No. 4.] BIRDS AND WOODLANDS. 319 



Injury done by Birds to Woodlands. 

 There can be no doubt that some slight injury may be done 

 to the trees by birds. The grosbeaks and the purple iiuchcs 

 eat buds and blossoms, grouse feed largely on young buds, 

 crows and jays eat nuts, crossbills take the seed and buds 

 from coniferous trees, and woodpeckers sometimes bore into 

 sound trees ; but the injury done is so slight, compared with 

 the benefits conferred by birds in })rotecting trees from their 

 enemies and in distributing and })lanting seeds, that it need 

 hardly be considered in making up the account. It is now 

 said in favor of the much-abused sapsucker, that it is the 

 perforations made by its beak which produce much of the 

 appearance called "birdseye" in the maple. This greatly 

 incieases the vahie of this tree for timber use. Forest birds 

 appear to have been especially designed to maintain that 

 balance of forces in the forest which is essential to its preser- 

 vation, and we may well fear that without their assistance 

 profitable forestry would be impossible. In this matter there 

 is no higher authority than the distinguished entomologist, 

 Prof. S. A. Forl)es of Illinois, who says that estimates of the 

 average number of insects per square yard in that State give 

 ten thousand per acre for the entire area, and that if on this 

 basis the operations of birds were to be suspended entirely, 

 the entire State in seven years would be carpeted with insects 

 one to the square inch. This would certainly happen unless 

 the insects w^ere checked by some providential means. Pro- 

 fessor Forbes says that this is intended only as an illustration, 

 and not as a prediction of the consequences of the total 

 destruction of birds, which he says would not be so simple, 

 but apparently fully as grave. He also estimates that, should 

 the people of the State succeed in taking measures which 

 would increase by so much as one per cent the efficiency of 

 the birds of the State as insect police, the eftcct would be to 

 save to the agriculturists of the State $7G,000 per year; but 

 he regards five times this amount as a very modest estimate, 

 for he says the figures on which his estimates are made, " will 

 be regarded by most naturalists as absurdly low."* 



* Bulletin No. 3, Illinois State Laboratory Natural Historj', November, 1880, p. 81. 



