PRELIMINARY REPORT ON THE FOOD OF WOODPECKERS. 



By F. E. L. Bbal, Assistant Ornithologist. 



GENERAL EBMAKKS. 



With the possible exception of the crow, no birds are subject to more 

 adverse criticism than woodpeckers. Usually no attempt is made to 

 discriminate between the numerous species, and little account is taken 

 of the good they do in destroying injurious insects. The name ' Sap- 

 sucker ' has been applied to two or three of the smaller kinds, in the 

 belief that they subsist to a great extent upon the juices of trees, 

 obtained from the small holes they make in the bark. There can be 

 little doubt that one species, the Yellow-bellied Woodpecker [Spliyra- 

 picus varius), does live to a considerable extent upon this sap. Obser- 

 vation does not show that other species have the same habit, but it is 

 a difficult point to decide by dissection, as fluid contents disappear 

 quickly from the stomach. 



Many observers have testified to the good work these birds do in 

 destroying insects, while others have spoken of harm done to fruit or 

 grain. Both are correct within certain limits. 



Field observation on the food habits of birds is attended with so 

 many difficulties as to render it a very unreliable source from which to 

 draw general conclusions. The most conscientious and careful person 

 is often deceived, not only as to the quantity of a particular kind of 

 food eaten by a bird, but as to the fact that it is eaten at all. The 

 further difficulty of keeping a number of birds, or even a single one, 

 under constant observation makes an estimate of relative proportions 

 of different kinds of food impossible. When much mischief is done 

 the fact is apparent, but there is no way to find out how much good is 

 done during the same time. For these reasons it often happens that 

 reports on food habits, based on observations of wild birds, not only 

 conflict with each other but also disagree with the results obtained 

 from stomach examinations. This last method must be taken as the 

 court of final appeal, and it is evident that a collection of stomachs 

 covering every month in the year, and as nearly as may be all points 



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