422 Roosevelt Wild Life Bulletin 



them, spending much time in clinging to the trunk and alternately 

 drinking the accumulating sap and enlarging the wells. A large 

 tree thus affected will be frequented by several Sapsuckers very 

 regularly in midsummer, and one or more juveniles may spend 

 most of the day in such a tree. A family of Sapsuckers has several 

 tapped trees within a convenient radius, and after the young are 

 out of the nest their days are spent chiefly in loitering at one or 

 another of them. 



In estimating the apparently destructive effect of this habit of the 

 Yellow-bellied Sapsucker we must consider the influence of the 

 birches in the forest association, remembering that an undue pro- 

 portion of any single element is likely to be as detrimental to the 

 forest as is the lack of a certain species. As nearly as I could ascer- 

 tain, at least six families of this woodpecker dwelt in the Barber 

 Point neighborhood. No birch tree at the Camp had been materially 

 injured. In the Partial Clearing four mature birches were regularly 

 visited by Sapsuckers, and all showed old perforations, eight to 

 fifteen feet above the ground, or higher. None of the four grew to 

 full height, and none appeared to be bearing seed. The Sapsuckers 

 were not making new holes in these trees, but were occasionally 

 enlarging old perforations by chiseling into them and smoothing their 

 edges. The one most persistently worked on was a tall, half -broken 

 snag, with only a tuft of branches at its top, and this crippled 

 remnant was the chief food resource for its Sapsucker family. I 

 sought diligently for evidence of Sapsucker attacks on younger 

 branches, but was unable to find any ; and my conclusion is that these 

 birds perfer to open old perforations rather than to make new ones. 

 Most birches do not suffer seriously, and only a relatively small 

 number of mature trees in a habitat are tapped at all. Frequently 

 a Sapsucker will work industriously on the trunk of a mature birch 

 for many minutes, seeking to extract a morsel of insect from its 

 burrow, without any apparent intent of making perforations for 

 sap. If even a small percentage of the attacked birches die, how- 

 ever, the Sapsucker thereby becomes an agency for the restriction 

 of the species. It is certainly the cause of considerable local injury, 

 but as the birch is a fairly constant constituent of the Adirondack 

 mixed forest, and as the Sapsuckers' interrelations with it have long 

 existed, there probably has come about a fair adjustment between the 

 two. It is to be noted that the Yellow-bellied Sapsucker is not an 

 inhabitant of dense woods, but rather of the forest margin, burns 

 and open areas. 



We are indebted to E. H. Forbush ('13, p. 122) for an account 

 of the relation between the birds and the plant lice that infest the 

 birch. " It is a widely known fact in Massachusetts," he records, 

 " that practically all of the resident and migrant warblers eat the birch 

 plant louse. It is only necessary for one to find a locality where 

 these insects are numerous if he wishes to make sure of finding in 

 their seasons about all the warblers that breed in that region or 

 migrate through it, and also many other birds not ordinarily found 



