- Caatinga Cacholote
- Caatinga Puffbird
- Cabanis's Tanager
- Calandra Lark
- Campo Flicker
- Canada Goose
- Canada Warbler
- Cape Petrel
- Capped Heron
- Carrion Crow
- Caspian Gull
- Caspian Tern
- Cattle Tyrant
- Cetti's Warbler
- Chaco Chachalaca
- Chalk-browed Mockingbird
- Charming Hummingbird
- Checkered Woodpecker
- Chestnut-backed Antbird
- Chestnut-backed Antshrike
- Chestnut-bellied Mountain Tanager
- Chestnut-bellied Seedeater
- Chestnut-breasted Coronet
- Chestnut-breasted Mountain Finch
- Chestnut-capped Brushfinch
- Chestnut-capped Puffbird
- Chestnut-collared Swift
- Chestnut-colored Woodpecker
- Chestnut-crested Cotinga
- Chestnut-crowned Antpitta
- Chestnut-eared Aracari
- Chestnut-fronted Macaw
- Chestnut-sided Warbler
- Chestnut-throated Seedeater
- Chiguanco Thrush
- Chilean Flamingo
- Chilean Skua
- Choco Toucan
- Choco Trogon
- Choco Warbler
- Chopi Blackbird
- Chotoy Spinetail
- Chukar Partridge
- Cinereous Bunting
- Cinereous Conebill
- Cinereous Harrier
- Cinereous Tyrant
- Cinereous Vulture
- Cinnamon-bellied Flowerpiercer
- Cinnamon-rumped Seedeater
- Cinnamon-throated Woodcreeper
- Cinnamon Attila
- Cinnamon Becard
- Cinnamon Flycatcher
- Cinnamon Hummingbird
- Cinnamon Teal
- Cinnamon Woodpecker
- Cirl Bunting
- Citril Finch
- Citrine Wagtail
- Citrine Warbler
- Clay-colored Thrush
- Cliff Flycatcher
- Club-winged Manakin
- Coal Tit
- Coastal Miner
- Cocha Antshrike
- Cocoi Heron
- Collared Antshrike
- Collared Aracari
- Collared Flycatcher
- Collared Inca
- Collared Plover
- Collared Pratincole
- Collared Trogon
- Collared Warbling Finch
- Collared Whitestart
- Common Black Hawk
- Common Black Hawk (subtilis)
- Common Blackbird
- Common Bush Tanager (ophthalmicus)
- Common Buzzard
- Common Chaffinch
- Common Chiffchaff
- Common Crane
- Common Cuckoo
- Common Eider
- Common Firecrest
- Common Goldeneye
- Common Grasshopper Warbler
- Common Greenshank
- Common House Martin
- Common Kestrel
- Common Kingfisher
- Common Linnet
- Common Loon
- Common Merganser
- Common Moorhen
- Common Murre
- Common Nightingale
- Common Pheasant
- Common Pochard
- Common Potoo
- Common Quail
- Common Redpoll
- Common Redshank
- Common Redstart
- Common Reed Bunting
- Common Ringed Plover
- Common Rosefinch
- Common Sandpiper
- Common Scoter
- Common Shelduck
- Common Snipe
- Common Starling
- Common Swift
- Common Tern
- Common Tody-Flycatcher
- Common Waxbill
- Common Whitethroat
- Common Wood Pigeon
- Common Yellowthroat
- Coppery-headed Emerald
- Coppery Metaltail
- Cordilleran Canastero
- Corn Bunting
- Correndera Pipit
- Cory's Shearwater
- Costa Rican Swift
- Cream-colored Woodpecker
- Cream-winged Cinclodes
- Creamy-bellied Thrush
- Creamy-crested Spinetail
- Crested Duck
- Crested Lark
- Crested Oropendola
- Crested Quetzal
- Cretzschmar's Bunting
- Crimson-backed Tanager
- Crimson-crested Woodpecker
- Crimson-mantled Woodpecker
- Crimson-rumped Toucanet
- Croaking Ground Dove
- Crowned Slaty Flycatcher
- Crowned Woodnymph
- Crowned Woodnymph (fannyae)
- Curl-crested Aracari
- Curlew Sandpiper