° 1914 J Saunders, An Ecological Bird Study. 205 



The nest was not found however. This bird I consider rare and 

 unusual in this association, its proper place being in the willow 

 thicket association, where it is fairly abundant. 



The Mallards on the area should probably not be expressed as 

 pairs. I found two nests of the species, under the cinquefoil 

 bushes, but observed only the female birds, and then only when I 

 flushed them from their nests. These birds evidently fed principally 

 in the sloughs or along the creek. I have never observed the drake 

 Mallard around the nest, and do not believe he is ever found there. 

 I occasionally saw one or two drakes on a slough not far outside of 

 this area, that may or may not have been mated to the ducks 

 nesting on the area. I believe that the ducks left this area entirely 

 with their broods as soon as the eggs hatched. 



The nests belonging to the Marsh Hawks and Short-eared Owls 

 were both found, and a detailed study of each made.^ These birds 

 lived on a much larger area than that included in this study and a 

 correct proportion of their numbers to those of other species could 

 be better obtained by a study of a much larger area, figuring their 

 numbers on the basis of the square mile rather than the acre. 

 They obtained food largely from the grass meadow association, as 

 well as the cinquefoil brush. 



The Cottonwood grove association was even more densely popu- 

 lated with birds than the cinquefoil brush. This association 

 occurs on flat areas along streams, in a soil quite similar to that of 

 the cinquefoil brush association. In fact my observations show 

 that the Cottonwood grove is slowly encroaching upon the cinque- 

 foil brush, the Cottonwood trees seeding in under the shade of the 

 cinquefoils, growing up through them, and ultimately crowding 

 them out. This process forms an interesting ecological succession. 

 The principal tree of the cottonwood groves in this part of Montana 

 is the Narrow-leaved Cottonwood (Populus angustifolia.) It 

 occurs both as grown trees, averaging fifty or sixty feet in height, 

 and as younger trees forming a second layer under the older ones. 

 The ground cover is largely tall shade loving herbs, and occasion- 

 ally thick tangles of vines. The species found in the eighteen acres 

 of this association were as follows. 



• See Condor, Vol. XV. pp. 99 to 104 and 121 to 125. 



