188 BULLETIN 203, UNITED STATES NATIONAL MUSEUM 



which are probably parasitic species, though none were positively identified. 

 * * ♦ Caterpillars, with a few moths, aggregate over 18 percent. 



Beetles form nearly 16 percent of the diet, and embrace about a dozen families, 

 of which the only useful one is that of the ladybirds (Coccinellidae) , which are 

 eaten to a small extent. The great bulk of the beetle food consists of small 

 leaf-beetles (Chrysomelidae) , with some weevils and several others. One stom- 

 ach contained the remains of 52 specimens of Notoxus alamedae, a small beetle 

 living on trees. Bugs (Hemiptera) constitute over 19 percent of the food, and 

 are eaten regularly every month. Most of them consist of leaf -hoppers (Jassi- 

 dae) and other active forms, but the black olive scale appeared in a number of 

 stomachs. Plant-lice were not positively identified, but some stomachs contained 

 a pasty mass, which was probably made up of these insects in an advanced 

 stage of digestion. 



Flies seem to be acceptable to the summer warbler; they are eaten to the 

 extent of nearly 9 percent. Some of them are of the family of the house fly, 

 others are long-legged tipulids, but the greater number were the smaller species 

 commonly known as gnats. A few small soft-bodied Orthoptera (tree-crickets), 

 a dragon-fly, and a few remains not identified, in all about 5 percent, made up 

 the rest of the animal food. 



Only about 2i/^ percent of the food was vegetable matter, made up 

 mainly of fruit pulp in a single stomach, one or two seeds and rubbish. 



Rathbun (MS.) says that this warbler "shows some partiality for 

 feeding on aphids, for we have many times watched it in an orchard 

 carefully scanning the leaves on a tree for this insect." 



All other phases of the life histories of this and the following two 

 subspecies do not seem to differ materially from those of the eastern 

 yellow warbler and need not be repeated here. 



Fall. — According to Rathbun's notes, all the resident, breeding yel- 

 low warblers have departed from Washington "by the latter part of 

 August, and in some seasons we have not heard the bird after the 

 twenty-fifth ; it is one of the few species that sing more or less during 

 all of its sojourn here, and its song in late summer is almost as good 

 as on its arrival in the spring. A break in the movement south of 

 this species seems to occur about August 20 to 25. Then, early in 

 September, the notes of the yellow warbler begin to be heard again. 

 We have the idea that these may be of the Alaska yellow warbler." 



Mrs. Allen writes to me from Berkeley, Calif.: "Breeding birds 

 leave the bay region in late July or early August ; migrants from far- 

 ther north begin to go through in September ; the latest date on which 

 I have seen them is October 16, 1920. I usually see them in the shade 

 trees along the streets or in the woods when they come to bathe in my 

 bird pool. But I have two records which show them in very different 

 situations : September 18, 1933, on a hill slope that had been recently 

 burnt over, a group of these warblers with horned larks and Savannah 

 sparrows ; and on September 25, 1941, at Point Reyes lighthouse, hunt- 

 ing for food in the low, dry lupines just inside the rocky point. One 

 could not help wondering if they had just come to a landing place after 

 a long flight over the ocean. They were in immature plumage." 



