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 Nov., 1911 RELATION OF BIRDS TO AN INSECT OUTBREAK 203 ant about Sisson. Flocks containing hundreds of individuals were often seen feeding on the meadow-land or on the stubble fields. They seemingly paid no at- tention to the hordes of butterflies but busied themselves searching for vegetable food. Stomach examination showed a considerable quantity of oats and other seeds, probably waste picked up in the stubble fields. A very small percentage of the food was made up of small ground beetles and grasshoppers. Most of the Bullock orioles (fclerus bullocki) seen were feeding on huckle- berries or other wild fruit. Eighty-two percent of the food in the stomachs ex- amined was made up of wild fruit, mostly huckleberries and elderberries. The only animal food found consisted of wild bees. The commonest sparrows were' English sparrows (Passer domesticus) in town, Brewer sparrows (S2bizella breweri) in the weed patches, and thick-billed fox sparrows (Passerella iliaca megarhyncha) in the brush. The English sparrow appeared to be feeding entirely on weed seeds as did also the Brewer sparrows, The stomachs of three Brewer sparrows were filled with weed seed and a few small beetles. The fox sparrow appeared to be largely a vegetarian also, for 96 percent of the food in two stomachs was composed of weed seeds. Parts of two ground beetles formed the only animal food. The stomach of a mountain song sparrow (JlffeloslSiza melod[amonlana) contained two cutworms, one unidentified larva, one beetle larva, and one small bee. A bird of the brush, the green-tailed towhee (Oreos2biza chlorura), was found to feed largely on small beetles and seeds, for the two stomachs examined were filled with these kinds of food only. Only two species of woodpeckers were available for examination. As most of the members of this family feed very largely on larYae it seems probable that their use as checks would be most noticeable when the larvae were abundant. The one stomach of the woodpecker most likely to feed on the butterfly, the red-shafted flicker (ColasSics caret collaris),' failed to show any 2?ugonia cahfornica. Two flickers, feeding on the ground, were watched for twenty minutes, but they paid no attention to the many butterflies. They walked along searching the ground care- fully for some sort of food, in all probability ants. The stomachs of two white- headed woodpeckers (Xeno2bicus albolarvalus) were filled with vegetable matter, doubtfully identified as fungus, and a few beetles. Blue-fronted jays (Cyanocilla slellerifrontalis) were often seen either climb- ing to the top of a fir or sailing from the tip top of one tall tree to a lower one. Only once was one seen feeding on the ground. Five 2?ugonia californica were found in one of the two stomachs examined. The other contained a number of large green larvae. It seems natural that a bird with the varied diet of the jay should turn to this particular form of insect food when it became available. A western bluebird (Sialia mexicana occidentalis), perched on an old stump in a small grassy pasture, was watched for half an hour. It flew to the ground, caught a white moth, flew back to the stump and proceeded to tear it to pieces and eat it. During the next fifteen minutes it repeated the operation four more times, having within twenty minutes destroyed five moths. Butterflies were very abund- ant, but the bluebird appeared to prefer the smaller moths to the larger butterflies. Two stomachs were available for examination. One contained a number of small beetles and the other two grasshoppers. Large flocks of western robins (Planesticus mzratorius 2bro2binquus) could be found wherever wild fruit was abundant. Especially was this true where huckleberries were common. The flocks were made up largely of juveniles. An examination of thirteen stomachs gave evidence that their food at that particular