| Common Name | Scientific name |
|---|---|
| Jet Antbird | Cercomacra nigricans |
| Jouanin's Petrel | Bulweria fallax |
| Juan Fernandez Petrel | Pterodroma externa |
| Juniper Titmouse | Baeolophus ridgwayi |
| Kakawahie | Paroreomyza flammea |
| Kalij Pheasant | Lophura leucomelanos |
| Kamao | Myadestes myadestinus |
| Kamchatka Leaf Warbler | Phylloscopus examinandus |
| Kauai Akialoa | Akialoa stejnegeri |
| Kauai Amakihi | Chlorodrepanis stejnegeri |
| Kauai Elepaio | Chasiempis sclateri |
| Kauai Nukupuu | Hemignathus hanapepe |
| Kauai Oo | Moho braccatus |
| Keel-billed Motmot | Electron carinatum |
| Keel-billed Toucan | Ramphastos sulfuratus |
| Kelp Gull | Larus dominicanus |
| Kentish Plover | Charadrius alexandrinus |
| Kentucky Warbler | Geothlypis formosa |
| Kermadec Petrel | Pterodroma neglecta |
| Key West Quail-Dove | Geotrygon chrysia |
| Killdeer | Charadrius vociferus |
| King Eider | Somateria spectabilis |
| King Rail | Rallus elegans |
| King Vulture | Sarcoramphus papa |
| Kioea | Chaetoptila angustipluma |
RingBase adheres to EURING codes.
