The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
(first | last) View (previous 50 | next 50) (20 | 50 | 100 | 250 | 500)- Ochthornis (1 member)
- Ocreatus (1 member)
- Oculocincta (1 member)
- Ocyalus (0 members)
- Ocyceros (3 members)
- Ocyphaps (0 members)
- Odontophoridae (10 members)
- Odontophorus (15 members)
- Odontorchilus (2 members)
- Odontospiza (1 member)
- Oedistoma (2 members)
- Oena (1 member)
- Oenanthe (28 members)
- Ognorhynchus (1 member)
- Ohio (3 members)
- Oklahoma (1 member)
- Oman (1 member)
- Oncostoma (2 members)
- Oneillornis (0 members)
- Ontario (6 members)
- Onychognathus (11 members)
- Onychoprion (4 members)
- Onychorhynchus (1 member)
- Onychostruthus (1 member)
- Ophrydornis (1 member)
- Ophrysia (1 member)
- Opisthocomidae (1 member)
- Opisthocomiformes (1 member)
- Opisthocomus (1 member)
- Opisthoprora (1 member)
- Oporornis (1 member)
- Orchesticus (1 member)
- Oregon (1 member)
- Oreocharis (1 member)
- Oreoica (1 member)
- Oreoicidae (3 members)
- Oreolais (2 members)
- Oreomanes (1 member)
- Oreomystis (1 member)
- Oreonympha (1 member)
- Oreophasis (1 member)
- Oreophilais (0 members)
- Oreopholus (1 member)
- Oreophylax (0 members)
- Oreopsar (1 member)
- Oreopsittacus (1 member)
- Oreornis (1 member)
- Oreortyx (1 member)
- Oreoscoptes (1 member)
- Oreoscopus (1 member)


