obscurum, Dicæum, [636]
obscurus, Turdus, [549]
occipitalis, Hypothymis, [451], [733]
Leucotreron, [37], [726]
Muscicapa, [451]
Phabotreron, [34]
Phapitreron, [34]
Ptilopus, [37]
Ramphiculus, [37]
occularis, Rhinomyias, [470]
Oceanodroma, [84]
species, [84]
ocellata, Turnix, [20]
ocellatus, Oriolus, [20]
ochotensis, Sylvia (Locustella), [568]
Locustella, [568]
ochropus, Helodromas, [123], [727]
Ochthodromus, [105]
geoffroyi, [106], [727]
mongolus, [107]
veredus, [108], [727]