Marsh Tit 
Marsh Warbler 
Marsh widowbird 
Marsh wren 
Marshalls iora 
Mascarene Martin 
Masked bowerbird 
Masked cardinal 
Masked crimson tanager 
Masked flowerpiercer 
Masked fruiteater 
Masked gnatcatcher 
Masked lark 
Masked laughingthrush 
Masked saltator 
Masked Shrike 
Masked tanager 
Masked Tityra 
Masked water tyrant 
Masked yellowthroat 
Mayan antthrush 
Meadow Pipit 
Melodious warbler 
Menetries's warbler