406 Oberholser, Notes on North American Birds. [£uty 



NOTES ON NORTH AMERICAN BIRDS. 

 VIII. 



BY HARRY C. OBERHOLSER. 



In the present installment 1 of these notes on North American 

 birds there are discussed forms of three species belonging respec- 

 tively to the families Motacillidce, Sylviidce, and Trogloclytidoe. 



Anthus spinoletta rubescens (Tunstall). 



In a comparatively recent publication 2 Dr. Ernst Hartert 

 treated the American Pipit as a subspecies of Anthus spinoletta. 3 

 Only a superficial examination is required to demonstrate that this 

 is the correct view of its relationship. It is distinguishable from 

 Anthus spinoletta spinoletta by its smaller size and by the more 

 deeply ochraceous or cinnamon rufous suffusion on the under 

 surface. So far as measurements are concerned, the difference 

 between these two forms is merely average, since the extremes 

 considerably overlap. Both these birds have a wide range of 

 individual variation in color which manifests itself strikingly in 

 two extreme color phases, one gray, the other deep ochraceous, 

 between which there are all sorts of intermediates. There is also 

 much difference in the amount of streaking on the lower parts, 

 some specimens being almost immaculate, while others are very 

 heavily marked on the breast and sides. This great individual 

 variation so completely and widely overlaps the distinctions 

 between Anthus rubescens and Anthus spinoletta that only on 

 average characters are they separable even as subspecies. It is, 

 therefore, perfectly evident that the former should stand as Anthus 

 spinoletta rubescens (Tunstall). 



1 For previous papers in this series, cf. 'The Auk,' XXXIV, April, 1917, pp. 191-196; 

 XXXIV, July, 1917, pp. 321-329; XXXIV, October, 1917, pp. 465-470; XXXV, January, 

 1918, pp. 62-65; XXXV, April, 1918, pp. 185-187; XXXV, October, 1918, pp. 463-467; 

 XXXVI, January. 1919, pp. 81-85. 



2 Vogel palaarkt. Fauna, Heft III, June, 1905, p. 282. 



3 Alauda Spinoletta Linnaeus, Syst. Nat., ed. 10, I, 175S, p. 166 (Italy). 



