108 BIRDS IN THEIR RELATIONS TO MAN. 



the actual average, could we determine it precisely. Insects 1 

 eggs of many other kinds were found in the food of the chick- 

 adee ; many of these it was impossible to recognize, but there 

 was no difficulty in identifying the eggs of the common Ameri- 

 can tent caterpillar and of the fall canker-worm, the eggs 

 of which remain upon the trees through the winter. There 

 were also present the eggs and egg-sacs of many spiders of 

 kinds commonly occurring under loose bark. While spiders 

 as a class are doubtless beneficial creatures, the destruction 

 of some of them is not in our opinion seriously detrimental to 

 the usefulness of the chickadee. The larvae of several differ- 

 ent kinds of moths were also found. One of the most abun- 

 dant species was believed to be the common apple-worm, the 

 larvae of the codling moth. The bark-beetles of the family 

 Scolytidae, which are destructive to forests all over our coun- 

 try, were also freely eaten by the chickadees. The hairy 

 skins of the fruits of the common wild sumachs were among 

 the most abundant elements of the vegetable food present. 

 The edible portion of these fruits is evidently eaten to a con- 

 siderable extent throughout the winter and early spring. An- 

 other common element of the food appears to consist of the 

 curious little fruits of the bayberry or waxberry myrtle an 

 abundant shrub along the sea-coast. In winter chickadees 

 have been observed to hide away surplus food, to eat at a 

 later time. 



A careful study of the food of the chickadee in Michigan 

 has also been made by Professor E. D. Sanderson, with re- 

 sults very similar to those recorded above. As an indication 

 of the usefulness of these birds, he writes : "If fifty-five in- 

 sects were consumed per day by each bird, as will be shown 

 to be the case, three hundred and eighty-five would be con- 

 sumed per day by a flock of seven, which is believed to be a 

 fair average for each square mile : this would be about one 

 hundred and thirty-seven thousand five hundred per year in 

 each square mile. Thus upon the land surface of Michigan 



