- Cabot's Tern
- Calandra Lark
- California Gull
- Canada Goose
- Canada Jay
- Canary Islands Stonechat
- Canyon Wren
- Cape Bulbul
- Cape Bunting
- Cape Canary
- Cape Cormorant
- Cape Crow
- Cape Robin-Chat
- Cape Sparrow
- Cape Spurfowl
- Cape Starling
- Cape Teal
- Cape Wagtail
- Cape White-eye
- Capped Conebill
- Capped Heron
- Carib Grackle
- Carrion Crow
- Carruthers's Cisticola
- Carunculated Caracara
- Caspian Gull
- Caspian Tern
- Cassin's Finch
- Cetti's Warbler
- Chalk-browed Mockingbird
- Changeable Hawk-Eagle
- Channel-billed Toucan
- Charming Hummingbird
- Chat Flycatcher
- Checkered Woodpecker
- Chestnut-banded Plover
- Chestnut-bellied Sandgrouse
- Chestnut-bellied Seedeater
- Chestnut-bellied Starling
- Chestnut-breasted Coronet
- Chestnut-crowned Antpitta
- Chestnut-crowned Sparrow-Weaver
- Chestnut-eared Aracari
- Chestnut-fronted Macaw
- Chestnut-sided Warbler
- Chestnut-vented Warbler
- Chestnut-winged Cinclodes
- Chestnut-winged Foliage-gleaner
- Chestnut Sparrow
- Chiguanco Thrush
- Chilean Flamingo
- Chilean Flicker
- Chilean Swallow
- Chiloe Wigeon
- Chimango Caracara
- Chinspot Batis
- Chipping Sparrow
- Chiriqui Quail-Dove
- Choco Toucan
- Chubb's Cisticola
- Chukar Partridge
- Cinereous Conebill
- Cinereous Ground Tyrant
- Cinereous Harrier
- Cinereous Vulture
- Cinnamon-bellied Saltator
- Cinnamon-throated Woodcreeper
- Cinnamon Becard
- Cinnamon Flycatcher
- Cinnamon Hummingbird
- Cinnamon Teal
- Cinnamon Woodpecker
- Cirl Bunting
- Citril Finch
- Clamorous Reed Warbler
- Clark's Grebe
- Clay-colored Thrush
- Coal Tit
- Cobalt-winged Parakeet
- Cocoa Woodcreeper
- Cocoi Heron
- Collared Aracari
- Collared Inca
- Collared Plover
- Collared Pratincole
- Collared Sunbird
- Collared Trogon (aurantiiventris)
- Collared Whitestart
- Common Black Hawk
- Common Black Hawk (subtilis)
- Common Blackbird
- Common Bulbul
- Common Buzzard
- Common Chiffchaff
- Common Chlorospingus (ophthalmicus)
- Common Crane
- Common Cuckoo
- Common Eider
- Common Emerald Dove
- Common Firecrest
- Common Gallinule
- Common Goldeneye
- Common Greenshank
- Common Ground Dove
- Common Gull
- Common Hawk-Cuckoo
- Common Iora
- Common Kestrel
- Common Kingfisher
- Common Linnet
- Common Merganser
- Common Miner
- Common Moorhen
- Common Murre
- Common Myna
- Common Nightingale
- Common Ostrich
- Common Pheasant
- Common Pochard
- Common Potoo
- Common Redpoll
- Common Redshank
- Common Redstart
- Common Reed Bunting
- Common Reed Warbler
- Common Ringed Plover
- Common Rock Thrush
- 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
- Cooper's Hawk
- Copper Sunbird
- Coppersmith Barbet
- Coqui Francolin
- Cordilleran Canastero
- Corn Bunting
- Correndera Pipit
- Coscoroba Swan
- Cream-winged Cinclodes
- Creamy-bellied Thrush
- Creamy-crested Spinetail
- Crested Barbet
- Crested Caracara
- Crested Caracara (cheriway)
- Crested Duck
- Crested Francolin
- Crested Guan
- Crested Lark
- Crested Oropendola
- Crested Owl
- Crested Serpent Eagle
- Crested Tit
- Crimson-breasted Shrike
- Crimson-collared Tanager
- Crimson-fronted Barbet
- Crimson-mantled Woodpecker
- Crimson-rumped Toucanet
- Crimson-rumped Waxbill
- Croaking Cisticola
- Croaking Ground Dove
- Crowned Eagle
- Crowned Hornbill
- Crowned Lapwing
- Crowned Woodnymph (fannyae)
- Curlew Sandpiper
- Cut-throat Finch
- Cuzco Brushfinch