32 



NEW YORK STATE MUSEUM 



XROGLODYXIDAB 



The house wren is the only species that has been seen by our observers 

 to eat hairy caterpillars. It can hardly be called a common bird, and it has 

 only occasionally been seen to eat these caterpillars. 



F»A.RIDAE 



Nitt hatches and titmice 



The chickadee, the common representative of the titmouse family, and 

 one of the most useful of all birds, is a great destroyer of hairy caterpillars. 

 Not only does it eat caterpillars of all sizes, feeding them to its young, but 

 it destroys all forms of these insects, except, perhaps, the eggs of some 

 species. Too much can not be said in favor of this most useful and harmless 

 bird. Both species of nuthatch take these larvae only as they come in their 

 way on the trunks of trees, and not always even then. 



XUROID AE 



Tliriishes 



While the thrushes eat hairy caterpillars when they come in their way, 

 they do not, with the exception of the robin, appear to search them out. 

 The robin seems to be in this way the most useful of all thrushes. The 

 wood thrush and Wilson's thrush occasionally visit localities infested by the 

 caterpillars and eat a few, but the robin visits them frequently and eats 

 many. The thrushes eat mainly the larger caterpillars. 



The bluebird is useful in destroying most forms of these insects, but as 

 bluebirds are not plentiful in the infested region the opportunity for obser- 

 vation has not been so good as in the case of some other species. 



Prof. S. A. Forbes, state entomologist of Illinois, has made an extended 

 study of the food habits of different birds and he estimates that there are 

 about 10,000 ypsects per acre over the entire state, and on this basis con- 

 cludes that if the operations of birds were suspended entirely for a period 

 of seven years, the entire state would be carpeted with insects, one to the 

 square inch. Professor Forbes gives this as an illustration, by no means as 

 a prediction, and it certainly is a graphic way of stating the high value he 

 places on bird life as a means of checking the depredations of insect pests. 

 Professor Forbes has estimated that should the people of the state apply 

 appropriate measures to increase the efficiency of bird life in destroying 

 insects, even if it was no more than \'',r, the agriculturists of that state would 

 be saved $76,000 a year at the lowest, and probably five. times that amount. 



