CHECK -LIST 



OF 



North American Birds 



PREPARED BY A COMMITTEE 



OF THE 



AMERICAN ORNITHOLOGISTS' UNION 



FOURTH EDITION 



Constituting the "Systema Avium" for North America 

 North of Mexico 



Zoological Nomenclature is a means, not an end, of Zoological Science 



PUBLISHED BY THE 



AMERICAN ORNITHOLOGISTS' UNION 



LANCASTER, PA. 



1931 



