SUMMARY OF ROSEBREASt's POOD HABITS. 57 



were only four visits made by a parent bird when but one insect was fed to the 

 young; they usually brought three or more. A bird often carries in this way 

 from three to eleven or twelve small caterpillars in its mouth and beak at one 

 time. Owing to the height of the nest above the ground, it^was impossible to 

 determine accurately the species of caterpillars brought to the young. A con- 

 siderable portion of them were certainly leaf-rollers from the oak trees. It 

 seems probable, then, that these two birds must have fed their young on that 

 day at least 1,000 insects, mostly caterpillars. This certainly is a very moderate 

 estimate of the number of insects destroyed in one day by the family when we 

 take into consideration the food required by the old birds.** 



Although in this particular instance the precise nature of the food 

 was not ascertained, there is much evidence to show that the same 

 pests are fed to the young which are eaten by adults. 



Summary. 



Examinations of 176 stomachs of rose-breasted grosbeaks show 

 that the food is composed of animal and vegetable matter in almost 

 equal parts, the exact proportions being 52 and 48 percent, respec- 

 tively. Of the portion of the diet gleaned from the plant kingdom, 

 5.09 percent is grain, 1.37 garden peas, and 19.3 wild fruit. • A third 

 of the grain eaten may possibly be pillaged from standing crops, 

 but this is the only stage when injury by birds is not easily pre- 

 vented. Even if the total amount of grain consumed is pilfered 

 from* cultivated fields, it does not warrant hostile acts against a bird 

 otherwise so beneficial. 



Wild fruit is greatly relished, but cultivated fruit is not damaged, 

 and although budding is practiced to a certain degree practically no 

 harm results. 



The rosebreast preys to some extent upon such beneficial insects as 

 parasitic Hymenoptera, ground beetles, ladybirds, and fireflies. 

 Only a tenth of the animal food is of this character, however, while 

 among the remaining nine-tenths, which consists almost exclusively 

 of injurious insects, is included a large number of formidable pests. 

 Among these are -the cucumber beetles, the hickory borer, plum cur- 

 culio, Colorado potato beetle, Rocky Mountain locust, spring and 

 fall cankerworms, orchard and forest tent-caterpillars, tussock moth, 

 army worm, gipsy and brown-tailed moths, and the chinch bug. The 

 bird is known as an active enemy of the cankerworm and the army 

 worm during their extraordinary infestations, and was among the 

 birds which preyed upon the Rocky Mountain locust and the gipsy 

 moth at the height of their destructiveness. 



Few birds have so good record both as to -the large number of 

 important pests attacked and the slight amount of damage done. 



a Forty-seventh Annual Report Mass. State Board of Agriculture (1899) 3901, 

 p. 325= 



