- Caatinga Antwren
- Caatinga Cacholote
- Caatinga Puffbird
- Cabanis's Bunting
- Cackling Goose
- Cactus Wren
- Calandra Lark
- California Condor
- California Gnatcatcher
- California Gull
- California Quail
- California Scrub Jay
- California Thrasher
- California Towhee
- Cameroon Mountain Greenbul
- Cameroon Sunbird
- Campo Troupial
- Canada Goose
- Canada Jay
- Canary Flyrobin
- Canary Islands Chaffinch
- Canary Islands Chiffchaff
- Canary Islands Stonechat
- Canyon Towhee
- Canyon Wren
- Cape Barren Goose
- Cape Bulbul
- Cape Bunting
- Cape Cormorant
- Cape Crow
- Cape Eagle-Owl
- Cape Grassbird
- Cape Robin-Chat
- Cape Rockjumper
- Cape Sparrow
- Cape Spurfowl
- Cape Starling
- Cape Sugarbird
- Cape Teal
- Cape Vulture
- Cape Wagtail
- Capped Conebill
- Capped Heron
- Capped Wheatear
- Capped White-eye
- Cardinal Lory
- Cardinal Myzomela
- Cardinal Woodpecker
- Carmelite Sunbird
- Carp's Tit
- Carrion Crow
- Carruthers's Cisticola
- Caspian Plover
- Caspian Tern
- Cassin's Flycatcher
- Cassin's Hawk-Eagle
- Cassin's Honeybird
- Cassin's Kingbird
- Cassin's Malimbe
- Caucasian Grouse
- Cayenne Jay
- Ceara Gnateater
- Cedar Waxwing
- Cetti's Warbler
- Changeable Hawk-Eagle
- Channel-billed Cuckoo
- Chapada Flycatcher
- Chapman's Antshrike
- Chatham Islands Gerygone
- Chatham Islands Oystercatcher
- Chatham Islands Pigeon
- Chatham Islands Shag
- Chattering Cisticola
- Checker-throated Woodpecker
- Chestnut-backed Antshrike
- Chestnut-backed Chickadee
- Chestnut-backed Sparrow-Lark
- Chestnut-backed Thrush
- Chestnut-bellied Euphonia
- Chestnut-bellied Fantail
- Chestnut-bellied Flowerpiercer
- Chestnut-bellied Imperial Pigeon
- Chestnut-bellied Malkoha
- Chestnut-bellied Monarch
- Chestnut-bellied Nuthatch
- Chestnut-bellied Rock Thrush
- Chestnut-bellied Sandgrouse
- Chestnut-bellied Seed Finch
- Chestnut-bellied Seedeater
- Chestnut-bellied Starling
- Chestnut-bellied Tit
- Chestnut-belted Gnateater
- Chestnut-breasted Coronet
- Chestnut-breasted Cuckoo
- Chestnut-breasted Malkoha
- Chestnut-breasted Mannikin
- Chestnut-breasted Nigrita
- Chestnut-capped Babbler
- Chestnut-capped Blackbird
- Chestnut-capped Brushfinch
- Chestnut-capped Flycatcher
- Chestnut-capped Piha
- Chestnut-capped Puffbird
- Chestnut-cheeked Starling
- Chestnut-collared Swallow
- Chestnut-crowned Antpitta
- Chestnut-crowned Becard
- Chestnut-fronted Helmetshrike
- Chestnut-fronted Macaw
- Chestnut-headed Sparrow-Lark
- Chestnut-naped Spurfowl
- Chestnut-tailed Starling
- Chestnut-throated Apalis
- Chestnut-throated Flycatcher
- Chestnut-throated Seedeater
- Chestnut-tipped Toucanet
- Chestnut-vented Conebill
- Chestnut-vented Nuthatch
- Chestnut-vented Warbler
- Chestnut-winged Cinclodes
- Chestnut-winged Starling
- Chestnut Munia
- Chestnut Quail-thrush
- Chestnut Sparrow
- Chestnut Thrush
- Chestnut Wattle-eye
- Chestnut Weaver
- Chiguanco Thrush
- Chihuahuan Raven
- Chilean Flamingo
- Chiloe Wigeon
- Chimango Caracara
- Chinese Blue Flycatcher
- Chinese Egret
- Chinese Francolin
- Chinese Grouse
- Chinese Nuthatch
- Chinese Pond Heron
- Chinese Rubythroat
- Chinese Vivid Niltava
- Chinspot Batis
- Chipping Sparrow
- Chirruping Wedgebill
- Choco Brushfinch
- Choco Toucan
- Choco Tyrannulet
- Chocolate-backed Kingfisher
- Chubb's Cisticola
- Chubut Steamer Duck
- Chukar Partridge
- Cinereous Harrier
- Cinereous Mourner
- Cinereous Tit
- Cinereous Tit (minor)
- Cinereous Vulture
- Cinnamon-banded Kingfisher
- Cinnamon-bellied Ground Tyrant
- Cinnamon-breasted Bunting
- Cinnamon-browed Melidectes
- Cinnamon-chested Bee-eater
- Cinnamon-throated Woodcreeper
- Cinnamon-vented Piha
- Cinnamon Becard
- Cinnamon Bracken Warbler
- Cinnamon Flycatcher
- Cinnamon Teal
- Cinnamon Woodpecker
- Cirl Bunting
- Citril Finch
- Citrine Wagtail
- Clamorous Reed Warbler
- Clapperton's Spurfowl
- Claret-breasted Fruit Dove
- Clark's Grebe
- Clark's Nutcracker
- Clay-colored Sparrow
- Clay-colored Thrush
- Cliff Flycatcher
- Cloven-feathered Dove
- Club-winged Manakin
- Coal Tit
- Cobalt-rumped Parrotlet
- Cockatiel
- Cocoa Woodcreeper
- Cocoi Heron
- Coconut Lorikeet
- Collared Antshrike
- Collared Bush Robin
- Collared Crescentchest
- Collared Finchbill
- Collared Flycatcher
- Collared Inca
- Collared Kingfisher
- Collared Laughingthrush
- Collared Lory
- Collared Nightjar
- Collared Plover
- Collared Pratincole
- Collared Sparrowhawk
- Collared Sunbird
- Collared Trogon
- Colombian Chachalaca
- Comb-crested Jacana
- Comb Duck
- Common Babbler
- Common Black Hawk
- Common Blackbird
- Common Bronzewing
- Common Bulbul
- Common Buzzard
- Common Chiffchaff
- Common Chlorospingus
- Common Crane
- Common Cuckoo
- Common Diving Petrel
- Common Eider
- Common Emerald Dove
- Common Firecrest
- Common Gallinule
- Common Goldeneye
- Common Grasshopper Warbler
- Common Greenshank
- Common Ground Dove
- Common Hill Myna
- Common Iora
- Common Kestrel
- 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 Reed Warbler
- Common Ringed Plover
- Common Rock Thrush
- Common Rosefinch
- Common Sandpiper
- 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
- Cooper's Hawk
- Coopmans's Tyrannulet
- Copper Pheasant
- Copper Sunbird
- Coppersmith Barbet
- Coqui Francolin
- Corn Bunting
- Corn Crake
- Correndera Pipit
- Corsican Finch
- Corsican Nuthatch
- Cory's Shearwater
- Coscoroba Swan
- Costa's Hummingbird
- Crab-plover
- Cream-browed White-eye
- Cream-colored Courser
- Cream-colored Woodpecker
- Cream-vented Bulbul
- Creamy-bellied Thrush
- Creamy-crested Spinetail
- Creamy-rumped Miner
- Crescent-chested Puffbird
- Crested Auklet
- Crested Barbet
- Crested Becard
- Crested Bobwhite
- Crested Bunting
- Crested Caracara
- Crested Caracara (cheriway)
- Crested Cuckoo-Dove
- Crested Duck
- Crested Francolin
- Crested Goshawk
- Crested Honey Buzzard
- Crested Kingfisher
- Crested Lark
- Crested Malimbe
- Crested Oropendola
- Crested Pigeon
- Crested Serpent Eagle
- Crested Tit
- Crested Treeswift
- Crested White-eye
- Cretzschmar's Bunting
- Cricket Warbler
- Crimson-backed Tanager
- Crimson-breasted Finch
- Crimson-breasted Flowerpecker
- Crimson-breasted Shrike
- Crimson-browed Finch
- Crimson-hooded Manakin
- Crimson-mantled Woodpecker
- Crimson-naped Woodpecker
- Crimson-rumped Myzomela
- Crimson-rumped Toucanet
- Crimson-winged Woodpecker
- Crimson Rosella
- Crimson Shining Parrot
- Croaking Ground Dove
- Crow Honeyeater
- Crowned Cormorant
- Crowned Eagle
- Crowned Hornbill
- Crowned Lapwing
- Crowned Sandgrouse
- Crowned Slaty Flycatcher
- Crowned Woodnymph
- Cuban Gnatcatcher
- Cuban Pygmy Owl
- Cuban Tody
- Cuckoo-roller
- Curl-crested Aracari
- Curl-crested Manucode
- Curlew Sandpiper
- Curve-billed Thrasher
- Curve-billed Tinamou
- Cut-throat Finch
- Cyprus Warbler
- Cyprus Wheatear