- Coccyzus pluvialis
- Coccyzus pumilus
- Coccyzus rufigularis
- Coccyzus vetula
- Coccyzus vieilloti
- Cocha Antshrike
- Cochabamba Mountain-Finch
- Cochabamba Mountain Finch
- Cochlearius
- Cochlearius cochlearia
- Cochlearius cochlearius
- Cochlearius cochlearius cochlearius
- Cochoa
- Cochoa azurea
- Cochoa beccarii
- Cochoa purpurea
- Cochoa viridis
- Cock-of-the-Rock Lodge
- Cock-tailed Tyrant
- Cockatiel
- Cockerell's Fantail
- Cocoa Thrush
- Cocoa Woodcreeper
- Cocoi Heron
- Coconut Lorikeet
- Cocos Cuckoo
- Cocos Finch
- Cocos Flycatcher
- Cocos Island Finch
- Cocos Island Flycatcher
- Coe's Honeyguide
- Coed Cefn Wood,Crickhowell
- Coed Garth Gell
- Coed Garth Gell RSPB Reserve Wales
- Coeligena
- Coeligena bonapartei
- Coeligena coeligena
- Coeligena eos
- Coeligena helianthea
- Coeligena inca
- Coeligena iris
- Coeligena lutetiae
- Coeligena orina
- Coeligena phalerata
- Coeligena prunellei
- Coeligena torquata
- Coeligena violifer
- Coeligena wilsoni
- Coenocorypha
- Coenocorypha aucklandica
- Coenocorypha barrierensis
- Coenocorypha chathamica
- Coenocorypha huegeli
- Coenocorypha iredalei
- Coenocorypha pusilla
- Coereba
- Coereba flaveola
- Coereba flaveola bananivora
- Coereba flaveola luteola
- Coerebidae
- Coiba Spinetail
- Col de Sorba
- Colaptes
- Colaptes aeruginosus
- Colaptes atricollis
- Colaptes auratus
- Colaptes auratus cafer
- Colaptes auricularis
- Colaptes campestris
- Colaptes campestris campestris
- Colaptes campestris campestroides
- Colaptes chrysoides
- Colaptes fernandinae
- Colaptes melanochloros
- Colaptes melanochloros melanochloros
- Colaptes melanolaimus
- Colaptes pitius
- Colaptes punctigula
- Colaptes punctigula punctipectus
- Colaptes rivolii
- Colaptes rubiginosus
- Colaptes rubiginosus coloratus
- Colaptes rubiginosus rubripileus
- Colaptes rupicola
- Colasisi
- Coldingham Bay
- Coleto
- Colibri
- Colibri coruscans
- Colibri cyanotus
- Colibri delphinae
- Colibri serrirostris
- Colibri thalassinus
- Coliidae
- Coliiformes
- Colima
- Colima Pygmy-Owl
- Colima Pygmy Owl
- Colima Warbler
- Colinus
- Colinus cristatus
- Colinus leucopogon
- Colinus nigrogularis
- Colinus virginianus
- Colinus virginianus texanus
- Colius
- Colius Striatus
- Colius castanotus
- Colius colius
- Colius leucocephalus
- Colius striatus
- Colius striatus striatus
- Coll
- Collacidia dodgei
- Collared Antshrike
- Collared Apalis
- Collared Aracari
- Collared Babbler
- Collared Broadbill
- Collared Brushturkey
- Collared Bush-Robin
- Collared Bush Chat
- Collared Bush Robin
- Collared Butcherbird
- Collared Crescent-chest
- Collared Crescentchest
- Collared Crow
- Collared Crow-Shrike
- Collared Falconet
- Collared Finchbill
- Collared Flycatcher
- Collared Forest-Falcon
- Collared Forest Falcon
- Collared Gnatwren
- Collared Grosbeak
- Collared Imperial-Pigeon
- Collared Imperial Pigeon
- Collared Inca
- Collared Jackdaw
- Collared Jay
- Collared Kingfisher
- Collared Lark
- Collared Laughingthrush
- Collared Lory
- Collared Myna
- Collared Mynah
- Collared Nightjar
- Collared Owlet
- Collared Palm-Thrush
- Collared Palm Thrush
- Collared Petrel
- Collared Plover
- Collared Pratincole
- Collared Puffbird
- Collared Redstart
- Collared Sand Martin
- Collared Scops-Owl
- Collared Scops Owl
- Collared Sparrowhawk
- Collared Sunbird
- Collared Towhee
- Collared Treepie
- Collared Trogon
- Collared Warbling-Finch
- Collared Warbling Finch
- Collared Whitestart
- Collared Yuhina
- Collocalia
- Collocalia affinis
- Collocalia affinis cyanoptila
- Collocalia brevirostris
- Collocalia dodgei
- Collocalia esculenta
- Collocalia isonota
- Collocalia linchi
