102 BULLETIN 203, UNITED STATES NATIONAL MUSEUM 



away over the tips of the boughs to investigate a spray of leaves, or 

 stretching up his pretty head to reach a blossom just above him ; now 

 clinging head downward underneath a spray, or hovering under the 

 yellow tassels as a bee hovers beneath a flower." 



Voice. — Samuel F. Rathbun (MS.) gives me his impression of the 

 song of the lutescent warbler as follows : "Its song is a succession of 

 trilling notes on a slightly rising then falling key, the latter more 

 lightly given and faster. There is an apparent ease in this song that 

 is suggestive of airiness, and, although simple in construction, it is 

 pleasing to hear and further bears the stamp of distinctiveness." 



Fall. — The fall migration is southward to southern California, 

 western Mexico, and Guatemala. The movement is apparently lei- 

 surely and quite prolonged, for the earliest birds begin leaving western 

 Washington in August and September, and Theed Pearse gives me 

 two October dates for Vancouver Island, with his latest date Novem- 

 ber 1. Taylor and Shaw (1927) write of the fall movement on Mount 

 Rainier as follows: 



The post-nuptial scatter movement was in full swing by the middle of August. 

 At this time the lutescent warbler was often found in the same flocks with 

 Shufeldt juncos, western golden-crowned kinglets, or chestnut-backed chickadees. 

 It is not unlikely that there is some good reason for this flocking, aside from the 

 companionship involved. The warblers and the juncos, kinglets, or chickadees 

 probably do not compete for food as would one warbler with another of the same 

 species. The individual warbler, attached to a flock of kinglets, let us say, may 

 be the more surely guided to available food. Then, too, differences in alertness 

 of the two or more species concerned may afford greater protection to each than 

 would be the case if they remained separate. 



Robert Ridgway (1877) met with these warblers in large numbers in 

 Nevada : ' 



In the fall, the thickets and lower shrubbery along the streams, particularly 

 those of the lower cafions, would fairly swarm with them during the early por- 

 tion of the mornings, as they busily sought their food, in company with various 

 insectivorous birds, especially the Black-capped Green Warbler (Myiodioctes 

 pusillus) and Swainson's Vireo (Vireosylvia sicainsoni). At such times they 

 uttered frequently their sharp note of chip. The brightly-colored specimens 

 representing H. lutescens were prevalent in the western depression of the Basin, 

 but were not observed eastward of the upper portion of the Valley of the Hum- 

 boldt, nor at any locality during the summer ; and wherever found, were associ- 

 ated with individuals of the other form, which is the only one found breeding on 

 the mountains. It is therefore inferred that all these individuals were migrants 

 from the northern Pacific Coast region and the Sierra Nevada, while those of 

 H. celata proper were from the higher portions of the more eastern mountains, 

 or from farther northward in the Rocky Mountain ranges, full-fledged young 

 birds being numerous in the high aspen woods of the Wahsatch Mountains in 

 July and August 



