- Cabanis's Bunting
- Cabanis's Greenbul
- Cabanis's Wren
- Cachar Wedge-billed Babbler
- Cackling Goose
- Calandra Lark
- Campbell Albatross
- Campo Flicker
- Campo Troupial
- Canada Goose
- Canada Warbler
- Canary Flyrobin
- Canary Islands Chaffinch
- Canary Islands Chiffchaff
- Canary Islands Stonechat
- Canary White-eye
- Canivet's Emerald
- Canyon Wren
- Cape Barren Goose
- Cape Batis
- Cape Bulbul
- Cape Bunting
- Cape Canary
- Cape Clapper Lark
- Cape Cormorant
- Cape Crow
- Cape Eagle-Owl
- Cape Gannet
- Cape Grassbird
- Cape Long-billed Lark
- Cape Longclaw
- Cape May Warbler
- Cape Parrot
- 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 Heron
- Capped Wheatear
- Capped White-eye
- Cardinal Lory
- Cardinal Myzomela
- Cardinal Woodpecker
- Carib Grackle
- Caribbean Dove
- Caribbean Hornero
- Carmelite Sunbird
- Carmiol's Tanager
- Carp's Tit
- Carrion Crow
- Carruthers's Cisticola
- Carunculated Caracara
- Caspian Gull
- Caspian Tern
- Cassin's Finch
- Cassin's Flycatcher
- Cassin's Kingbird
- Cattle Tyrant
- Cave Swallow
- Cave Swiftlet
- Cerulean-capped Manakin
- Cerulean Kingfisher
- Cerulean Warbler
- Cetti's Warbler
- Chabert Vanga
- Chaco Chachalaca
- Chaco Earthcreeper
- Chaco Owl
- Chaco Puffbird
- Chalk-browed Mockingbird
- Changeable Hawk-Eagle
- Channel-billed Cuckoo
- Channel-billed Toucan
- Chapin's Apalis
- Charlotte's Bulbul
- Chat Flycatcher
- Chattering Cisticola
- Chattering Lory
- Checker-throated Woodpecker
- Checkered Woodpecker
- Chestnut-and-black Weaver
- Chestnut-backed Antbird
- Chestnut-backed Antshrike
- Chestnut-backed Owlet
- Chestnut-backed Sparrow-Lark
- Chestnut-backed Thrush
- Chestnut-banded Plover
- Chestnut-bellied Cuckoo
- Chestnut-bellied Euphonia
- Chestnut-bellied Imperial Pigeon
- Chestnut-bellied Monarch
- Chestnut-bellied Mountain Tanager
- Chestnut-bellied Nuthatch
- Chestnut-bellied Rock Thrush
- Chestnut-bellied Sandgrouse
- Chestnut-bellied Seed Finch
- Chestnut-bellied Seedeater
- Chestnut-bellied Starling
- Chestnut-bellied Thrush
- Chestnut-breasted Coronet
- Chestnut-breasted Malkoha
- Chestnut-breasted Mannikin
- Chestnut-breasted Nigrita
- Chestnut-capped Babbler
- Chestnut-capped Blackbird
- Chestnut-capped Brushfinch
- Chestnut-capped Flycatcher
- Chestnut-capped Thrush
- Chestnut-capped Warbler
- Chestnut-collared Longspur
- Chestnut-colored Woodpecker
- Chestnut-crested Yuhina
- Chestnut-crowned Antpitta
- Chestnut-crowned Becard
- Chestnut-crowned Laughingthrush
- Chestnut-crowned Sparrow-Weaver
- Chestnut-crowned Warbler
- Chestnut-eared Aracari
- Chestnut-faced Babbler
- Chestnut-fronted Helmetshrike
- Chestnut-fronted Macaw
- Chestnut-headed Bee-eater
- Chestnut-headed Oropendola
- Chestnut-headed Sparrow-Lark
- Chestnut-headed Tanager
- Chestnut-headed Tesia
- Chestnut-hooded Laughingthrush
- Chestnut-naped Forktail
- Chestnut-naped Spurfowl
- Chestnut-rumped Babbler
- Chestnut-rumped Heathwren
- Chestnut-rumped Thornbill
- Chestnut-sided Warbler
- Chestnut-tailed Starling
- Chestnut-throated Apalis
- Chestnut-throated Monal-Partridge
- Chestnut-throated Seedeater
- Chestnut-vented Conebill
- Chestnut-vented Nuthatch
- Chestnut-vented Warbler
- Chestnut-winged Babbler
