ADDITIONAL LIST OF BOULDER COUNTY BIRDS III 



became so rare, it is likely that the birds were of the last-named species, 

 which has been already recorded for Boulder County. 



The rapidity with which the white-necked raven has decreased in 

 numbers in the. foothill region is an excellent illustration of the effect 

 of civilization upon the fauna of a newly settled country. It is to be 

 regretted that more work was not done in the preservation of natural- 

 history records while the country was in its original condition, in order 

 that the many changes could be determined. It is hoped that much 

 may yet be done along this line in unsettled portions of the state, by 

 trained workers, capable of making accurate observations. The state 

 should establish a _ natural-history survey under the direction of the 

 University, to carry on this work systematically and effectively, with 

 reliable observers well distributed, working systematically, and co-oper- 

 ating with each other, in order to eliminate the speculation and guess- 

 work which have had so pernicious an influence upon natural history 

 in the past, and even now fill so many of the so-called "nature books" 

 in common use in the graded schools and in American homes. 



The listing of species is but a first step in ornithological investiga- 

 tions, to facilitate the solution of numerous other problems, such as local 

 distribution, summer and winter range, breeding habits, migration, food 

 habits, and so on. 



It must not be supposed that the list of birds of Boulder County is 

 anywhere near complete. It is likely that at least fifty or sixty species 

 will yet be added. Conditions are so diverse that a large list may be 

 expected. The plains area forming the eastern portion of the county, 

 dotted with lakes and crossed by streams of various size, fertile fields 

 alternating with dry mesas, presents to the ornithologist an avifauna 

 in part peculiar to itself. The foothill region is the home of other 

 species rarely found on the plains or among the higher peaks. The 

 snow-clad peaks furnish abiding places for species not found much 

 below timber line. Other species seem able to adapt themselves to a 

 great variety of conditions and may be found from the plains nearly to 

 the top of the range. 



The study of bird migration in this vicinity is complicated by at least 

 one feature not found in more level countries. Many species here, as 