- Collocalia marginata
- Collocalia natalis
- Collocalia neglecta
- Collocalia sumbawae
- Collocalia troglodytes
- Collocalia uropygialis
- Colluricincla
- Colluricincla boweri
- Colluricincla ferruginea
- Colluricincla harmonica
- Colluricincla incerta
- Colluricincla megarhyncha
- Colluricincla megarhyncha rufigaster
- Colluricincla sanghirensis
- Colluricincla tenebrosa
- Colluricincla umbrina
- Colluricincla woodwardi
- Coloeus
- Coloeus dauuricus
- Coloeus monedula
- Colombia
- Colombian Antwren
- Colombian Brush-Finch
- Colombian Brush Finch
- Colombian Chachalaca
- Colombian Crake
- Colombian Grebe
- Colombian Metaltail
- Colombian Mountain Grackle
- Colombian Screech-Owl
- Colombian Screech Owl
- Colombo Crow
- Colonia
- Colonia colonus
- Colonial Starling
- Colonist Kingfisher
- Colorado
- Colorful Puffleg
- Colorhamphus
- Colorhamphus parvirostris
- Colotis amata
- Colton Point State Park
- Colton Point State Park, Pine Creek Gorge(North Central PA, near Ansonia)
- Columba
- Columba albinucha
- Columba albitorques
- Columba araucana
- Columba argentina
- Columba arquatrix
- Columba bollii
- Columba caribaea
- Columba cayennensis
- Columba corensis
- Columba delegorguei
- Columba elphinstonii
- Columba eversmanni
- Columba fasciata
- Columba flavirostris
- Columba goodsoni
- Columba guinea
- Columba guinea guinea
- Columba hodgsonii
- Columba inornata
- Columba iriditorques
- Columba janthina
- Columba janthina janthina
- Columba jouyi
- Columba junoniae
- Columba larvata
- Columba leucocephala
- Columba leucomela
- Columba leuconota
- Columba livia
- Columba livia domestica
- Columba maculosa
- Columba malherbii
- Columba mayeri
- Columba nigrirostris
- Columba oenas
- Columba oenops
- Columba oliviae
- Columba pallidiceps
- Columba palumboides
- Columba palumbus
- Columba palumbus iranica
- Columba palumbus palumbus
- Columba picazuro
- Columba plumbea
- Columba pollenii
- Columba pulchricollis
- Columba punicea
- Columba rupestris
- Columba simplex
- Columba sjostedti
- Columba speciosa
- Columba squamosa
- Columba subvinacea
- Columba thomensis
- Columba torringtoni
- Columba torringtoniae
- Columba trocaz
- Columba unicincta
- Columba versicolor
- Columba vitiensis
- Columba vitiensis vitiensis
- Columbidae
- Columbiformes
- Columbina
- Columbina buckleyi
- Columbina cruziana
- Columbina cyanopis
- Columbina inca
- Columbina minuta
- Columbina minuta elaeodes
- Columbina passerina
- Columbina passerina nigrirostris
- Columbina picui
- Columbina picui picui
- Columbina squamata
- Columbina squamatta
- Columbina squammata
- Columbina squammata ridgwayi.
- Columbina talpacoti
- Columbina talpacoti rufipennis
- Columbina talpatoci rufipennis
- Colusa National Wildlife Refuge
- Colusa National Wildlife Refuge(Colusa)
- Comb-crested Jacana
- Comb Duck
- Comechingones Cinclodes
- Common Babax
- Common Babbler
- Common Barn Owl
- Common Black-Hawk
- Common Black Hawk
- Common Blue Tit
- Common Bristlebill
- Common Bronzewing
- Common Brown Babbler
- Common Bulbul
- Common Bullfinch
- Common Bush-Tanager
- Common Bush Tanager
- Common Bushtit
- Common Bustard-Quail
- Common Buttonquail
- Common Buzzard
- Common Cactus-Finch
- Common Cactus Finch
- Common Chaffinch
- Common Chestnut-winged Starling
- Common Chiffchaff
- Common Chlorospingus
- Common Chough
- Common Cicadabird
- Common Coot
- Common Cormorant
- Common Crane
- Common Crossbill
- Common Crow
- Common Crow pheasant
- Common Cuckoo
- Common Currawong
- Common Dipper
- Common Diuca-Finch
- Common Diuca Finch
- Common Diving-Petrel
- Common Diving Petrel
- Common Dove
- Common Eider


