44 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY. 



species, and may be considered as typical of the genus, especially in 

 the matter of food. In the winter season it is a frequenter of 

 orchards, gardens, and dooryards where it pursues its business of 

 insect hunting with a persistent assiduity worthy of all praise. At 

 this season it is very familiar and easily approached. 



In investigating the food of the Audubon warbler 383 stomachs 

 have been examined. The}^ were taken from July to May inclusive. 

 Geographically they are distributed from the San Francisco Ba} T 

 region southward to San Bernardino, and probably give a fair idea 

 of the winter diet of this bird in California. The food consisted of 

 nearly 85 percent of animal matter (insects and spiders) and a little 

 more than 15 percent of vegetable. 



Animal food. — The largest item of animal food is Hymenoptera — 

 wasps and ants — which aggregate a little more than 26 percent of the 

 whole. By far the greater number of these are ants, and as plant- 

 lice also are eaten to a considerable extent, it is probable that many 

 of the ants are species that take care of the lice. The other members 

 of this order are mostly rapid fliers, so the inference is that they were 

 caught on the wing. The greater number were eaten in the fall and 

 spring months. In our record May appears as the month of least 

 consumption — 6 percent. August is the month of greatest consump- 

 tion — 61 percent. This record, however, probably is unreliable, as 

 but one stomach was taken in this month. A few were identified as 

 belonging to parasitic species. 



Flies (Diptera) are represented in the stomachs of the Audubon 

 warbler to the extent of a little more than 16 percent, or one-sixth of 

 the whole food. This is one of the largest, if not the very largest, 

 record of this order of insects eaten by any bird except some of the 

 swallows. Even the so-called flycatchers do not eat so many flies as 

 this warbler — in fact, the name ' wasp-catchers ' would be much more 

 appropriate for that family. The flies eaten by the Audubon war- 

 bler must have been caught in mid-air, for flies as a rule do not allow 

 themselves to be captured without at least attempting to escape. 

 These insects are so soft -bodied that it is not often possible to deter- 

 mine more about them than that they are Diptera. Two families 

 were identified — Muscida?, the family of the common house fly, and 

 Tipulida?, or crane-flies, the long-legged mosquito-like creatures other- 

 wise known as " daddy-long-legs." Most of the Diptera, however, 

 are the smaller species, such as gnats, which fly in swarms, and being 

 rather sluggish are more easily captured. They are eaten with 

 remarkable regularity during the whole season, with no decided de- 

 crease in the winter months — in fact, more were eaten in January 

 than in either September or April. March is the month of maximum 

 consumption, when Diptera constitute over 54 per cent of the whole 

 food. 



