- Magnificent Frigatebird
- Mallard
- Mandarin Duck
- Mangrove Warbler
- Many-banded Aracari
- Maroon-tailed Parakeet
- Marsh Warbler
- Masked Crimson Tanager
- Masked Flowerpiercer
- Masked Lapwing
- Masked Trogon
- Meadow Pipit
- Melodious Warbler
- Middle Spotted Woodpecker
- Montagu's Harrier
- Montane Woodcreeper
- Montezuma Oropendola
- Morepork
- Moss-backed Tanager
- Mountain Thrush
- Mountain Wren
- Muscovy Duck
- Mute Swan