378 BULLETIN 197, UNITED STATES NATIONAL MUSEUM 



nuptial molt about the head aud breast, as noted by Ned Dearborn 

 (1907). 



Food.— Frof. F. E. L. Beal (1907) made a study of the western 

 warbling vireo in California, based on the examination of 110 stom- 

 achs, collected during the seven months from April to October, inclu- 

 sive. He writes : 



Insects, with a few spiders, amount to over 97 percent of the diet, leaving less 

 than 3 percent of vegetable matter, practically all of which was taken in August 

 and September; it consisted of wild fruit (elderberries), a few seeds of poison 

 oak, a few other seeds, and some rubbish. 



Of the animal food the largest item is Lepidoptera ; that is, caterpillars, moths, 

 and the like. These amount to something more than 43 percent of the whole. 

 Caterpillars make up the great bulk of this portion of the food and are a very 

 constant and regular article of diet. * * * In April they amount to over 

 82 percent of the food of the month. Pupae of coddling moths were identified 

 in four stomachs. * * * 



Hemiptera are the next most important item of diet, and amount to 21 percent. 

 They consist of stink-bugs, leaf-bugs, leaf-hoppers, spittle-insects, tree-hoppers, 

 and scales. The last were the black olive species (Saissetia oleae). Cocciuellid 

 beetles, or ladybirds, were eaten to the extent of over 19 percent of the whole. 

 "' * * Other beetles, mostly harmful species, amount to more than 7 percent. 



Hymenoptera, consisting of a few ants and an occasional wasp 

 made up a little more than 1 percent. "A small number of flies, grass- 

 hoppers, and dragon-flies make up a little more than 3 percent of the 

 miscellaneous insects. Spiders were eaten to somewhat less than 2 

 percent." 



Mrs. Wlieelock (1904) says: "In the fall this bird becomes very 

 friendly, coming into the orchards and gardens to hunt busily among 

 the leaves for small caterpillars. At this time he is fond of the cornel 

 berries that grow along the mountain brooks, and occasionally con- 

 descends to eat mistletoe." 



Mr. Rathbun watched a western warbling for a long time while it 

 was busily feeding in some trees, and he says in his notes : "While hunt- 

 ing among the branches and foliage of a tree the vireo sang frequently, 

 and at times the song was given when the bird turned its head from 

 side to side. Often the vireo would poise in the air for an instant to 

 take some insect from beneath a leaf, then begin again its inspection 

 of the twigs and leaves. The bird made this distinction in anything it 

 captured; if the prey was small, it was eaten as soon as taken; but if 

 of large size, it was well minced before being swallowed." 



Voice. — All the habits, except as mentioned above, and the song of 

 the western warbling vireo do not seem to differ from those of its 

 eastern relative. It is an equally persistent singer. Mr. Rathbun 

 says in his notes: "Its warbling song is heard incessantly from the 

 time of its arrival until nearly the middle of June, then much less 

 frequently. I have noticed that in the early part of the season the 

 character of the weather has no effect whatever on its tendency to sing, 