- Chestnut-winged Chachalaca
- Chestnut-winged Cinclodes
- Chestnut-winged Starling
- Chestnut Munia
- Chestnut Piculet
- Chestnut Quail-thrush
- Chestnut Sparrow
- Chestnut Teal
- Chestnut Thrush
- Chestnut Wattle-eye
- Chestnut Weaver
- Chestnut Wood Quail
- Chiguanco Thrush
- Chilean Flamingo
- Chimango Caracara
- Chinese Babax
- Chinese Bamboo Partridge
- Chinese Blackbird
- Chinese Blue Flycatcher
- Chinese Egret
- Chinese Grosbeak
- Chinese Leaf Warbler
- Chinese Pond Heron
- Chinese Rubythroat
- Chinese White-browed Rosefinch
- Chinspot Batis
- Chinstrap Penguin
- Chiriqui Foliage-gleaner
- Chirping Cisticola
- Chirruping Nightjar
- Chivi Vireo
- Choco Black-throated Trogon
- Choco Brushfinch
- Choco Poorwill
- Choco Screech Owl
- Choco Toucan
- Choco Trogon
- Choco Warbler
- Chocolate-backed Kingfisher
- Chocolate Boobook
- Chopi Blackbird
- Chorister Robin-Chat
- Chotoy Spinetail
- Chowchilla
- Chubb's Cisticola
- Chuck-will's-widow
- Chukar Partridge
- Churring Cisticola
- Cinereous Antshrike
- Cinereous Bulbul
- Cinereous Conebill
- Cinereous Finch
- Cinereous Mourner
- Cinereous Tinamou
- Cinereous Tit
- Cinereous Tit (minor)
- Cinereous Tyrant
- Cinereous Vulture
- Cinnamon-banded Kingfisher
- Cinnamon-bellied Flowerpiercer
- Cinnamon-bellied Imperial Pigeon
- Cinnamon-bellied Saltator
- Cinnamon-breasted Bunting
- Cinnamon-breasted Tit
- Cinnamon-breasted Warbler
- Cinnamon-browed Melidectes
- Cinnamon-chested Bee-eater
- Cinnamon-rumped Foliage-gleaner
- Cinnamon-tailed Sparrow
- Cinnamon-throated Woodcreeper
- Cinnamon Attila
- Cinnamon Becard
- Cinnamon Bittern
- Cinnamon Bracken Warbler
- Cinnamon Flycatcher
- Cinnamon Hummingbird
- Cinnamon Ibon
- Cinnamon Screech Owl
- Cinnamon Tanager
- Cinnamon Teal
- Cinnamon Woodpecker
- Cirl Bunting
- Citreoline Trogon
- Citrine Canary-flycatcher
- Citrine Wagtail
- Citrine Warbler
- Citron-bellied Attila
- Citron-headed Yellow Finch
- Clamorous Reed Warbler
- Clapperton's Spurfowl
- Claret-breasted Fruit Dove
- Clark's Grebe
- Clark's Nutcracker
- Claudia's Leaf Warbler
- Clay-colored Sparrow
- Clay-colored Thrush
- Cliff Flycatcher
- Cloud Cisticola
- Coal Tit
- Coastal Cisticola
- Coastal Miner
- Cobalt-rumped Parrotlet
- Cobalt-winged Parakeet
- Cocha Antshrike
- Cock-tailed Tyrant
- Cockatiel
- Cocoa Woodcreeper
- Cocoi Heron
- Coconut Lorikeet
- Coleto
- Colima Pygmy Owl
- Collared Aracari
- Collared Crescentchest
- Collared Finchbill
- Collared Forest Falcon
- Collared Grosbeak
- Collared Inca
- Collared Kingfisher
- Collared Nightjar
- Collared Owlet
- Collared Palm Thrush
- Collared Plover
- Collared Pratincole
- Collared Sparrowhawk
- Collared Sunbird
- Collared Towhee
- Collared Treepie
- Collared Trogon
- Collared Warbling Finch
- 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 Crane
- Common Cuckoo
- Common Diving Petrel
- Common Eider
- Common Emerald Dove
- Common Flameback
- Common Gallinule
- Common Goldeneye
- Common Grackle
- Common Green Magpie
- Common Greenshank
- Common Ground Dove
- Common Gull
- Common Hawk-Cuckoo
- Common Hill Myna
- Common Iora
- Common Jery
- Common Kestrel
- Common Kingfisher
- Common Linnet
- Common Merganser
- Common Miner
- Common Moorhen
