Vol. xxxn 



1914 



] Saunders, An Ecological Bird Study. 201 



the different species in each association, and the actual abundance 

 of each species figured on an acreage basis. In the nesting season 

 of 1912, I found such an opportunity. It was not in the mountain 

 forests as I had hoped it would be, but in the vicinity of the little 

 prairie town of Choteau, in Teton County, Montana. Here, 

 with the exception of a short period from May 28 to June 5, I was 

 confined to office work all through the spring and early summer, 

 until August 5, when I finally left for a trip to the mountains. 

 During this time I had my early mornings, evenings, Sundays and 

 holidays free to explore the country in the immediate vicinity of 

 Choteau, in search of birds and birds' nests. 



On the southeast side of Choteau was an area, watered by a 

 small stream known as Spring Creek, which I found to be an ex- 

 cellent place for birds. While I often explored other areas in the 

 vicinity, I found this one to be the most accessible, and was on it 

 almost daily throughout the spring and summer. Early in June, 

 after most of the migration was over and when the nesting season 

 for most species was just beginning, I decided to make an ecological 

 study here. I blocked out, roughly, a rectangular area, which by 

 later measurements I found to be about 1400 by 8250 feet, and to 

 contain about 265 acres. On this area I started to determine as 

 closely as I could, the actual number of birds of each species, 

 breeding in each association. I could not very well hope to find all 

 the nests, particularly of the ground nesting birds, but I found that 

 I could get my numbers accurately by noting the number of male 

 birds of a species in song. I found that during the period of early 

 morning song, practically ever male bird was participating. By go- 

 ing over the area carefully each morning, and noting the numbers 

 of birds of each species that were in song I soon had my census of 

 the singing birds. The non-singing birds were most of them 

 conspicuous for other reasons and easily found. It is possible that 

 I may have missed a few birds that nested on the area. A Sharp- 

 tailed Grouse might have had its nest in the cinquefoil brush, as 

 several did in similar places outside the area. A Sora could have 

 nested in one of the cattail sloughs and escaped my notice. It is 

 also possible that there were more nests of the Mallard on the area 

 than I found. With these exceptions I am quite certain that I 

 counted all the nesting birds on the area. Of course I repeatedly 



