- Cinnyris loveridgei
- Cinnyris ludovicensis
- Cinnyris manoensis
- Cinnyris mariquensis
- Cinnyris mediocris
- Cinnyris minullus
- Cinnyris nectarinioides
- Cinnyris neergaardi
- Cinnyris notatus
- Cinnyris osea
- Cinnyris oustaleti
- Cinnyris pembae
- Cinnyris prigoginei
- Cinnyris pulchella
- Cinnyris pulchellus
- Cinnyris regia
- Cinnyris regius
- Cinnyris reichenowi
- Cinnyris rockefelleri
- Cinnyris rufipennis
- Cinnyris shelleyi
- Cinnyris solaris
- Cinnyris souimanga
- Cinnyris sovimanga
- Cinnyris stuhlmanni
- Cinnyris superbus
- Cinnyris talatala
- Cinnyris ursulae
- Cinnyris usambaricus
- Cinnyris venustus
- Cinnyris whytei
- Cipo Canastero
- Cipo Cinclodes
- Circaetus
- Circaetus beaudouini
- Circaetus cinerascens
- Circaetus cinereus
- Circaetus fasciolatus
- Circaetus gallicus
- Circaetus pectoralis
- Circeo National Park
- Circeo National Park Italy
- Circus
- Circus Aeruginosus
- Circus Buffoni
- Circus aeruginosus
- Circus approximans
- Circus assimilis
- Circus buffoni
- Circus cinereus
- Circus cyaneus
- Circus eylesi
- Circus hudsonius
- Circus macrosceles
- Circus macrourus
- Circus maillardi
- Circus maurus
- Circus melanoleucos
- Circus pygargus
- Circus ranivorus
- Circus spilonotus
- Circus spilothorax
- Ciridops
- Ciridops anna
- Cirl Bunting
- Cissa
- Cissa chinensis
- Cissa chinensis robinsoni
- Cissa hypoleuca
- Cissa jefferyi
- Cissa thalassina
- Cissilopha
- Cissilopha beecheii
- Cissilopha melanocyaneus
- Cissilopha sanblasianus
- Cissilopha yucatanicus
- Cissomela pectoralis
- Cissopis
- Cissopis leveriana
- Cissopis leverianus
- Cisticola
- Cisticola Juncidis
- Cisticola aberdare
- Cisticola aberrans
- Cisticola aberrans aberrans
- Cisticola angolensis
- Cisticola angusticauda
- Cisticola anonymus
- Cisticola aridulus
- Cisticola ayresii
- Cisticola bodessa
- Cisticola brachypterus
- Cisticola brunnescens
- Cisticola bulliens
- Cisticola cantans
- Cisticola carruthersi
- Cisticola cherina
- Cisticola chiniana
- Cisticola chubbi
- Cisticola chubbi chubbi
- Cisticola cinereolus
- Cisticola cinnamomeus
- Cisticola dambo
- Cisticola discolor
- Cisticola distinctus
- Cisticola dorsti
- Cisticola emini
- Cisticola erythrops
- Cisticola exilis
- Cisticola exilis volitans
- Cisticola eximius
- Cisticola fulvicapilla
- Cisticola galactotes
- Cisticola galactotes lugubris
- Cisticola guinea
- Cisticola haematocephalus
- Cisticola haesitatus
- Cisticola hunteri
- Cisticola incanus
- Cisticola juncidis
- Cisticola juncidis salimalii
- Cisticola lais
- Cisticola lais distinctus
- Cisticola lateralis
- Cisticola lepe
- Cisticola luapula
- Cisticola lugubris
- Cisticola marginatus
- Cisticola melanurus
- Cisticola mongalla
- Cisticola nana
- Cisticola nanus
- Cisticola natalensis
- Cisticola nigriloris
- Cisticola njombe
- Cisticola pipiens
- Cisticola restrictus
- Cisticola robustus
- Cisticola ruficeps
- Cisticola rufilatus
- Cisticola rufus
- Cisticola subruficapilla
- Cisticola taciturnus
- Cisticola textrix
- Cisticola tinniens
- Cisticola troglodytes
- Cisticola woosnami
- Cisticolidae
- Cistothorus
- Cistothorus apolinari
- Cistothorus apolinari hernandezi
- Cistothorus meridae
- Cistothorus palustris
- Cistothorus palustris paludicola
- Cistothorus platensis
- Cistothorus platensis falklandicus
- Cistothorus platensis falklandii
- Cistothorus stellaris
- Citreoline Trogon
- Citril Finch
- Citrine Canary-Flycatcher
- Citrine Canary Flycatcher
- Citrine Lorikeet
- Citrine Wagtail
- Citrine Warbler
- Citrine White-eye
- Citron-bellied Attila
- Citron-headed Yellow-Finch
- Citron-headed Yellow Finch
- Citron-throated Toucan
- Cittura
- Cittura cyanotis
- Cittura cyanotis cyanotis
- Ciénaga de Zapata
