- MacGregor's Honeyeater
- MacKinlay's Cuckoo-Dove
- Mackinnon's Shrike
- Madagascar Blue Pigeon
- Madagascar Buzzard
- Madagascar Fish Eagle
- Madagascar Grebe
- Madagascar Plover
- Madagascar Pratincole
- Madagascar Pygmy Kingfisher
- Madagascar Snipe
- Madagascar Stonechat
- Madeira Firecrest
- Magellanic Oystercatcher
- Magellanic Penguin
- Magellanic Plover
- Magellanic Snipe
- Magellanic Woodpecker
- Magnificent Bird-of-paradise
- Magnificent Frigatebird
- Magpie-lark
- Magpie Mannikin
- Magpie Shrike
- Magpie Tanager
- Makira Dwarf Kingfisher
- Makira Flycatcher
- Makira Honeyeater
- Makira Starling
- Malachite Kingfisher
- Malachite Sunbird
- Malagasy Coucal
- Malagasy Kingfisher
- Malagasy Pond Heron
- Malaita White-eye
- Malayan Night Heron
- Malaysian Honeyguide
- Malaysian Pied Fantail
- Malaysian Plover
- Malherbe's Parakeet
- Malindi Pipit
- Mallard
- Malleefowl
- Mandarin Duck
- Mangrove Kingfisher
- Mangrove Sunbird
- Mangrove Warbler
- Mantled Hawk
- Manu Parrotlet
- Manus Boobook
- Manus Fantail
- Manus Friarbird
- Manus Monarch
- Manx Shearwater
- Many-banded Aracari
- Many-colored Bushshrike
- Many-colored Fruit Dove
- Many-striped Canastero
- Mao
- Marabou Stork
- Marble-faced Bristle Tyrant
- Marbled Duck
- Marbled Frogmouth
- Marbled Honeyeater
- Marbled Murrelet
- Marico Flycatcher
- Marico Sunbird
- Marigold Lorikeet
- Marmora's Warbler
- Maroon-belted Chat-Tyrant
- Maroon Oriole
- Maroon Shining Parrot
- Marsh Grassbird
- Marsh Sandpiper
- Marsh Tit
- Marsh Warbler
- Marsh Widowbird
- Marsh Wren
- Marshall's Iora
- Martial Eagle
- Masked Crimson Tanager
- Masked Duck
- Masked Flowerpiercer
- Masked Fruiteater
- Masked Lapwing
- Masked Laughingthrush
- Masked Mountain Tanager
- Masked Shining Parrot
- Masked Shrike
- Masked Trogon
- Masked Water Tyrant
- Masked Woodswallow
- Matsudaira's Storm Petrel
- Maxwell's Black Weaver
- Meadow Bunting
- Meadow Pipit
- Mealy Amazon
- Mediterranean Gull
- Mediterranean Short-toed Lark
- Medium Egret
- Meek's Pygmy Parrot
- Mees's Nightjar
- Mees's White-eye
- Melancholy Woodpecker
- Melanesian Flycatcher
- Melanesian Megapode
- Melodious Warbler
- Menetries's Warbler
- Merlin
- Metallic Pigeon
- Metallic Starling
- Mexican Jay
- Mexican Violetear
- Meyer's Parrot
- Middendorff's Grasshopper Warbler
- Middle Spotted Woodpecker
- Midget Flowerpecker
- Mikado Pheasant
- Mimic Honeyeater
- Miombo Rock Thrush
- Miombo Scrub Robin
- Mistle Thrush
- Mocking Cliff Chat
- Modest Tiger Parrot
- Moltoni's Warbler
- Moluccan Scops Owl
- Mombasa Woodpecker
- Mongolian Lark
- Monk Parakeet
- Montagu's Harrier
- Montane Foliage-gleaner
- Montane Woodcreeper
- Monteiro's Bushshrike
- Moorland Chat
- Moorland Francolin
- Moreno's Ground Dove
- Mosque Swallow
- Mottled Berryhunter
- Mottled Duck
- Mottled Flowerpecker
- Mottled Mannikin
- Mottled Owl
- Mottled Petrel
- Mottled Spinetail
- Mottled Swift
- Mottled Wood Owl
- Mount Cameroon Speirops
- Mountain Bluebird
- Mountain Bulbul
- Mountain Buzzard
- Mountain Cacique
- Mountain Caracara
- Mountain Chickadee
- Mountain Chiffchaff
- Mountain Firetail
- Mountain Fulvetta
- Mountain Hawk-Eagle
- Mountain Honeyeater
- Mountain Imperial Pigeon
- Mountain Kingfisher
- Mountain Mouse-warbler
- Mountain Owlet-nightjar
- Mountain Peltops
- Mountain Pygmy Owl
- Mountain Robin
- Mountain Robin-Chat
- Mountain Saw-wing
- Mountain Velvetbreast
- Mountain Wagtail
- Mountain Wheatear
- Mountain Wren
- Mourning Collared Dove
- Mouse-colored Penduline Tit
- Mouse-colored Tapaculo
- Mouse-colored Thistletail
- Moustached Antpitta
- Moustached Grass Warbler
- Moustached Puffbird
- Moustached Tinkerbird
- Moustached Treeswift
- Moustached Warbler
- Moustached Wren
- Mrs. Gould's Sunbird
- Mugimaki Flycatcher
- Muisca Antpitta
- Multicolored Tanager
- Muscovy Duck
- Musician Wren
- Musk Duck
- Mute Swan
- Myrtle Warbler