206 



Total 



34 



0.53 



These figures show that the Robin is by far the most abundant 

 bird of this association. I believe that my count of this species 

 on the area is absolutely correct, for not only did I find the eight 

 male birds, singing in their respective corners of the Cottonwood 

 grove each morning, but I also observed all eight of the females 

 regularly, and found all of the eight nests. The Robin may have 

 been a little more abundant on this particular area than it usually 

 is in this habitat, but my observations in other places go to show 

 that it is regularly the most abundant nesting bird of the cotton- 

 wood groves in all parts of Montana that I have visited. 



The Magpie is an earlier nester than any of the other species. 

 Its nests were easily found because of their bulk and conspicuous- 

 ness and as all four were thus found, there is no doubt about the 

 count being correct. These birds, however, left the area, after 

 the nesting was over, which was before most of the other species 

 were nesting. If they had not done so, perhaps the other species 

 would not have nested so abundantly. 



The next three species were all easily found because of the sing- 

 ing of the male birds, and I have little doubt about the correctness 

 of the count. I found two nests of the Yellow Warbler, two of 