- Cladorhynchus
- Cladorhynchus leucocephalus
- Clamator
- Clamator Glandarius
- Clamator coromandus
- Clamator glandarius
- Clamator jacobinus
- Clamator jacobinus pica
- Clamator levaillantii
- Clamorous Reed-Warbler
- Clamorous Reed-warbler
- Clamorous Reed Warbler
- Clanga clanga
- Clanga hastata
- Clanga pomarina
- Clangula
- Clangula hyemalis
- Clapper Lark
- Clapper Rail
- Clapperton's Francolin
- Claravis
- Claravis geoffroyi
- Claravis godefrida
- Claravis mondetoura
- Claravis pretiosa
- Claret-breasted Fruit-Dove
- Claret-breasted Fruit Dove
- Clarion Wren
- Clark's Grebe
- Clark's Nutcracker
- Clark County Wetlands Park
- Clarke's Weaver
- Claudia's Leaf-Warbler
- Claudia's Leaf Warbler
- Clay-colored Robin
- Clay-colored Sparrow
- Clay-colored Thrush
- Clay-coloured Robin
- Clay-coloured Sparrow
- Clay-coloured Thrush
- Cleptornis
- Cleptornis marchei
- Cleveland
- Cley
- Cley-Salthouse Marshes
- Cley NWT
- Clibanornis
- Clibanornis dendrocolaptoides
- Clibanornis erythrocephalus
- Clibanornis rectirostris
- Clibanornis rubiginosus
- Clibanornis rufipectus
- Clicking Peltops
- Clicking Shrike-Babbler
- Clicking Shrike Babbler
- Cliff Flycatcher
- Cliff Parakeet
- Cliff Swallow
- Cliff Thrush
- Clifford E. Lee Nature Sanctuary
- Clifford E. Lee Nature Sanctuary(Southwest of Edmonton)
- Cliffs of Moher
- Climacteridae
- Climacteris
- Climacteris affinis
- Climacteris erythrops
- Climacteris melanura
- Climacteris melanurus
- Climacteris melanurus wellsi
- Climacteris picumnus
- Climacteris rufa
- Climacteris rufous
- Climacteris rufus
- Clinking Currawong
- Cloncurry Parrot
- Clos-du-Doubs
- Clos-du-Doubs (Switzerland)
- Clos-du-Doubs Nature Reserve
- Clot de Galvany
- Cloud-forest Nightjar
- Cloud-forest Pygmy-Owl
- Cloud-forest Pygmy Owl
- Cloud-forest Robin
- Cloud-forest Screech-Owl
- Cloud-forest Screech Owl
- Cloud-scraping Cisticola
- Cloud Cisticola
- Clouded Shrike
- Cloudforest Nightjar
- Cloudforest Pygmy-Owl
- Cloudforest Pygmy Owl
- Cloudforest Screech-Owl
- Cloudforest Screech Owl
- Cloven-feathered Dove
- Club-winged Manakin
- Clyde Estuary
- Clyde estuary
- Clypicterus
- Clypicterus oseryi
- Clytoceyx
- Clytoceyx rex
- Clytoctantes
- Clytoctantes alixii
- Clytoctantes atrogularis
- Clytolaema
- Clytolaema rubricauda
- Clytomyias
- Clytomyias insignis
- Clytorhynchus
- Clytorhynchus hamlini
- Clytorhynchus nigrogularis
- Clytorhynchus pachycephaloides
- Clytorhynchus sanctaecrucis
- Clytorhynchus vitiensis
- Clytorhynchus vitiensis layardi
- Clytospiza
- Clytospiza monteiri
- Cnemarchus
- Cnemarchus erythropygius
- Cnemathraupis
- Cnemathraupis aureodorsalis
- Cnemathraupis eximia
- Cnemophilidae
- Cnemophilus
- Cnemophilus loriae
- Cnemophilus macgregorii
- Cnemoscopus
- Cnemoscopus rubrirostris
- Cnemoscopus rubrirostris chrysogaster
- Cnemotriccus
- Cnemotriccus fuscatus
- Cnemotriccus fuscatus cabanisi
- Cnipodectes
- Cnipodectes subbrunneus
- Coachwhip-bird
- Coachwhip Bird
- Coahuila
- Coal-crested Finch
- Coal Tit
- Coastal Boubou
- Coastal Cisticola
- Coastal Miner
- Coastal Screech Owl
- Cobalt-winged Parakeet
- Cobb's Wren
- Coccopygia
- Coccopygia bocagei
- Coccopygia melanotis
- Coccopygia quartinia
- Coccothraustes
- Coccothraustes abeillei
- Coccothraustes coccothraustes
- Coccothraustes coccothraustes coccothraustes
- Coccothraustes vespertinus
- Coccycolius
- Coccycolius iris
- Coccycua cinerea
- Coccycua minuta
- Coccycua minuta minuta
- Coccycua pumila
- Coccyzus
- Coccyzus americanus
- Coccyzus cinereus
- Coccyzus erythropthalmus
- Coccyzus euleri
- Coccyzus ferrugineus
- Coccyzus lansbergi
- Coccyzus longirostris
- Coccyzus melacoryphus
- Coccyzus merlini
- Coccyzus minor


