Book Description

Excerpt from The Birds of Colorado The following paper is designed to set forth our present knowledge of the distribution and migration of Colorado birds. There is also included a bibliography of the subject and an historical review of the progress of ornithological investigation in this State. The total number of species and varieties of birds known to occur in Colorado is 360, of which 328 are known to breed. This is a larger number of species than has been taken in any state east of the Mississippi and is exceeded by only one state of the Union, that is by Nebraska with nearly four hundred species. The reason for this great variety of bird life is found in the geographical position of the State and the physical characteristics of its surface. From the Atlantic Ocean to western Iowa but slight changes occur in the avi-fauna. But with the decreased rainfall and the increase in altitude from there westward, a great number of new forms appear. The greatest change is at the eastern foothills of the Rocky Mountains, which is the natural dividing line between the eastern and middle provinces of the United States. But while many of the western forms extend as stragglers eastward into Kansas and Nebraska and especially into the Black Hills of South Dakota and northwestern Nebraska, a large number of eastern forms do not pass west of the semi-arid region of twenty inches of annual rainfall and are not found in Colorado. It is due to this fact that Nebraska exceeds Colorado in the number of species taken in the State. All of the eastern species reach Nebraska and nearly all the western forms extend into northwestern Nebraska. This is strikingly shown in the case of the Warblers. Nebraska has more than twenty Warblers that do not occur in Colorado, while Colorado has less than five that are not found in Nebraska. The avi-fauna of Colorado is reinforced by species that belong more properly to the regions on all sides of it. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.