28 BIRDS OF CALIFORNIA AFFECTING FRUIT INDUSTRY. 



as insect destroyers. They do not consume any product of hus- 

 bandry, and the worst that can be said of them is that they eat some 

 useful insects with the harmful ones, though the former are in a 

 very decided minority. This statement, however, applies to any and 

 all insect-eating birds. It would be just as reasonable to expect a 

 mower or reaper to cut grain and leave the weeds standing as to sup- 

 pose that from the hordes of insects around us birds will select only 

 the ones that are injurious to man and leave untouched those that ang.-. 

 beneficial. Then, too, a superabundance of any species of insects. 

 even beneficial ones, would be a nuisance. The service which swal- 

 lows render is to prey upon the whole insect tribe and so to reduce 

 the flood of insect life to a lower level where it may be more easily 

 dealt with by man. 



CLIFF SWALLOW. 



(Petrochelidon lunifrons.) 



In the Eastern States the cliff swallow has practically abandoned 

 its original nesting sites under cliffs, and now nests under the eaves 

 of houses and other buildings. The writer has counted 80 nests 

 beneath the eaves of 1 barn. In California the bird has taken up 

 with the new order of things to some extent, but has not entirely 

 abandoned its old habits. It is a migrant and remains in the State 

 for about six months only during the breeding season, which is the 

 time when the bird does the most good. 



The following discussion of the food of the cliff swallow is based 

 upon the examination of 123 stomachs, representing every month 

 from April to September, inclusive. 



Vegetable food. — Vegetable food to the extent of 0.32 of 1 percent 

 was found. In most cases this was simply rubbish taken acciden- 

 tally, though it includes a few small seeds. 



Animal food. — Of the animal matter the largest item is Hymenop- 

 tera. These insects formed over 39 percent of the total food; most 

 of them were bees and wasps, and small parasitic species were identi- 

 fied in a number of stomachs; a few were ants. Unfortunately, 

 many parasitic insects are eaten by birds that take their pre}^ upon 

 the wing, such as swallows and flycatchers. The fact is to be 

 deplored, but in most cases the percentage is not large. Perhaps the 

 most interesting insect among Hymenoptera eaten is the common 

 honey-bee (Ajns mellifera). Of these, 34 were identified, all con- 

 tained in 11 stomachs, in one of which were 8 individuals. All were 

 drones — that is, males. Not a trace of a worker bee was found. In 

 two stomachs drones constituted the whole food and in several others 

 the principal part. It is probable that most of them were taken 

 when the queen made her marriage flight. So far as the writer has 



