ANDERSON— THE BIRDS OF IOWA. 143 



The geographical position of the State of Iowa, near the center 

 of the United States, and of the great Mississippi Valley, causes its 

 bird fauna to be rich in number of species, and its life zones diffi- 

 cult to map definitely. Its cold winters bring many Boreal visit- 

 ors from the north, and the hot summer attracts many species 

 which are distinctly southern. Thus the Mockingbird, a typical 

 Lower Austral form, frequently reaches southern Iowa, the Pro- 

 thonotary Warbler follows the Missi-ssippi bottoms for some dis- 

 tance past the Minnesota line^ and has been taken in the Des 

 Moines River valley as far north as Algona. Iowa is also near 

 the border line where the eastern varieties of many common birds 

 begin to shade off into the western forms. The occurrence of the 

 Burrowing Owl and Lark Bunting on the prairies of northwestern 

 Iowa is indicative of a close connection with the tj-pical fauna of 

 the Great Plains. Reports from a number of observers indicate 

 that the Cardinal Grosbeak has extended its range considerably 

 to the northward in Iowa during the past few years, while proofs 

 are not lacking that numerous woodland birds have become com- 

 mon in northwestern Iowa within the past twenty years, during 

 which time that part of the state has been rapidl}- settled, and its 

 surface modified by the planting of groves. The Cape May War- 

 bler is believed to have extended its common range well westward 

 into Iowa within the past twenty-five years, while the Western 

 Meadowlark has in the same time .spread over nearly the entire 

 eastern part of the state. 



The intermediate character of the Iowa bird fauna may be indi- 

 cated by a comparison between two recent standard field text- 

 books on the birds of the eastern and western United States 

 respectively: 



Chapman's Handbook of the Birds of Eastern North America- 

 omits the following twenty-one species, all of which have been 

 taken in Iowa: Western and American liared Grebes, Harris 

 Hawk, Western Redtail, Mexican Goshawk, Richardson Merliri, 

 Burrowing Owl, Northern Hairy Woodpecker, Western Night- 

 hawk, Sennett Nighthawk, Magpie, Clarke Nutcracker, Gray- 



1. Roberts, Auk, xvi, 1899, pp. 236-246. 



2. Handbook of Birds of Eastern Nortli America, with keys to the species and 

 descriptions of their plumage, nests and eggs, their distribution and migrations and a 

 brief account of their haunts and habits, with introductory chapters on the study of 

 ornithology, etc., by Frank M. Chapman, Assistant Curator of the Department of Mam- 

 malogy and Ornithology in the American Museum of Natural History, New York City, 

 etc. New York. 1903. 



