HABITS OP THE ORANGE-CEO WNED WARBLER 229 



of birds is concerned. We may consider, therefore, that this 

 pretty bird, whose very name is suggestive of the topic now 

 under discussion, is virtually a summer resident as well as a 

 migrant in all the mountainous Territories of the West, nesting 

 at certain elevations that afford conditions corresponding to 

 those that it finds down to sea-level in the boreal regions to 

 which some individuals press on in the alluring spring-time. It 

 has been traced to the Yukon Eiver, along which mighty water- 

 course the lamented Keunicott found its nests, which were 

 placed on the ground, generally in clumps of low bushes. The 

 same naturalist observed its nesting about Great Slave Lake 

 in June, and both Dr. Brewer and myself have drawn up our 

 descriptions of the structure and its contained eggs from the 

 material thus furnished. The former notes certain variations 

 in architecture according to locality, uests which he examined 

 from more arctic regions being smaller and more compact, as 

 well as more homogeneous in the materials used, which were 

 chiefly stems of small plants and the finer grasses. As usual 

 in the case of ground-building birds, the nests of the Orange- 

 crown seem large for the size of the birdj they may be built 

 of fibrous bark strips outside, and fine grasses or mosses within, 

 with or without other lining, such as the fur of animals. The 

 eggs, which have been found to be four, five, or six in number, 

 measure about 0.67 in length by 0.50 in greatest diameter ; the 

 color of the shell is white, dotted all over — sometimes pro- 

 fusely, sometimes sparsely — with light reddish-brown, the mark- 

 ing being either evenly distributed over the surface, or, as is 

 oftener the case, more numerous about the larger than toward 

 the other end. 



Within the limits of the Colorado Basin, which is so highly 

 diversified in its surface features and climatic conditions, the 

 Orange-crowned Warbler has the mixed character of both a 

 resident and a migratory species. In the spring, it asceads the 

 mountains to seek a congenial nesting place, even at a height 

 of 11,000 feet; it retreats in the fall from these elevated regions, 

 and becomes more generally dispersed. Ton will find it during 

 the migrations especially in the shrubbery along water-courses, 

 wliere you may recognize it by its apparently uniform yellow- 

 ishness, its sprightly, restless movements, its frequent aerial 

 forays after passing insects, and the sharp, wiry "tsip", the 

 incessant repetition of which expresses the vivacity of its 



