208 Saunders, An Ecological Bird Study. L April 



when another rival male was in the vicinity for a few days. I 

 once observed a similar case of Nighthawks staying in a cotton- 

 wood grove through the breeding season, at Bozeman, Mont., and 

 in that case saw the two young with the parents in August. I was 

 then informed by a person whose information I had usually found 

 to be unreliable, that Nighthawks often laid their eggs in a hollow 

 spot on the upper surface of a horizontal cotton wood limb. Think- 

 ing this might possibly be the case with my Choteau birds, I climbed 

 the trees, and examined the favorite perching places of these birds, 

 but found nothing. There was a curious warfare between these 

 Nighthawks and the Western Wood Pewees inhabiting this grove. 

 The Nighthawks were fond of the same sort of horizontal limbs for 

 perches that the Pewees chose for nesting sites, and whenever a 

 Nighthawk attempted to alight on a limb near one of the Pewee's 

 nests, the male Pewee drove it off with a ferocity that showed his 

 relationship to the Kingbird. 



Because I found certain birds nesting on the area, whose presence 

 was due to the stream which crossed it, I found it best to add 

 another association, the stream border. Perhaps this association 

 could have been more easily figured in terms of length of the stream, 

 but for the sake of uniformity in comparison with the other asso- 

 ciations, I figured it as closely as I could in acres. This association 

 consists mainly of the banks of the stream, a typical prairie stream, 

 with deep pools and shallow rapids but no very swift places. It 

 was bordered by occasional stony bars, and by steep clay banks 

 three or four feet high. The banks were mostly grass grown, but 

 there were a few clumps of young cottonwoods, buffalo berry 

 bushes, and birches (Betula fontinalis). The birds found nesting 

 along the stream border were as follows. 



Total 11 0.45 



The Spotted Sandpipers nested on the stony bars along the edge 

 of the stream, and I located three of the four nests. The Kill- 



