- Osprey
- Owl
- Ostrich
- Oriole
- Oystercatcher
- Ovenbird
- Orange Bishop
- Olive Warbler
- Olive-backed Sunbird
- Olive-sided Flycatcher
- Orange-bellied Parrot
- Orange-cheeked Waxbill
- Orange-crowned Warbler
- Oriental Pratincole
- Oriental Skylark
- Oriental Turtle Dove
- Oriental White-eye
- Oriental Dwarf Kingfisher
- Orange-fronted Parakeet
- Orange-throated Sunangel
- Orange-winged Amazon
- Orange-breasted Bunting
- Orange-crowned Fairywren
- Orange-footed Scrubfowl
- Orange-bellied Leafbird
- Orange-bellied Trogon
- Orange-breasted Green Pigeon
- Orange-breasted Sunbird
- Orange-chinned Parakeet
- Orange-fronted Parakeet
- Orange-throated Sunangel
- Orange-winged Amazon
- Orange-breasted Bunting
- Orange-crowned Fairywren
- Orange-footed Scrubfowl
- Orange-bellied Leafbird
- Orange-bellied Trogon
- Orange-breasted Green Pigeon
- Orange-breasted Sunbird
- Orange-chinned Parakeet
- Orange-fronted Parakeet
- Orange-throated Sunangel
- Orange-winged Amazon
- Orange-breasted Bunting
- Orange-crowned Fairywren
- Orange-footed Scrubfowl
- Orange-bellied Leafbird
- Orange-bellied Trogon
- Orange-breasted Green Pigeon
- Orange-breasted Sunbird
- Orange-chinned Parakeet
- Osprey
- Owl
- Ostrich
- Oriole
- Oystercatcher
- Ovenbird
- Orange Bishop
- Olive Warbler
- Olive-backed Sunbird
- Olive-sided Flycatcher
- Orange-bellied Parrot
- Orange-cheeked Waxbill
- Orange-crowned Warbler
- Oriental Pratincole
- Oriental Skylark
- Oriental Turtle Dove
- Oriental White-eye
- Oriental Dwarf Kingfisher
- Orange-fronted Parakeet
- Orange-throated Sunangel
- Orange-winged Amazon
- Orange-breasted Bunting
- Orange-crowned Fairywren
- Orange-footed Scrubfowl
- Orange-bellied Leafbird
- Orange-bellied Trogon
- Orange-breasted Green Pigeon
- Orange-breasted Sunbird
- Orange-chinned Parakeet
- Orange-fronted Parakeet
- Orange-throated Sunangel
- Orange-winged Amazon
- Orange-breasted Bunting
- Orange-crowned Fairywren
- Orange-footed Scrubfowl
- Orange-bellied Leafbird
- Orange-bellied Trogon
- Orange-breasted Green Pigeon
- Orange-breasted Sunbird
- Orange-chinned Parakeet
- Orange-fronted Parakeet
- Orange-throated Sunangel
- Orange-winged Amazon
- Orange-breasted Bunting
- Orange-crowned Fairywren
- Orange-footed Scrubfowl
- Orange-bellied Leafbird
- Orange-bellied Trogon
- Orange-breasted Green Pigeon
- Orange-breasted Sunbird
- Orange-chinned Parakeet
- Osprey
- Owl
- Ostrich
- Oriole
- Oystercatcher
- Ovenbird
- Orange Bishop
- Olive Warbler
- Olive-backed Sunbird
- Olive-sided Flycatcher
- Orange-bellied Parrot
- Orange-cheeked Waxbill
- Orange-crowned Warbler
- Oriental Pratincole
- Oriental Skylark
- Oriental Turtle Dove
- Oriental White-eye
- Oriental Dwarf Kingfisher
- Orange-fronted Parakeet
- Orange-throated Sunangel
- Orange-winged Amazon
- Orange-breasted Bunting
- Orange-crowned Fairywren
- Orange-footed Scrubfowl
- Orange-bellied Leafbird
- Orange-bellied Trogon
- Orange-breasted Green Pigeon
- Orange-breasted Sunbird
- Orange-chinned Parakeet
- Orange-fronted Parakeet
- Orange-throated Sunangel
- Orange-winged Amazon
- Orange-breasted Bunting
- Orange-crowned Fairywren
- Orange-footed Scrubfowl
- Orange-bellied Leafbird
- Orange-bellied Trogon
- Orange-breasted Green Pigeon
- Orange-breasted Sunbird
- Orange-chinned Parakeet
- Osprey
- Owl
- Ostrich
- Oriole
- Oystercatcher
- Ovenbird
- Orange Bishop
- Olive Warbler
