VI PREFACE TO FOURTH EDITION. 



The List was then put into galley proof and again submitted 

 not only to members of the Committee but to a number of other 

 ornithologists who kindly offered their assistance in correcting 

 the ranges. Those who read the greater part of the proof were 

 Outram Bangs, Charles F. Batchelder, Arthur C. Bent, Louis B. 

 Bishop, Allan Brooks, James H. Fleming, Ludlow Griscom, C. E. 

 Hellmayr, Arthur H. Howell, W. L. McAtee, James L. Peters 

 (later a member of the Committee), Harry S. Swarth, P. A. 

 Taverner, and John T. Zimmer (later a member of the Commit- 

 tee). Others who furnished information on certain parts or on 

 certain species were Glover M. Allen, R; M. Anderson, James P. 

 Chapin, Frank M. Chapman, J. Eugene Law, Harrison F. Lewis, 

 John T. Nichols, Robert C. Murphy, George M. Sutton, A. J. 

 van Rossem, and George Willett. Revised sets of the galley 

 proof were examined by some of the Committee and page proof 

 by Dr. Richmond, Dr. Oberholser, Mr. Zimmer, and the chairman. 



The following explanations will make clear the plan of the 

 present edition of the Check-List. 



Scope of the Check-List. After careful consideration the Com- 

 mittee decided to make no change in the area covered by the 

 Check-List. While it has been suggested that Greenland be omit- 

 ted as not being a part of North America and distinctly Old World 

 in its faunal relationship it was felt that nothing would be gained 

 by such action. Greenland would in any case be mentioned in 

 stating the range of a North American species which has oc- 

 curred there, even casually, while most of the Old World species 

 that have strayed to Greenland have also reached some point on 

 the North American continent, so that very few species would 

 be eliminated from the Check-List by such a change in limits. 



It was also considered impracticable to extend the scope of the 

 List to Panama as suggested in the plans for the proposed 

 " Systema Avium " but the present publication may be regarded 

 as the " Systema Avium " for North America north of Mexico. 



So far as time limits are concerned the effort has been made 

 to include all species, subspecies or changes in nomenclature pro- 

 posed up to the close of 1930, but we are aware that some have 

 been omitted entirely, while others have been referred to in foot 

 notes when it was not possible to take action upon them. On 

 the other hand a few cases taken up by the Committee de novo 

 have meanwhile been published during the early part of 193L 



