Page:Condor11(4).djvu/3

 THE. C91B.R Volume XI July-August 1909 Number AN ANNOTATED LIST OF THE BIRDS OF THE BARR LAKE DIS- TRICT, ADAMS COUNTY, COLORADO* By L. J. HERSEY and ROBERT B. ROCKWELL WITH SIX PHOTOS BY THE AUTHORS N submitting the following annotated Hst of the birds of the Barr Lake district, the writers fully realize that it is not a complete list of the species which occur in that section. There have been omitted a number of speeies that without reasonable doubt occur there, because of lack of absolute identification. Most of the birds included in the list have been taken and identified, and the few that have been included without specimens being taken are birds of positive identification- marks like the LarksBunting and Black-necked Stilt, not easy to mistake. For want of natural boundaries, the "Barr Lake district" as here treated, is a circular area fifteen miles in diameter, with the station of Barr as a center. This area is located in Adams County, nineteen miles northeast of Denver, in typical prairie country, and twenty-seven miles east of the foothills of the Rocky Mountains and at an altitude of about 5100 feet. The chain of lakes which fur- nishes the material for this list is almost entirely artificial, the two large lakes (which, combined, cover an area of about eleven hundred acres) being artificial irrigation reservoirs, and the long chain of lakes or ponds below, being caused by seepage from the main reservoirs. The scope of this list has been arbitrarily determined, and of sufficient size to include a portion of the valley of the South Platte River, the principal stream of northeastern Colorado, and a portion of Box Elder Creek, a typical prairie stream, draining the territory east and south of Barr, and emptying into the Platte. This we did to enable us to include in our list several species of birds, typical of wooded areas and not found in treeless sections, as for example the Rocky Mountain Screech Owl and the Brown Thrasher. The point of greatest interest in this list, to the bird student, will perhaps be the avifaunal changes that have taken place as the result of changed environmental conditions. Twenty-one years ago this entire district was covered with sage-brush, cactus and gramma grass, and was good hunting ground for antelope. Probably
 * An advance print of 100 copies of this article under special cover was issued from Santa Clara, June 28, 1909.