VOl i906' 111 ] Recent Literature. Ill 



RECENT LITERATURE. 



Stejneger s ' The Birds of the Genus Cinclus and their Geographi- 

 cal Distribution.' — In this paper of ten pages 1 Dr. Stejneger con- 

 siders the affinities, probable place of origin, and the geographical 

 distributions of the Dippers — an oscinine type modified to assume the 

 role of an aquatic bird, and hence presenting puzzling relationships. 

 "Even at this late day there is no absolute certainty as to their most 

 intimate relationships. . . .The majority of ornithologists of to-day divide 

 upon the question whether the dipper is more closely allied to the thrushes 

 (Turdida? in the wider sense) or to the wrens." Contrary to his former 

 belief, the author is now "convinced that Cin^us has sprung from the 

 same root" as Sialia and Saxicola, and "that i J s many peculiarities are 

 mere adaptations to its aquatic habits." Furthermore, instead of assign- 

 ing to it a neotropical origin, as he did in 1885, he now "has no hesita- 

 tion in affirming that Cinclus is of palaearctic origin"; or, more definitely, 

 that it originated in " that enormous and ancient plateau and mountain 

 region north of India and east of 90° east longitude .... From this center 

 the dippers radiated wherever high enough mountain ranges, or otherwise 

 boreal conditions, permitted them to push forward their colonies." As 

 they are mountain and torrent loving birds, their distribution is peculiar; 

 they inhabit the high mountain systems of the Palsearctic subregion from 

 the Atlantic to the Pacific, but in the New World "are confined to the 

 boreal zone of the long Cordilleran chain from Alaska to the Argentine 

 Republic," extending in South America eastward to eastern Colombia, 

 but in North America not ranging east of the Rocky Mountain system. 



He would place the origin and beginning of the dispersal of the group 

 " not later than the dawn of the Tertiary"; and assumes that they reached 

 North America from Asia by the land bridge believed by geologists to have 

 existed somewhere about Bering Sea, at about the time of the uplift of the 

 mountain ranges that parallel the pacific coast from Alaska to Patagonia. 

 Although a wide sea is supposed to have existed across what is now Pan- 

 ama during the early Tertiary, a land bridge joined North and South 

 America early enough for the dipper to have "probably gained a foothold 

 in the Andes before the advent of the Pliocene." "The dipper which 

 reached farthest south (Cinclus schulzi) seems to have become most modi- 

 fied, for it has acquired a light rufous throat, a character entirely unique 

 in the genus." 



The place of origin and relative antiquity of the several leading types of 

 the group is further considered, and also the influence upon them of isola- 



'The Birds of the Genus Cinclus and their Geographical Distribution. By 

 Leonhard Stejneger. Smith. Misc. Coll. (Quart. Issue), Vol. XLVII, pp. 421-430, 

 April 5, 1905. 



