- Christmas Island Warbler
- Christmas Island White-eye
- Christmas Shearwater
- Christmas White-eye
- Chroicocephalus
- Chroicocephalus brunnicephalus
- Chroicocephalus bulleri
- Chroicocephalus cirrocephalus
- Chroicocephalus cirrocephalus cirrocephalus
- Chroicocephalus cirrocephalus pioicephalus
- Chroicocephalus genei
- Chroicocephalus hartlaubii
- Chroicocephalus maculipennis
- Chroicocephalus novaehollandiae
- Chroicocephalus novaehollandiae forsteri
- Chroicocephalus novaehollandiae novaehollandiae
- Chroicocephalus novaehollandiae scopulinus
- Chroicocephalus philadelphia
- Chroicocephalus ridibundus
- Chroicocephalus saundersi
- Chroicocephalus scopulinus
- Chroicocephalus serranus
- Chrysococcyx
- Chrysococcyx basalis
- Chrysococcyx caprius
- Chrysococcyx crassirostris
- Chrysococcyx cupreus
- Chrysococcyx flavigularis
- Chrysococcyx klaas
- Chrysococcyx lucidus
- Chrysococcyx lucidus lucidus
- Chrysococcyx maculatus
- Chrysococcyx megarhynchus
- Chrysococcyx meyeri
- Chrysococcyx meyerii
- Chrysococcyx minutillus
- Chrysococcyx osculans
- Chrysococcyx ruficollis
- Chrysococcyx rufomerus
- Chrysococcyx russatus
- Chrysococcyx xanthorhynchus
- Chrysocolaptes
- Chrysocolaptes erythrocephalus
- Chrysocolaptes festivus
- Chrysocolaptes guttacristatus
- Chrysocolaptes haematribon
- Chrysocolaptes lucidus
- Chrysocolaptes lucidus lucidus
- Chrysocolaptes stricklandi
- Chrysocolaptes strictus
- Chrysocolaptes xanthocephalus
- Chrysocorythus
- Chrysocorythus estherae
- Chrysoena viridis
- Chrysolampis
- Chrysolampis mosquitus
- Chrysolophus
- Chrysolophus amherstiae
- Chrysolophus pictus
- Chrysominla
- Chrysominla strigula
- Chrysomma
- Chrysomma altirostre
- Chrysomma poecilotis
- Chrysomma sinense
- Chrysomus
- Chrysomus flavus
- Chrysomus icterocephalus
- Chrysomus icterocephalus icterocephalus
- Chrysomus ruficapillus
- Chrysophlegma
- Chrysophlegma flavinucha
- Chrysophlegma mentale
- Chrysophlegma miniaceum
- Chrysoptilus punctigula
- Chrysothlypis
- Chrysothlypis chrysomelas
- Chrysothlypis salmoni
- Chrysuronia
- Chrysuronia oenone
- Chrysuronia oenone josephinae
- Chthonicola sagittata
- Chthonicola sagittatus
- Chubb's Cisticola
- Chubut Steamer-Duck
- Chubut Steamer Duck
- Chubut Steamerduck
- Chucao Tapaculo
- Chuck-Will's-Widow
- Chuck-Will's Widow
- Chuck-will's-widow
- Chukar
- Chukar Partridge
- Chunga
- Chunga burmeisteri
- Church Wood
- Church Wood RSPB Reserve (Buckinghamshire)
- Churring Cisticola
- Chusquea Tapaculo
- Chuuk
- Chuuk Broadbill
- Chuuk Monarch
- Chuuk Myiagra
- Chuuk Myiagra Flycatcher
- Cicadabird
- Ciccaba
- Ciccaba albitarsis
- Ciccaba albitarsus
- Ciccaba chacoensis
- Ciccaba huhula
- Ciccaba nigrolineata
- Ciccaba rufipes
