96 BULLETIN 191, UNITED STATES NATIONAL MUSEUM 



Food. — Prof. F. E. L. Beal (1910) examined 326 stomachs of the 

 California jay, and found that 27 percent of the food consisted of animal 

 matter and 72) percent vegetable, though the animal matter amoimted to 

 70 percent in April. Among the insect food, he lists predaceous ground 

 beetles, mostly beneficial species, 2.5 percent for the year and as much 

 as 10 percent in April ; other beetles, mostly harmful, 8 percent for the 

 year and 31 percent in April ; wasps, bees, and ants amounted to less 

 than 5 percent; honey bees were found in 9 stomachs, and all, 20 in 

 number, were workers ; Lepidoptera, mainly in the caterpillar stage, 

 amounted to 2.5 percent; this item included 12 pupae of the coddling 

 moth, an unexpected service that would cover a multitude of sins in other 

 directions ; grasshoppers and crickets were eaten to the extent of 4.5 

 percent. Of other animal food, he says: "A few miscellaneous 

 creatures, such as raphidians, spiders, snails, etc., form less than one- 

 half of 1 percent of the food. * * * Besides the insects and other 

 invertebrates already discussed, the jay eats some vertebrates. The 

 remains consisted of bones or feathers of birds in 8 stomachs, egg- 

 shells in 38, bones of small mammals (mice and shrews) in 11, and 

 hones of reptiles and batrachians in 13 stomachs." In destroying 

 small mammals the jay does good service, as most of them are in- 

 jurious, but the same cannot be said about its appetite for the useful 

 reptiles and batrachians. The damage to the eggs and young of 

 small birds is a serious matter. Some 95 stomachs were collected 

 between the middle of May and the middle of July, the height of 

 the nesting season, "of which 17, or 18 percent, contained eggs or 

 remains of young birds. If we may infer, as seems reasonable, that 

 18 percent of the California jays rob birds' nests every day during 

 the nesting season, then we must admit that the jays are a tremen- 

 dous factor in preventing the increase of our common birds. Mr. 

 Joseph Grinnell, of Pasadena, after careful observation, estimates 

 the number of this species in California at about 126,000. This is 

 probably a low estimate. If 18 percent of this number, or 22,680 

 jays, each robs a nest of eggs or young daily for a period of sixty 

 days from the middle of May to the middle of July, the total number 

 of nests destroyed in California by this one species every year is 

 1,360,800." 



Mr. Dawson (1923) draws a still blacker picture; he figures, on the 

 basis of suitable acreage and average population per acre, that there are 

 499,136 pairs of California jays in the State and says: "If we allow only 

 one set of eggs or nest of birds to each pair of jays per diem for a 

 period of two months, we shall be well within the mark of actuality. Yet 

 that will give us in a season a total destruction of 29,948,160 nests, or. 



