- Madeira Firecrest
- Magnificent Frigatebird
- Magnolia Warbler
- Magpie Tanager
- Malachite Kingfisher
- Mangrove Swallow
- Mangrove Warbler
- Many-banded Aracari
- Many-spotted Hummingbird
- Many-striped Canastero
- Marabou Stork
- Marbled Duck
- Marsh Sandpiper
- Marsh Tit
- Martial Eagle
- Masked Booby
- Masked Crimson Tanager
- Masked Flowerpiercer
- Masked Tityra
- Masked Trogon
- Masked Water Tyrant
- Meadow Pipit
- Mediterranean Gull
- Melodious Blackbird
- Melodious Warbler
- Mew Gull
- Mexican Sheartail
- Mexican Violetear
- Middle Spotted Woodpecker
- Mistle Thrush
- Mongolian Finch
- Monk Parakeet
- Montane Foliage-gleaner
- Montane Woodcreeper
- Montezuma Oropendola
- Morelet's Seedeater
- Mountain Wren
- Mourning Collared Dove
- Mourning Dove
- Mouse-colored Tyrannulet
- Moustached Antpitta
- Muscovy Duck
- Musician Wren
- Mute Swan
- Myrtle Warbler