176 The Wilson Bulletin — No. 89 



swamp, for instance to designate a tract of wet land grown up 

 with reeds and coarse grasses, cattails, etc., but without any- 

 conspicuous woody shrubs cw trees as is the case with the bog. 



These habitats are of interest only in their relation to the 

 birds living in them. Some species show decided preferences 

 for one plant association : the golden-crowned kinglet found 

 only in the cedar bog, the junco only in the aspens ; others like 

 the hermit thrush were more generally distributed, being 

 found in the bog, hardwoods, and aspens alike., At the end 

 of June there is quite a large bird population in the asp'ens, 

 but by the middle of August it is very much reduced both in 

 numbers of individuals and of species observed. A half day's 

 jaunt in the aspens the forenoon of July 8 gave me a list of 23 

 species ; two days before a similar trip in the hardwoods gave 

 41 species. On August 7 the number seen on a sunny fore- 

 noon's trip was 6 species ; the next forenoon in the hardwoods 

 my list was 46 species. 



In the list which follows will be found the English names 

 of the species, the habitat preference of each species, the fre- 

 quency, the abundance, and nesting data where any were 

 gathered. Frequency and abundance as here used need a 

 word of explanation. The former term refers to the com- 

 parative frequency with which the species, not the individual, 

 was seen; in this connection I have used three degrees as fol- 

 lows : r or rare=rseen from 1 to 4 times ; c or common=seen 

 from 5 to 20 times; a or abundant=seen more than 20 times. 

 Abundance, on the other hand, applies to the total numbers 

 of individuals of the dififerent species seen during a given 

 period ; in this case the period covers from June 30 to August 

 7, stopping before the fall migration gets any headway to dis- 

 turb our study of midsummer birds. (1) under abundance 

 means that this species stands highest in number of individual 

 birds seen, 227 in our study ; at the other end of the scale of 

 abundance (47) means that only 1 bird of this species was 

 identified. With this explanation it will not be difficult to 

 interpret the data : 



