524 KEPORT OF STATE GEOLOGIST. 



PECULIARITIES AFFECTING BIRD DISTRIBUTION. 



The region about the southern end of Lake Michigan presents an 

 unusually fertile field for the ornithologist. Situated as it is, midway 

 between the wooded region of the East and the treeless plains of the 

 West, with the warm river bottoms of the South, rich in southern 

 species, extending to within a comparatively short distance, and the 

 great lake upon the north, northwestern Indiana forms a kind of "'four 

 corners" where the avian faunae of four regions intergrade. To the 

 proximity of Lake Michigan we are indebted for a number of more or 

 less strictly maritime species. As would be expected the southern 

 species occur only in summer, with the exception of Lophophanes 

 tricolor, which is found only in winter. Not only is the influence of 

 the lake upon the faunae shown by the occurrence of numerous species 

 of birds, attracted by the presence of a large body of water, with its 

 congenial surroundings, but the influence of the lake upon the climate 

 and the vegetation in its immediate vicinity has a marked influence 

 upon the list of summer residents. The northwestern portion of the 

 State is divided into alternating tracts of prairie, marsh and wood- 

 land, each possessing a bird life of its own. In Lake County, along 

 the Lake Shore, is a stretch of pine woods known as ''the pinery," 

 which is quite peculiar. (Condensed from E. W. Nelson's notes of 

 "Birds of Northeastern Illinois.") Coming south one crosses the Kan- 

 kakee Eiver and marshes, well-known regions for water fowl and 

 marsh-inhabiting birds, and enters the Wabash Valley. Back from 

 this valley proper we find occasional prairies and extensive meadows, 

 where such prairie-inhabiting forms as Henslow's Sparrows. Yellow- 

 winged Sparrows, Black-throated Buntings and Prairie Larks are ex- 

 pected to be found. The lower Wabash Valley is noted for its 

 extended '"bottom lands" and "cypress swamps," which, for their 

 flora no less than their birds, are of much interest. The amount 

 of bird life here in summer is very much in excess of that in the north- 

 western corner of the State at that season. The difference in the num- 

 ber of birds noted would be readily observed. In the southeastern part 

 of the State the land rises in some places almost 400 feet above the 

 Ohio Eiver within a mile or very little more. On leaving the fertile 

 river bottoms, with their successive terraces, one ascends the steep 

 river hills and soon reaches the wet flats where the drainage is so 

 poor that the water stands upon the surface beneath the oak and beech 

 timber the greater part of the year. There is an intimate relation be- 

 tween the topography and the character of the soil here. There a 



