HABITS OF WILSON'S BLACKCAP 329 



of these trees so common in Labrador. It was composed of dry 

 moss and delicate pine twigs " agglutinated" together and to 

 the support from which it was suspended, and was lined with 

 " extremely fine and transparent fibres". It measured not over 

 3J inches in greatest diameter, with a depth of not more than 

 1J inches. The eggs were four, "dull white, sprinkled with 

 reddish and brown dots towards the larger end, where the mark- 

 ings form a circle, leaving the extremity plain". NuttalFs 

 Oregon nest, which contained four fresh eggs on the 16th of 

 May, though fully-fledged young had already been observed, 

 was laid on a bunch of Usnea on the branch of a small service- 

 bush, and was built chiefly of Hypnum moss, with a lining of 

 slender grasses. It will be observed that these accounts do not 

 tally well, leaving room for conjecture whether both, if either, 

 really refer to the present species. Dr. Brewer mentions, but 

 does not describe, a nest obtained on the Yukon River, May 20, 

 containing four eggs, ranging from 0.60 to 0.63 in length by 0.45 

 to 0.49 in breadth, pure white in ground-color, finely sprinkled 

 round the larger end with brownish-red and lilac; and sur- 

 mises by logical induction, from what premises I know not, that 

 this bird builds upon the ground. 



The case of Blackcap's migrations and nestlings is very dif- 

 ferent in the West, where range after range of lofty mountains 

 invites a southerly summer residence, in the selection of which 

 altitude answers to latitude. The bird certainly breeds in the 

 mountains of Colorado, and probably does so in those of New 

 Mexico, Arizona, and corresponding portions of California. For 

 Mr. J. A. Allen found it in summer in the first-mentioned State, 

 in alpine and subalpine districts, from an altitude of about 

 8,000 feet to beyond timber-line, "evidently breeding", though 

 he failed to discover its nest. In the dwarfed willows and other 

 shrubs that extend above the limit of trees, it was found to be 

 the most numerous by far of all the small insectivorous birds; 

 and the alpine character thus exhibited by the species accords 

 completely with the known facts of its summer distribution 

 elsewhere. In Nevada or Utah, Mr. Eidgway found the bird 

 common "during the summer" in the canons of the higher 

 ranges ; and in September it was one of the most abundant of 

 the Sylvicolidce in the East Hum bold t Mountains and in Ruby 

 Valley, without regard to altitude. In the mountains of Ari- 

 zona, at the altitude of Fort Whipple, I found it to be a common 

 summer resident, arriving early in May and remaining through 

 part of September ; but I was no more fortunate than Allen 



