64 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY. 



pests in the very places where their mischief is clone. This can not 

 be asserted of the marsh wren, but it must be remembered that many 

 harmful species of insects breed and live in marshes and waste places 

 as well as in grainfields and orchards, so that the birds which 

 destroy them on wild lands are removing the source of supply from 

 which are recruited the hosts that infest the farm. 



CACTUS WREN. 



(Heleodytes prunneicapillus.) 

 (PL IV.) 



The cactus wren is so exclusively a bird of the desert and waste 

 places that its food may be thought to have little, if any, economic 

 interest. It is not safe to assume, however, that the bird will never 

 affect the interests of agriculture because it does not do so at present. 

 Moreover, its food habits have a scientific interest which justifies a 

 brief review. A number of the birds whose stomachs have been 

 examined for this work were taken near orchards and grainfields, 

 and there can be little doubt that, with the spread of cultivation, the 

 species will adapt itself to a somewhat different environment and 

 become of economic importance. We find, in fact, that its food is 

 made up of practically the same orders and families of insects that 

 compose the diet of birds living on agricultural lands, but the relative 

 proportions differ widely, and in most cases the species are probably 

 different. 



Only 41 stomachs of the cactus wren were available for examina- 

 tion. They were taken in the region from Los Angeles to San Ber- 

 nardino, and from July to January, inclusive. They contained about 

 83 percent of animal matter to 1.7 of vegetable. 



Animal food. — Beetles and Hymenoptera, the latter ants and 

 wasps, were the two most important items of the animal food. Each 

 made up about 27 percent of the total. The beetles belong to several 

 families, but weevils, or snout-beetles, were the most noticeable, and 

 amount to somewhat more than 10 percent. One stomach contained 

 11 of these insects and another 10, while others held fewer, Only 

 one species, RMgopsis effracta, was identified. Five of these were in 

 1 stomach. The other beetles belong, to more .common families., 

 Coccinellids were found in 1 stomach and carrion beetles ~ni I!." 

 They were the only insects noted that can be considered as useful 

 Hymenoptera are represented by many ants and a few wasps. These 

 are just the insects which the cactus wren might be expected to find, 

 for dry land and sunshine are the conditions which favor these crea- 

 tures. Grasshoppers amount to a little more than 15 percent. This 



