NOTES ON THE WEENS OF THE GENUS NANNUS 



BILLBEKG. 



By Harky C. Oberiiolser, 

 Of the Biological Survey, United States Department of Agricxilture. 



The wrens of the genus Nannus^ from the standpoint of geographic 

 distribution, form one of the most interesting groups of passerine 

 birds. The present contribution to their elucidation is the result of 

 an attempt to identify the specimens of this genus from Alaska con- 

 tained in the collection of the Biological Survey in the United States 

 National Museum. It finally became necessary to extend the investi- 

 gation to most of the Old World forms as well as to all those from 

 North America. For this purpose there have been available the 

 specimens in the United States National Museum, including the 

 collection of the Biological Survey, and a number of others kindly 

 loaned by Mr. John E. Thayer, Mr. Outram Bangs, and Mr. A. C. 

 Bent, to whom for this courtesy the writer wishes to extend his 

 thanks. This material comprises 364 birds, including representa- 

 tives of all the North American forms and most of those inhabiting 

 the Old World, as well as the types of all the North American races 

 excepting iVannw5 hiemalis (Vieillot). 



The most important previous publications on this group are as 

 follows : 



Sharpe, R. Bowdler. — [Genus] Anorthnra. Catalogue of the Birds in the 

 British Museum, vol. 6, 1881, pp. 268-280, pi. 16. 



Oberholseb, Harry C. — Synopsis of the Genus commonly called Anorthura. 

 Auk, vol. 19, No. 2, April, 1902, pp. 175-181. 



RiDGWAY, Robert. — Genus Olhiorchilus Oherholsor. Bulletin of the Uuitod 

 States National Museum, No. 50, pt. 3, 1904. pp. .595-605. 



Hartert, Ernst. — Gattung Troglodytes Vieill. Vogel der paliiarktischen 

 Fauna, vol. 1, Heft VI, June, 1910, pp. 776-784. 



All measurements in the follov/ing pages are given in millimeters, 

 and have been taken as explained in the writer's paper on Butorides 

 virescens} In this connection it might be well to mention that, by 

 an unfortunate mistake, the mensurements of the culmen given by 



1 1'roc. U. S. Nat. Mus.. vol. 42, August 29, 1912, p. .533. 



Proceedings U. s. natjonal Museum, Vol. 55— No. 2265. 



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