"iSgs' J Cooke, Summer Ifang-e of Colorado Birds. I C 1 



there are only 60 eastern birds found here, meaning by eastern, 

 those that are generally distributed in the East and extend only 

 to the Rocky Mountains ; while there are 90 species of western 

 birds found here that do not occur to the eastward, in addition 

 to 22 species that are peculiar to the Rocky Mountains, and 

 13 species that reach Colorado from the southwest. The 

 remainder of our State's quota is made up of 16 species from 

 the north, 17 from the south, 2 from the southeast, and 127 

 species that are of general distribution throughout the United 

 States. 



It is not, however, of Colorado bird-life as a whole that it is 

 intended to speak, but of the summer birds. It is at this time 

 of year that the mountainous character of the surface exerts the 

 greatest influence on bird life. This can be shown most easily 

 by a comparison with the prairie States to the eastward. The 

 State list of Kansas numbers 335 species, of which 175 are 

 known to breed in the State. Illinois, from about an equal 

 number of species, shows 205 breeders. This large proportion 

 of nesting species is due to the great extent of Illinois north 

 and south. The same result is reached in Colorado through 

 the effect of the mountains. Out of 347 species known to the 

 State, 236 have been already ascertained to breed within her 

 limits, and it is probable that almost one-half of the remainder 

 will .some day be added to the list of l^reeders. In broad terms 

 it can be stated, that few birds occur in the State at any season 

 of the year that are not also found there in summer. And why 

 should it not be so. In a prairie State, the great bulk of the 

 winter and early spring birds pass on northward to find a cool 

 climate suitable to their nature and inclination. What these 

 birds obtain by a northward journey of a thousand miles, their 

 western cousins in Colorado duplicate by a trip of less than one- 

 twentieth the distance. The everlasting snows lie on about one 

 Iiundred peaks of the Colorado mountains, and in their vicinity 

 the hardiest birds can find congenial summer homes. The con- 

 verse is also true ; each of the widely varied portions of the 

 State, at any and all seasons of the year, is inhabited by a goodly 

 variety of birds. There is a climate for each bird and a bird 

 for each climate. One would expect to find bird-life in May 



