The lists are mostly based on the distribution maps in Howell & Webb -95, as well as the reliable observations in ebird. But I have also used the lists provided by CONABIO when no other information has been available. Other sources will be used if necessary.The taxonomy follows ebird/Clements (2018).
True - Species that normally do not occur outside of Mexico.
Regionals - US border states plus area south of Mexico covered in Howell & Webb, -95.
Central American - Species that have a distribution ranging from Mexico to Panama, both included.
Yucatán endemics (the Mexican part of the peninsula plus Belize and northern Guatemala).