8 The Regulative Action of Birds upon Insect Oscillations. 



SAXICOLIDyE. Bluebirds. 

 SiALiA siALis, L. Bluebird. 



This species was not at all abundant in the orchard in either 

 year. Only one was taken in 1881, and four in 1882. All but 

 two per cent, of the food of these five specimens consisted of 

 insects, spiders making the remainder. Canker-worms were 

 twelve per cent, of the food, and other Lepidoptera five per cent, 

 additional. Two-thirds of the food consisted of Coleoptera. 

 Carabidffi made more than one-third (twenty-three per cent.), 

 belonging chiefly to a species [Anisodactylus baltimorensis) 

 which depends largely upon vegetable food. Four of the 

 birds had eaten Anomala binotata, which made thirty-six per 

 cent, of the food of the whole. Five per cent, was Chrysomelidae, 

 and fifteen per cent. Hemiptera, all belonging to the family 

 Cydnidai. 



PARID^. Chickadees. 



PaRUS ATRICAPILLUS, L. BlACK-CAPPED ChICKADEE. 



This little bird, unfortunately, was not at all common in the 

 orchard; and only two specimens were taken, one in each year. 

 Sixty-one per cent, of their food consisted of canker-worms, eaten 

 by both the birds, and Coleoptera made the entire remainder. 

 These were nearly all Cerambycidas {Fsenocerus sicjyernotatus) 

 and Rhynchophora of undetermined species, twenty-five per cent, 

 of the former, and ten of the latter. 



TROGLODYTID^. Wrens. 

 Troglodytes domesticus, Bartr. House Wren. 



Several specimens of this little species were observed, some of 

 them evidently nesting. The food was chiefly insects, — all, in 

 fact, but six per cent, of spiders and one of thousand-legs. 

 Nearly half the food of these birds consisted of canker-worms, 

 and other Lepidoptera and their larvae brought the average of the 

 order up to fifty-nine per cent. A few gnats and other Diptera 

 (four per cent.) and five per cent, of ants were also noted. Cole- 

 optera and Hemiptera were taken in nearly equal quantities, thir- 

 teen per cent, of the former and ten of the latter. Two of the 



