Collared Babbler
- Collared Flycatcher
- Collared Imperial Pigeon
- Collared Inca
- Collared Owlet
- Collared Pratincole
- Collared Sparrowhawk
- Collared Sunbird
- Collared Whitestart
- Colombian Chachalaca
- Comb-crested Jacana
- Common Babbler
- Common Black Hawk
- Common Blackbird
- Common Bronzewing
- Common Bulbul
- Common Buzzard
- Common Cactus Finch
- Common Chiffchaff
- Common Chlorospingus
- Common Cicadabird
- Common Crane
- Common Cuckoo
- Common Diving Petrel
- Common Eider
- Common Emerald Dove
- Common Firecrest
- Common Flameback
- Common Gallinule
- Common Goldeneye
- Common Grasshopper Warbler
- Common Green Magpie
- Common Greenshank
- Common Ground Dove
- Common Gull
- Common Hill Myna
- 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 Paradise Kingfisher
- Common Pheasant
- Common Pochard
- Common Potoo
- Common Redpoll
- Common Redshank
- Common Redstart
- Common Reed Bunting
- Common Reed Warbler
- Common Reed Warbler (baeticatus)
- Common Ringed Plover
- Common Rock Thrush
- Common Rosefinch
- Common Sandpiper
- Common Scimitarbill
- Common Scoter
- Common Shelduck
- Common Smoky Honeyeater
- Common Snipe
- Common Starling
- Common Swift
- Common Tailorbird
- Common Tern
- Common Tody-Flycatcher
- Common Waxbill
- Common Whitethroat
- Common Wood Pigeon
- Common Woodshrike
- Common Yellowthroat
- Compact Weaver
- Cook's Petrel
- Copper-tailed Starling
- Copper-throated Sunbird
- Copper Sunbird
- Copperback Quail-thrush
- Coppersmith Barbet
- Coquerel's Coua
- Cordilleran Canastero
- Cordoba Cinclodes
- Corn Bunting
- Correndera Pipit
- Corsican Finch
- Corsican Nuthatch
- Cory's Shearwater
- Coscoroba Swan
- Costa Rican Brushfinch
- Costa Rican Pygmy Owl
- Cotton Pygmy Goose
- Crab-plover
- Cream-colored Courser
- Cream-throated White-eye
- Creamy-bellied Thrush
- Crescent-caped Lophorina
- Crescent Honeyeater
- Crested Barbet
- Crested Bellbird
- Crested Black Tyrant
- Crested Bunting
- Crested Caracara
- Crested Coua
- Crested Drongo
- Crested Duck
- Crested Eagle
- Crested Francolin
- Crested Gallito
- Crested Guan
- Crested Honey Buzzard
- Crested Hornero
- Crested Lark
- Crested Oropendola
- Crested Quetzal
- Crested Satinbird
- Crested Serpent Eagle
- Crested Tit
- Crimson-backed Tanager
- Crimson-crested Woodpecker
- Crimson-mantled Woodpecker
- Crimson-naped Woodpecker
- Crimson-rumped Toucanet
- Crimson-rumped Waxbill
- Crimson-winged Woodpecker
- Crimson Finch
- Crimson Rosella
- Crimson Sunbird
- Crinkle-collared Manucode
- Croaking Cisticola
- Crowned Cormorant
- Crowned Eagle
- Crowned Hornbill
- Crowned Lapwing
- Crowned Slaty Flycatcher
- Crowned Woodnymph
- Cryptic Warbler
- Cuckoo-roller
- Curlew Sandpiper
- Curve-billed Reedhaunter