- Magellanic Oystercatcher
- Magellanic Penguin
- Magnificent Frigatebird
- Magpie Shrike
- Magpie Tanager
- Maguari Stork
- Malachite Kingfisher
- Malachite Sunbird
- Malagasy Turtle Dove
- Many-colored Rush Tyrant
- Many-spotted Hummingbird
- Marabou Stork
- Marico Flycatcher
- Marico Sunbird
- Maroon-bellied Parakeet
- Marsh Sandpiper
- Martial Eagle
- Masked Flowerpiercer
- Masked Gnatcatcher
- Masked Tityra
- Masked Water Tyrant
- Mato Grosso Antbird
- Mealy Amazon
- Meves's Starling
- Meyer's Parrot
- Mitred Parakeet
- Mocking Cliff Chat
- Monk Parakeet
- Montane Foliage-gleaner
- Monteiro's Hornbill
- Mottle-cheeked Tyrannulet
- Mottled Owl
- Mountain Caracara
- Mountain Chat
- Mountain Parakeet
- Mountain Wren
- Mourning Collared Dove
- Mourning Sierra Finch
- Moustached Wren
- Muscovy Duck
- Mute Swan