- Maccoa Duck
- Mackinnon's Shrike
- Madagascar Blue Vanga
- Madagascar Buttonquail
- Madagascar Cuckoo
- Madagascar Cuckooshrike
- Madagascar Fish Eagle
- Madagascar Harrier-Hawk
- Madagascar Hoopoe
- Madagascar Jacana
- Madagascar Lark
- Madagascar Magpie-Robin
- Madagascar Mannikin
- Madagascar Nightjar
- Madagascar Plover
- Madagascar Pygmy Kingfisher
- Madagascar Sandgrouse
- Madagascar Spinetail
- Madagascar Stonechat
- Madagascar Swamp Warbler
- Madagascar Wagtail
- Magellanic Oystercatcher
- Magellanic Penguin
- Magellanic Plover
- Magellanic Snipe
- Magellanic Tapaculo
- Magellanic Woodpecker
- Magenta-throated Woodstar
- Magnificent Bird-of-paradise
- Magnificent Frigatebird
- Magnolia Warbler
- Magpie-lark
- Magpie Mannikin
- Magpie Shrike
- Magpie Tanager
- Maguari Stork
- Malachite Kingfisher
- Malachite Sunbird
- Malagasy Brush Warbler
- Malagasy Bulbul
- Malagasy Coucal
- Malagasy Kestrel
- Malagasy Kingfisher
- Malagasy Paradise Flycatcher
- Malagasy Pond Heron
- Malagasy Turtle Dove
- Malagasy White-eye
- Malaysian Pied Fantail
- Maleo
- Malia
- Mallard
- Mallee Emu-wren
- Malleefowl
- Mandarin Duck
- Maned Duck
- Mangrove Blue Flycatcher
- Mangrove Cuckoo
- Mangrove Sunbird
- Mangrove Swallow
- Mangrove Warbler
- Mantanani Scops Owl
- Manx Shearwater
- Many-colored Bushshrike
- Many-colored Chaco Finch
- Many-colored Rush Tyrant
- Many-striped Canastero
- Marabou Stork
- Marble-faced Bristle Tyrant
- Marbled Duck
- Marbled Frogmouth
- Marbled Honeyeater
- Marico Sunbird
- Marmora's Warbler
- Maroon-backed Accentor
- Maroon-chested Ground Dove
- Maroon Oriole
- Marsh Sandpiper
- Marsh Tchagra
- Marsh Tit
- Marsh Warbler
- Marshall's Iora
- Martial Eagle
- Mascarene Martin
- Masked Bowerbird
- Masked Flowerpiercer
- Masked Lapwing
- Masked Mountain Tanager
- Masked Tityra
- Masked Trogon
- Masked Water Tyrant
- Masked Woodswallow
- Masked Yellowthroat
- Matinan Blue Flycatcher
- McGregor's Cuckooshrike
- Meadow Bunting
- Meadow Pipit
- Mealy Amazon
- Mediterranean Gull
- Medium Egret
- Medium Ground Finch
- Medium Tree Finch
- Melanesian Megapode
- Melodious Warbler
- Merlin
- Metallic-green Tanager
- Metallic-winged Sunbird
- Metallic Pigeon
- Metallic Starling
- Mexican Violetear
- Middle Spotted Woodpecker
- Mimic Honeyeater
- Mindanao Blue Fantail
- Mindanao Hornbill
- Mindanao Pygmy Babbler
- Mindanao White-eye
- Mistle Thrush
- Mistletoe Tyrannulet
- Moltoni's Warbler
- Moluccan Flycatcher
- Moluccan Hanging Parrot
- Moluccan King Parrot
- Moluccan Myzomela
- Moluccan Owlet-nightjar
- Moluccan Scops Owl
- Moluccan Starling
- Mongolian Finch
- Mongolian Ground Jay
- Mongolian Lark
- Mongolian Short-toed Lark
- Monk Parakeet
- Montagu's Harrier
- Montane Foliage-gleaner
- Montane Woodcreeper
- Moorland Chat
- Morepork
- Mottled Berryhunter
- Mottled Owl
- Mottled Spinetail
- Mottled Wood Owl
- Mountain Bulbul
- Mountain Buzzard
- Mountain Cacique
- Mountain Chiffchaff
- Mountain Elaenia
- Mountain Firetail
- Mountain Hawk-Eagle
- Mountain Imperial Pigeon
- Mountain Masked Apalis
- Mountain Mouse-warbler
- Mountain Oriole
- Mountain Owlet-nightjar
- Mountain Peltops
- Mountain Pipit
- Mountain Swiftlet
- Mountain Tailorbird
- Mountain Wagtail
- Mountain Wheatear
- Mountain Wren
- Mourning Collared Dove
- Mourning Dove
- Mourning Sierra Finch
- Moustached Antpitta
- Moustached Antwren
- Moustached Barbet
- Moustached Grass Warbler
- Moustached Treeswift
- Moustached Warbler
- Mrs. Gould's Sunbird
- Muisca Antpitta
- Mulga Parrot
- Multicolored Tanager
- Muscovy Duck
- Musk Duck
- Musk Lorikeet
- Mute Swan