- Ciccaba virgata
- Cichladusa
- Cichladusa arquata
- Cichladusa guttata
- Cichladusa ruficauda
- Cichlherminia
- Cichlherminia lherminieri
- Cichlocolaptes
- Cichlocolaptes leucophrus
- Cichlocolaptes mazarbarnetti
- Cichlopsis
- Cichlopsis leucogenys
- Cicinnurus
- Cicinnurus magnificus
- Cicinnurus regius
- Cicinnurus respublica
- Ciconia
- Ciconia abdimii
- Ciconia boyciana
- Ciconia ciconia
- Ciconia ciconia ciconia
- Ciconia episcopus
- Ciconia episcopus episcopus
- Ciconia maguari
- Ciconia nigra
- Ciconia stormi
- Ciconiidae
- Ciconiiformes
- Cienaga de Zapata
- Cinclidae
- Cinclidium
- Cinclidium diana
- Cinclidium frontale
- Cinclidium leucura
- Cinclidium leucurum
- Cinclidium leucurum montium
- Cinclocerthia
- Cinclocerthia gutturalis
- Cinclocerthia gutturalis macrorhyncha
- Cinclocerthia ruficauda
- Cinclodes
- Cinclodes albidiventris
- Cinclodes albiventris
- Cinclodes antarcticus
- Cinclodes antarcticus antarcticus
- Cinclodes aricomae
- Cinclodes atacamensis
- Cinclodes comechingonus
- Cinclodes espinhacensis
- Cinclodes excelsior
- Cinclodes excelsior aricomae
- Cinclodes fuscus
- Cinclodes nigrofumosus
- Cinclodes olrogi
- Cinclodes oustaleti
- Cinclodes pabsti
- Cinclodes palliatus
- Cinclodes patagonicus
- Cinclodes patagonicus chilensis
- Cinclodes taczanowskii
- Cincloramphus
- Cincloramphus cruralis
- Cincloramphus macrurus
- Cincloramphus mathewsi
- Cincloramphus timoriensis
- Cinclorhamphus cruralis
- Cinclorhamphus mathewsi
- Cinclosoma
- Cinclosoma ajax
- Cinclosoma alisteri
- Cinclosoma castaneothorax
- Cinclosoma castanotum
- Cinclosoma castanotus
- Cinclosoma cinnamomeum
- Cinclosoma clarum
- Cinclosoma marginatum
- Cinclosoma punctatum
- Cinclosomatidae
- Cinclus
- Cinclus Cinclus
- Cinclus cinclus
- Cinclus cinclus caucasicus
- Cinclus cinclus gularis
- Cinclus cinclus leucogaster
- Cinclus leucocephalus
- Cinclus mexicanus
- Cinclus mexicanus ardesiacus
- Cinclus pallasii
- Cinclus pallasii pallasii
- Cinclus pallasii tenuirostris
- Cinclus schulzi
- Cinclus schulzii
- Cinderella Waxbill
- Cinereous-breasted Spinetail
- Cinereous Antshrike
- Cinereous Becard
- Cinereous Bulbul
- Cinereous Bunting
- Cinereous Conebill
- Cinereous Finch
- Cinereous Flycatcher
- Cinereous Ground-Tyrant
- Cinereous Ground Tyrant
- Cinereous Harrier
- Cinereous Mourner
- Cinereous Owl
- Cinereous Tinamou
- Cinereous Tit
- Cinereous Tyrant
- Cinereous Vulture
- Cinereous Warbling-Finch
- Cinereous Warbling Finch
- Cinnabar Boobook
- Cinnabar Hawk-Owl
- Cinnabar Hawk Owl
- Cinnamon-backed Fantail
- Cinnamon-banded Kingfisher
- Cinnamon-bellied Flowerpiercer
- Cinnamon-bellied Ground-Tyrant
- Cinnamon-bellied Ground Tyrant
- Cinnamon-bellied Imperial-Pigeon
