50 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY. 



the highest order, it does not so directly affect the interests of horti- 

 culture as it would if it frequented orchards and gardens. It may be 

 said, however, that as the swamps and thickets in which it lives are 

 the recruiting grounds for many orchard pests, the bird that destroys 

 them in their native haunt; s is by no means without economic value. 



In a somewhat restricted investigation of the food of this bird 114 

 stomachs, taken in every month except January, were examined. 



Vegetable food. — A few seeds and bits of rubbish is the sum total of 

 the vegetable food, and it is probable that these were taken accident- 

 ally. Some of the ants of California store up seeds, and when snap- 

 ping up ants the yellowthroat probably takes the seeds along with 

 them. 



Animal matter. — The animal matter amounted to 99.8 percent of 

 the total food. The largest item is Hymenoptera, amounting to 35 

 percent, of which about half is ants and the remainder wild bees, 

 wasps, etc. 



Hemiptera amount to 28 percent, and are made up of leaf -bugs, 

 leaf-hoppers, tree-hoppers, plant-lice, scales, and probably some others 

 not identifiable. The black olive scale was found in a few stomachs 

 and plant-lice in one, but the other families were a pretty constant 

 component of the food in every month. 



Beetles were eaten to the extent of nearly 15 percent, and are mostly 

 harmful species, the exception being a few coccinellids of the genus 

 Scymnus, which, however, do not amount to 1 percent of the whole. 

 Weevils and others of the more common families make up the rest of 

 this portion of the diet. The three orders of insects mentioned above 

 form the great bulk of the food of the yellowthroat, and are regularly 

 eaten throughout the year. 



Caterpillars and moths comprise 5 percent, but, so far as the 

 stomachs at hand show, are eaten very irregularly and do not appear 

 on the preferred list. The same may be said of Diptera, though they 

 amount to 12 percent, but in several months none were eaten. Grass- 

 hoppers were found in only four stomachs, but one of these contained 

 nothing else. Spiders are taken to the extent of nearly 4 percent, but 

 in some months none were found and only a trace in others. 



SUM M AST. 



From the above rather brief survey of the food of the yellowthroat 

 it is evident that the horticulturist has nothing to fear from this 

 bird should it change its habitat and become an inhabitant of 

 orchards and vineyards. It is practically wholly insectivorous, and 

 the insects it eats are either harmful or of little economic value. It 

 eats no fruit or grain, nor,, so far as known, any other useful product. 

 Like other members of the family, its life is passed in unceasing 

 search for insects. 



