- MacGregor's Honeyeater
- Mackinnon's Shrike
- Madagascar Cisticola
- Madagascar Cuckoo-Hawk
- Madagascar Forest Rail
- Madagascar Harrier-Hawk
- Madagascar Partridge
- Madagascar Swamp Warbler
- Magdalena Antbird
- Magellanic Oystercatcher
- Magellanic Penguin
- Magellanic Plover
- Magellanic Snipe
- Magellanic Woodpecker
- Magenta-throated Woodstar
- Maghreb Lark
- Magnificent Riflebird
- Magpie Shrike
- Magpie Starling
- Maguari Stork
- Malabar Lark
- Malabar Whistling Thrush
- Malagasy Brush Warbler
- Malagasy Harrier
- Malayan Crested Fireback
- Malayan Night Heron
- Malaysian Blue Flycatcher
- Mali Firefinch
- Malindi Pipit
- Manchurian Bush Warbler
- Maned Owl
- Mangrove Blue Flycatcher
- Mangrove Kingfisher
- Mangrove Rail
- Mangrove Whistler
- Mantanani Scops Owl
- Mantled Hawk
- Manu Parrotlet
- Many-spotted Hummingbird
- Maranon Pigeon
- Marbled Wood Quail
- Marcapata Spinetail
- Marico Flycatcher
- Marico Sunbird
- Maroon-bellied Parakeet
- Maroon-breasted Philentoma
- Maroon-fronted Parrot
- Maroon Oriole
- Maroon Woodpecker
- Marsh Owl
- Marsh Seedeater
- Marshall's Iora
- Marvelous Spatuletail
- Mascarene Martin
- Masked Finch
- Masked Flowerpiercer
- Masked Saltator
- Masked Tanager
- Masked Trogon
- Masked Water Tyrant
- Matinan Blue Flycatcher
- Mato Grosso Antbird
- Mbulu White-eye
- Meadow Bunting
- Mealy Amazon
- Medium Ground Finch
- Melancholy Woodpecker
- Menetries's Warbler
- Mentawai Scops Owl
- Merlin
- Metallic Pigeon
- Mexican Duck
- Mexican Hermit
- Mexican Jay
- Mexican Sheartail
- Mexican Woodnymph
- Mid-mountain Berrypecker
- Middle American Screech Owl
- Mikado Pheasant
- Military Macaw
- Mimic Honeyeater
- Minahasa Masked Owl
- Minas Gerais Tyrannulet
- Miombo Blue-eared Starling
- Miombo Scrub Robin
- Miombo Wren-Warbler
- Mishana Tyrannulet
- Mistletoe Tyrannulet
- Modest Tiger Parrot
- Moluccan Drongo-Cuckoo
- Moluccan Hanging Parrot
- Moluccan King Parrot
- Moluccan Megapode
- Moluccan Owlet-nightjar
- Moluccan Scops Owl
- Mongolian Finch
- Mongolian Ground Jay
- Mongolian Lark
- Montane Widowbird
- Monteiro's Hornbill
- Monteiro's Storm Petrel
- Montezuma Oropendola
- Montezuma Quail
- Moreau's Sunbird
- Morelet's Seedeater
- Morotai Friarbird
- Mottle-cheeked Tyrannulet
- Mottled Berryhunter
- Mottled Owl
- Mottled Spinetail
- Mountain Barbet
- Mountain Blackeye
- Mountain Bluebird
- Mountain Bulbul
- Mountain Buzzard
- Mountain Elaenia
- Mountain Hawk-Eagle
- Mountain Leaf Warbler
- Mountain Masked Apalis
- Mountain Mouse-warbler
- Mountain Owlet-nightjar
- Mountain Pygmy Owl
- Mountain Scops Owl
- Mountain Serpent Eagle
- Mountain Thornbill
- Mountain Trogon
- Mountain Velvetbreast
- Mountain Wren
- Mountain Wren-Babbler
- Mourning Sierra Finch
- Mouse-colored Tapaculo
- Moustached Antpitta
- Moustached Brushfinch
- Moustached Puffbird
- Moustached Tinkerbird
- Moustached Treeswift
- Moustached Woodcreeper
- Moustached Wren
- Mrs. Gould's Sunbird
- Mugimaki Flycatcher
- Muisca Antpitta
- Mulga Parrot
- Multicolored Tanager
- Munchique Wood Wren