- Cinnamon-bellied Imperial Pigeon
- Cinnamon-breasted Bunting
- Cinnamon-breasted Rock Bunting
- Cinnamon-breasted Tit
- Cinnamon-breasted Tody-Tyrant
- Cinnamon-breasted Tody Tyrant
- Cinnamon-breasted Warbler
- Cinnamon-breasted Whistler
- Cinnamon-browed Melidectes
- Cinnamon-capped Spinetail
- Cinnamon-chested Bee-eater
- Cinnamon-chested Flycatcher
- Cinnamon-crested Spadebill
- Cinnamon-faced Tyrannulet
- Cinnamon-headed Green-Pigeon
- Cinnamon-headed Green Pigeon
- Cinnamon-headed Pigeon
- Cinnamon-rumped Foliage-gleaner
- Cinnamon-rumped Seedeater
- Cinnamon-rumped Trogon
- Cinnamon-sided Hummingbird
- Cinnamon-tailed Fantail
- Cinnamon-tailed Sparrow
- Cinnamon-throated Cave Swallow
- Cinnamon-throated Hermit
- Cinnamon-throated Swallow
- Cinnamon-throated Woodcreeper
- Cinnamon-vented Piha
- Cinnamon Attila
- Cinnamon Becard
- Cinnamon Bittern
- Cinnamon Bracken-Warbler
- Cinnamon Bracken Warbler
- Cinnamon Flycatcher
- Cinnamon Frogmouth
- Cinnamon Ground-Dove
- Cinnamon Ground Dove
- Cinnamon Hummingbird
- Cinnamon Ibon
- Cinnamon Little-Bittern
- Cinnamon Manakin
- Cinnamon Manakin-Tyrant
- Cinnamon Manakin Tyrant
- Cinnamon Neopipo
- Cinnamon Quail-thrush
- Cinnamon Quail Thrush
- Cinnamon Scops-owl
- Cinnamon Scops Owl
- Cinnamon Screech-Owl
- Cinnamon Screech Owl
- Cinnamon Sparrow
- Cinnamon Tanager
- Cinnamon Teal
- Cinnamon Tree Sparrow
- Cinnamon Tyrant
- Cinnamon Tyrant-Manakin
- Cinnamon Tyrant Manakin
- Cinnamon Tyrant or Tyrant Manakin
- Cinnamon Warbling-Finch
- Cinnamon Warbling Finch
- Cinnamon Weaver
- Cinnamon White-eye
- Cinnamon Woodpecker
- Cinnycerthia
- Cinnycerthia fulva
- Cinnycerthia olivascens
- Cinnycerthia peruana
- Cinnycerthia unirufa
- Cinnyricinclus
- Cinnyricinclus femoralis
- Cinnyricinclus leucogaster
- Cinnyricinclus sharpii
- Cinnyris
- Cinnyris Jugularis
- Cinnyris abbotti
- Cinnyris afer
- Cinnyris afra
- Cinnyris asiaticus
- Cinnyris asiaticus asiaticus
- Cinnyris batesi
- Cinnyris bifasciatus
- Cinnyris bouvieri
- Cinnyris buettikoferi
- Cinnyris chalcomelas
- Cinnyris chalybeus
- Cinnyris chalybeus chalybeus
- Cinnyris chloropygius
- Cinnyris coccinigastrus
- Cinnyris comorensis
- Cinnyris congensis
- Cinnyris coquerellii
- Cinnyris cupreus
- Cinnyris dussumieri
- Cinnyris erythrocerca
- Cinnyris erythrocercus
- Cinnyris fuelleborni
- Cinnyris fusca
- Cinnyris fuscus
- Cinnyris gertrudis
- Cinnyris habessinicus
- Cinnyris hofmanni
- Cinnyris humbloti
- Cinnyris johannae
- Cinnyris jugularis
- Cinnyris jugularis aurora
- Cinnyris jugularis flammaxillaris
- Cinnyris jugularis flavigastra
- Cinnyris jugularis frenatus
- Cinnyris jugularis ornatus
- Cinnyris lotenia
- Cinnyris lotenius
- Cinnyris loveridgei


