Other items were flies, less than 1 percent, and spiders, 7 percent. W. L. McAtee (1912) says that this is one of only two wood warblers known to prey upon codling moths. "The lutescent warbler shows a strong liking for the pupae, two taken in California in May having eaten 10 and 18 pupae, respectively." _Behavior._--Mrs. Wheelock (1904) writes thus of its feeding activities: "All day long he flits about through the oak trees, leaning 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 leisurely 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 November 1. Taylor and Shaw (1927) write of the fall movement on Mount Rainier as follows: The postnuptial 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: