322 The Wilson Bulletin — Xo. 91 



servations within this than in any other South Dakota county. 

 The first to carry on bird studies in this area was F .V. Hay- 

 den, the eminent geologist, who cohected many birds " near 

 the mouth of the Vermilion River "' in jMay and June. 1854 

 and 1855. His records are included in Elliot Coues' classic 

 "Birds of the Northwest" (Washington, 1872). C. S. Ag- 

 ersborg, in " The Auk " for 1885 gives a list of the birds 

 of Southeastern Dakota. Of the 215 species included, most 

 were observed in the vicinity of Vermilion, in or near which 

 city Air. Agersborg had lived for several years. During the 

 past ten years, three students of the University of South Da- 

 kota have made some study of the birds. Benjamin Rowley 

 and E. H. Sweet deserve special mention. Sheridan Jones 

 also collected and mounted some specimens for the University 

 Aluseum, but left no other record of his work. 



The following list has been compiled in part from data 

 furnished me by Rowley and Sweet, from Agersborg's arti- 

 ticle, and Hayden's records, but it is chiefly the result of my 

 observations in the area since 1908, especially 1910-13, while 

 a member of the faculty of the University. With the help 

 of a motorcycle, the more favored localities could be visited 

 frec[uently, and much more effective work was possible than 

 in the case of less fortunate observers. Careful records of 

 the migration, abundance, and nesting' of the birds seen were 

 made for the U. S. Biological Survey, and numerous speci- 

 mens were collected- for the Universit}^ Aluseum. 



Clay County can be divided into five districts: (1) The 

 Missouri bottom land: (2) The valley of the \"ermilion 

 River; (3) The blulTs along these valleys, the ravines of 

 which are especially distinctive: (1) The nearly level upland 

 or " prairie "; (5) The rough land of the northeastern corner 

 of the county. 



Most of the area is under cultivation. The chief exceptions 

 are sand areas- in the Alissouri bottom, flooded areas (now 

 however extensively drained by the recently completed " big 

 ditch " ) in the X'ermilion vallev and the rough land along 

 the blufl's. Tliere are few small ponds on the upland level ; 



