204 STATE HOKTICULTUKAL SOCIETY. 



made of the uses of birds in an orchard which was suffering from the canker 

 worm ; and I therefore give you a summary of the facts noted there. Birds 

 were found extraordinarily abundant there, both in species and individuals, 

 although the period of migration had passed. During a single day thirty-one 

 species were observed in this orchard of sixteen acres, and fifty-five birds, rep- 

 resenting twenty-five of the species, were shot for an examination of the con- 

 tents of their stomachs, A careful study of these showed that fifteen of the 

 species and thirty-five of the birds were eating the canker worms, and that 

 these made about forty-five per cent of the food of the whole group of birds 

 shot. The most useful bird was the " cedar bird," about thirty of which had 

 apparently taken up their residence in the orchard and were feeding entirely on 

 the worms. The number in each stomach, determined by actual count, ranged 

 from seventy to a hundred and one, and it was usually nearly a hundred. These 

 tiiirty birds were therefore eating the pests at the rate of at least three thousand 

 a day, or ninety thousand for the month during which the caterpillar is exposed 

 to their attacks. 



Another valuable species was the black-throated bunting (Spiza Americana). 

 This confined itself less strictly to the worms for food than the foregoing, but 

 was much more abundant and Avas nesting in the orchard. Eleven birds were 

 examined, and eight of them were found to have eaten canker worms, which 

 made about half the total food of the whole number. Besides the above, the 

 indigo bird ate them in the ratio of seventy-eight percent; the chickadee, 

 seventy-five per cent: the black-billed cuckoo, seventy-five ; the summer warbler 

 and the rose breasted grosbeak, each sixty-six ; the bluebird, sixty ; the king- 

 bird, forty-three; the robin, forty; the warbling vireo, thirty-five; the red- 

 headed woodpecker, thirty-two ; and the brown thrush, twenty-three per cent. 



Of the species which were not found eating the worms at all, none but the 

 catbird and the wood pewee were represented by more than a single specimen, 

 so that it is very probable that more species would have been proved to be destruc- 

 tive to the caterpillars if a greater number had been shot. 



The benefits due to the thrush family and the bluebird were materially 

 diminished by their attack on the predacious beetles, which made about sixteen 

 per cent of their food ; and these beetles, as I found by examining the contents 

 of the alimentary canals of several representatives of eight species taken in the 

 orchard, were making about one-sixth of their food from the worms. 



A comparison of the food ratios of the birds shot in this orchard with those 

 of other birds of the same species, taken in the same month (May), in a 

 miscellaneous variety of situations, showed that the birds in the orchard were 

 eating caterpillars much more freely than was their ordinary habit. For 

 example, caterpillars were found to make but thirteen per cent of tlie ordinary 

 food of certain of tlie thrushes, while they made forty per cent of the food of 

 the same species in the orchard. 



The ordinary May food of the bluebird contained but twelve per cent of 

 caterpillars, while the single one shot in the orchard had taken sixty per cent 

 of its food from them. These insects are usually eaten in May by the black- 

 throated bunting in the ratio of about twenty per cent, while they made 

 seventy per cent of the food of those shot among the canker worms. 



This is evidence that, however well-marked the distinctive preferences of the 

 various species may be, they are not inflexible, but yield to the temptation of 

 an unusual and easily-obtainable supply of some one kind of food. It is 

 evidently to this fact that the usefulness of birds is due in checking any 

 uprising of insects beyond the ordinary limits of the species. 



