| Temminck's Courser Cursorius temminckii | Charadriiformes / Glareolidae | LC |
| Vietnamese Cutia Cutia legalleni | Passeriformes / Leiothrichidae | NT |
| Purple Honeycreeper Cyanerpes caeruleus | Passeriformes / Thraupidae | LC |
| Red-legged Honeycreeper Cyanerpes cyaneus | Passeriformes / Thraupidae | LC |
| Shining Honeycreeper Cyanerpes lucidus | Passeriformes / Thraupidae | LC |
| Short-billed Honeycreeper Cyanerpes nitidus | Passeriformes / Thraupidae | LC |
| Blue-backed Tanager Cyanicterus cyanicterus | Passeriformes / Thraupidae | LC |
| Eurasian Blue Tit Cyanistes caeruleus | Passeriformes / Paridae | LC |
| African Blue Tit Cyanistes teneriffae | Passeriformes / Paridae | LC |
| Blue-winged Goose Cyanochen cyanoptera | Anseriformes / Anatidae | NT |
| Blue Jay Cyanocitta cristata | Passeriformes / Corvidae | LC |
| Steller's Jay Cyanocitta stelleri | Passeriformes / Corvidae | LC |
| Blue Bunting Cyanocompsa parellina | Passeriformes / Cardinalidae | LC |
| Black-chested Jay Cyanocorax affinis | Passeriformes / Corvidae | LC |
| Purplish-backed Jay Cyanocorax beecheii | Passeriformes / Corvidae | LC |
| Cayenne Jay Cyanocorax cayanus | Passeriformes / Corvidae | LC |
| Plush-crested Jay Cyanocorax chrysops | Passeriformes / Corvidae | LC |
| Azure Jay Cyanocorax coeruleus | Passeriformes / Corvidae | NT |
| Black-throated Magpie-Jay Cyanocorax colliei | Passeriformes / Corvidae | LC |
| Curl-crested Jay Cyanocorax cristatellus | Passeriformes / Corvidae | LC |
| Purplish Jay Cyanocorax cyanomelas | Passeriformes / Corvidae | LC |
| White-naped Jay Cyanocorax cyanopogon | Passeriformes / Corvidae | LC |
| Tufted Jay Cyanocorax dickeyi | Passeriformes / Corvidae | NT |
| White-throated Magpie-Jay Cyanocorax formosus | Passeriformes / Corvidae | LC |
| Azure-naped Jay Cyanocorax heilprini | Passeriformes / Corvidae | NE |
| Bushy-crested Jay Cyanocorax melanocyaneus | Passeriformes / Corvidae | LC |
| Brown Jay Cyanocorax morio | Passeriformes / Corvidae | LC |
| White-tailed Jay Cyanocorax mystacalis | Passeriformes / Corvidae | LC |
| San Blas Jay Cyanocorax sanblasianus | Passeriformes / Corvidae | LC |
| Violaceous Jay Cyanocorax violaceus | Passeriformes / Corvidae | LC |
| Green Jay Cyanocorax yncas | Passeriformes / Corvidae | LC |
| Yucatan Jay Cyanocorax yucatanicus | Passeriformes / Corvidae | LC |
| Bicolored Babbler Cyanoderma bicolor | Passeriformes / Timaliidae | LC |
| Chestnut-winged Babbler Cyanoderma erythropterum | Passeriformes / Timaliidae | LC |
| Crescent-chested Babbler Cyanoderma melanothorax | Passeriformes / Timaliidae | LC |
| Blue Cuckooshrike Cyanograucalus azureus | Passeriformes / Campephagidae | LC |
| Comoro Blue Vanga Cyanolanius comorensis | Passeriformes / Vangidae | EN |
| Madagascar Blue Vanga Cyanolanius madagascarinus | Passeriformes / Vangidae | LC |
| Burrowing Parrot Cyanoliseus patagonus | Psittaciformes / Psittacidae | LC |
| Ultramarine Grosbeak Cyanoloxia brissonii | Passeriformes / Cardinalidae | LC |
| Blue-black Grosbeak Cyanoloxia cyanoides | Passeriformes / Cardinalidae | LC |
| Glaucous-blue Grosbeak Cyanoloxia glaucocaerulea | Passeriformes / Cardinalidae | LC |
| Amazonian Grosbeak Cyanoloxia rothschildii | Passeriformes / Cardinalidae | LC |
| Silvery-throated Jay Cyanolyca argentigula | Passeriformes / Corvidae | LC |
| Black-collared Jay Cyanolyca armillata | Passeriformes / Corvidae | NE |
| Azure-hooded Jay Cyanolyca cucullata | Passeriformes / Corvidae | LC |
| White-throated Jay Cyanolyca mirabilis | Passeriformes / Corvidae | VU |
| Dwarf Jay Cyanolyca nanus | Passeriformes / Corvidae | NT |
| Beautiful Jay Cyanolyca pulchra | Passeriformes / Corvidae | NT |
| Black-throated Jay Cyanolyca pumilo | Passeriformes / Corvidae | LC |