° 1914 ] Rockwell. ANTiWETuoRTS, Birds of Golden, Colorado. 313 



mer bird life had disappeared, and the long mountain winter had 

 begun. During the spring, snow storms and cold wet weather 

 tended to retard bird movements, and a heavy sleet storm occurred 

 as late as May 23 in the mountains. The season, from what we 

 could learn, appeared to be a week later than usual, and the late 

 rains caused unusual growths of vegetation in the mountains. 

 Good weather continued throughout the summer and there was no 

 appreciable amount of cold until the middle of August. Fall 

 migration had ceased by November 7, and practically all the regu- 

 lar winter birds had arrived by that time. 



The total number of trips made to this section was twenty-three, 

 which being distributed uniformly over a period of seven months 

 gave us ample opportunity to make a good representative collec- 

 tion of the birds of the region, with the exception of certain species 

 of rare or unusual occurrence, whose presence might only be de- 

 tected in a period of years, not months. Therefore, this paper 

 is not offered as a complete list of the birds of the section, but 

 rather as a basis for comparison between the distribution of bird 

 life on the plains and in the closely adjacent mountains. A few 

 notes made subsequently in this region are for convenience in- 

 cluded here. 



Summary. 



The field work recorded in this paper was all done in a restricted 

 area along the eastern foothills of the mountains around Golden 

 and Morrison, both in Jefferson County, Colorado. The region 

 covered embraces, in the main, a range of elevation between 5600 

 and 7600 feet giving the zonal variation in bird life usual to similar 

 changes in altitude. 



The work done was so distributed throughout the spring, sum- 

 mer and fall that we were enabled to gain an idea of the distri- 

 bution of the bird life during these seasons, and also to gather 

 considerable data on migrations, spring and fall, and vertical 

 movements to and from the higher altitudes. Twenty-three col- 

 lecting trips were made between March twenty-eighth and Novem- 

 ber fourteenth, so that winter conditions were encountered both 

 at the beginning and at the end of the period. 