- Common Murre
- Common Myna
- Common Newtonia
- Common Nightingale
- Common Ostrich
- Common Paradise Kingfisher
- Common Pheasant
- Common Pochard
- Common Potoo
- Common Quail
- 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 Scale-backed Antbird
- Common Scimitarbill
- Common Shelduck
- Common Smoky Honeyeater
- Common Snipe
- Common Starling
- Common Sunbird-Asity
- Common Swift
- Common Tailorbird
- Common Tern
- Common Tody-Flycatcher
- Common Waxbill
- Common Whitethroat
- Common Wood Pigeon
- Common Woodshrike
- Common Yellowthroat
- Comoro Black Parrot
- Comoro Blue Pigeon
- Comoro Blue Vanga
- Comoro Cuckooshrike
- Comoro Fody
- Comoro Green Pigeon
- Comoro Olive Pigeon
- Comoro Thrush
- Compact Weaver
- Congo Moor Chat
- Congo Pied Hornbill
- Cook's Petrel
- Coopmans's Tyrannulet
- Copper-tailed Starling
- Copper-throated Sunbird
- Copper Sunbird
- Coppersmith Barbet
- Coppery-chested Jacamar
- Coppery-headed Emerald
- Coppery-tailed Coucal
- Coppery Metaltail
- Coquerel's Coua
- Coqui Francolin
- Coraya Wren
- Cordilleran Canastero
- Corn Bunting
- Corn Crake
- Cory's Shearwater
- Coscoroba Swan
- Cotton Pygmy Goose
- Couch's Kingbird
- Crab-plover
- Crane Hawk
- Cream-backed Woodpecker
- Cream-browed White-eye
- Cream-colored Courser
- Cream-colored Woodpecker
- Cream-eyed Bulbul
- Cream-throated White-eye
- Cream-vented Bulbul
- Cream-winged Cinclodes
- Creamy-bellied Antwren
- Creamy-bellied Thrush
- Creamy-crested Spinetail
- Crescent-chested Babbler
- Crescent-chested Puffbird
- Crescent-chested Warbler
- Crescent-faced Antpitta
- Crescent Honeyeater
- Crested Ant Tanager
- Crested Barbet
- Crested Becard
- Crested Bellbird
- Crested Bobwhite
- Crested Bunting
- Crested Caracara
- Crested Caracara (cheriway)
- Crested Coua
- Crested Drongo
- Crested Duck
- Crested Finchbill
- Crested Francolin
- Crested Gallito
- Crested Goshawk
- Crested Guan
- Crested Honey Buzzard
- Crested Hornero
- Crested Jayshrike
- Crested Kingfisher
- Crested Lark
- Crested Malimbe
- Crested Myna
- Crested Oropendola
- Crested Partridge
- Crested Pigeon
- Crested Quail-Dove
- Crested Quetzal
- Crested Serpent Eagle
- Crested Tit
- Crested Treeswift
- Crested White-eye
- Cretzschmar's Bunting
- Cricket Warbler
- Crimson-backed Flameback
- Crimson-backed Sunbird
- Crimson-backed Tanager
- Crimson-breasted Finch
- Crimson-breasted Flowerpecker
- Crimson-breasted Shrike
- Crimson-browed Finch
- Crimson-collared Tanager
- Crimson-crested Woodpecker
- Crimson-fronted Barbet
- Crimson-headed Partridge
- Crimson-hooded Manakin
- Crimson-mantled Woodpecker
- Crimson-naped Woodpecker
- Crimson-rumped Myzomela
- Crimson-rumped Toucanet
- Crimson-rumped Waxbill
- Crimson-winged Woodpecker
- Crimson Finch
- Crimson Rosella
- Crimson Sunbird
- Croaking Cisticola
- Croaking Ground Dove
- Crocker Jungle Flycatcher
- Crossley's Vanga
- Crow-billed Drongo
- Crowned Cormorant
- Crowned Eagle
- Crowned Hornbill
- Crowned Lapwing
- Crowned Sandgrouse
- Crowned Woodnymph
- Cryptic Becard
- Cryptic Warbler
- Cuckoo-roller
- Curl-crested Jay
- Curlew Sandpiper
- Curve-billed Thrasher
- Cut-throat Finch
- Cuzco Warbler
- Cyprus Scops Owl
- Cyprus Warbler
- Cyprus Wheatear