| Common Name | Scientific name |
|---|---|
| Common Redstart | Phoenicurus phoenicurus |
| Common Reed Bunting | Emberiza schoeniclus |
| Common Ringed Plover | Charadrius hiaticula |
| Common Rock Thrush | Monticola saxatilis |
| Common Rosefinch | Carpodacus erythrinus |
| Common Sandpiper | Actitis hypoleucos |
| Common Scops-Owl | Otus scops |
| Common Scoter | Melanitta nigra |
| Common Shelduck | Tadorna tadorna |
| Common Snipe | Gallinago gallinago |
| Common Starling | Sturnus vulgaris |
| Common Swift | Apus apus |
| Common Tern | Sterna hirundo |
| Common Tody-Flycatcher | Todirostrum cinereum |
| Common Waxbill | Estrilda astrild |
| Common Whitethroat | Sylvia communis |
| Common Wood Pigeon | Columba palumbus |
| Common Yellowthroat | Geothlypis trichas |
| Connecticut Warbler | Oporornis agilis |
| Cook's Petrel | Pterodroma cookii |
| Cooper's Hawk | Accipiter cooperii |
| Coppery-headed Emerald | Elvira cupreiceps |
| Cordilleran Flycatcher | Empidonax occidentalis |
| Corn Bunting | Emberiza calandra |
| Corn Crake | Crex crex |
RingBase adheres to EURING codes.
