158 BULLETIN 2 03, UNITED STATES NATIONAL MUSEUM 



mature plumage that were seen. At a very liberal estimate I should 

 say that the males in adult plumage comprised barely a third of the 

 birds seen in the spring." 



Adults have a complete postnuptial molt, mainly in July ; all June 

 birds that I have seen are in worn plumage, and August and Sep- 

 tember birds are in new, fresh feathers. The fall plumage of the 

 male is similar to that of the spring male, but the colors of the head, 

 neck, and chest are duller, more clay color, the back is more olive and 

 the sides are browner. In the female at this season the crown is tipped 

 with grayish and the throat and breast with buflPy, while the sides 

 are browner than in the spring; the white tips of the greater wing 

 coverts are tinged with yellowish. The nuptial plumage is acquired 

 mainly, if not entirely, by wear, the edgings wearing away and the 

 colors becoming brighter. 



Food. — Nothing definite seems to have been recorded on the food 

 of the olive warbler, but its habit of creeping over the branches and 

 twigs of the pines, much after the manner of the pine warbler, would 

 seem to indicate that it was foraging for the many small insects that 

 infest these trees. It is evidently one of the protectors of the pine 

 forests. Brewster (1882b) says: "In their actions these Warblers 

 reminded Mr. Stephens of Dendroeca occidentalis. They spent much 

 of their time at the extremities of the pine branches where they 

 searched among the bunches of needles for insects, with which their 

 stomachs were usually well filled. Occasionally one was seen to pur- 

 sue a falling insect to the ground, where it would alight for a mo- 

 ment before returning to the tree above." 



Behavior. — One of the members of Henshaw's (1875) party 

 brought in a specimen of this warbler, on September 20, "which he 

 stated he had shot from among a flock of Audubon's Warblers and 

 Snowbirds, which he had started from the ground while walking the 

 pine woods. With the rest, it had apparently been feeding upon the 

 ground, and had flown up to a low branch of a pine, where it sat 

 and began to give forth a very beautiful song, which he described 

 as consisting of detached, melodious, whistling notes." 



W. E. D. Scott (1885), writing of his field work in the Santa 

 Catalina Mountains in late November, says : 



Associated with flocks of the Mexican Bluebird (Sialia mexicana), which 

 was, by the way, the only kind of Bluebird observed, was always to be found 

 one and sometimes two representatives of the Olive Warbler {Peucedramus 

 olivaceus). The Bluebirds were generally feeding on some insects in the tall 

 pines, in flocks of from six to ten individuals. The Olive Warblers were on the 

 best of terms with their blue friends, and as the Bluebirds were shy and restless 

 they made it difficult to obtain or observe very closely their smaller allies, I 

 did not in these pine woods see the two species apart, and became at length 

 so well aware of the intimacy that existed between them, that I would fire at 



