d44 Correspondence. [April 



With respect to Dr. Grinnell's note, it should be pointed out that in 

 winter when the observations were made, insect life, for the most part, 

 does not "move about again." Hibernating insects are relatively sta- 

 tionary and a considerable part of the insect food available to small birds 

 at this season consists of the eggs and chrysalides of numerous insects, 

 and adult scale insects, which do not change location at all. Further- 

 more, since there is no hard and fast line between non-flocking and flock- 

 ing birds, any sequestration theory is bound to run counter, to the recog- 

 nition-mark and related theories. Indeed, does it not appear that the- 

 ories are best avoided? When facts accumulate sufficiently, their average 

 tendencies, which we are in the habit of calling "natural laws," are ap- 

 parent of themselves. 



W. L. McAtee. 



U. S. Biological Survey, Washington, D. C. 



[In connection with the oft-quoted Bachman-Audubon experiment 

 which Mr. McAtee once more falls back upon, why cannot some of our 

 ornithologists in the Southern States, where Vultures abound, try this 

 experiment over again? We are not usually willing to accept a statement 

 of this sort without corroboration and why should we not have more 

 light upon this matter? — Ed.] 



Ridgway's Birds of North and Middle America, Vol. VIII. 



Editor of 'The Auk': 



In a monumental work such as Ridgway's 'Birds of North and Middle 

 America,' errors are certain, however careful and competent the worker 

 may be. Part VIII of that work has just been received and I hasten to 

 indicate rather an unfortunate mistake so that correction may be at once 

 undertaken. 



On p. 608 appears " Larus affinis Reinhardt, Siberian Gull," and its only 

 claim to inclusion in the work appears to be the record of the type de- 

 scribed from "Nenortalik, Julianehaab, S. Greenland." I have shown 

 that the type was not referable to the Siberian Gull so-called, but was a 

 specimen of the form of Larus fuscus Linne which Lowe had separated 

 under the name L. f. britannicus. This has been accepted by all British 

 ornithologists and the entry in Ridgway's synonymy, p. 609, "Larus 

 fuscus affinis Kennedy, Ibis, Jan. 1917, 31" refers to this fact and not 

 to the "Siberian Gull." Consequently all the matter under the heading 

 "Larus affinis" on pp. 608-609, save that dealing with Reinhardt's speci- 

 men and the one above quoted, must be eliminated as not pertinent to 

 the American fauna. The essential references in confirmation read: 



Lowe, British Birds (Witherby), Vol. VI, No. I, p. 2. June 1, 1912. 



Lowe, Bull. Brit. Orn. Club, Vol. XXIX, p. 119. July 17, 1912. 



