HABITS OF SAPSUCKERS. 
17 
Fig. 3. 
>piny tongue of downy woodpecker (Dryobatcs pubcsctns). 
Lucas, Rept. U. S. Nat. Mus., 1895.) 
(From 
In keeping with their peculiarities of structure, these brush- 
tongued woodpeckers have peculiar food habits. They are the true 
sapsucking and cambium-eating species. They girdle and kill many 
trees, either by destroying extensive areas of the cambium or more 
commonly by removing many small pieces in such a way as to sever 
most if not all the channels carrying the elaborated sap from which 
both wood and bark are formed. 
The three species are probably equally to blame. While it has 
been asserted that the red-breasted and Williamson sapsuckers harm 
trees less than the yellow-bellied, these statements are probably 
founded on in- 
sufficient infor- 
mation. There 
is a dearth of 
data respecting 
the habits of 
these two woodpeckers, but similarity of structure and the evidence 
of stomach examinations indicate that the three species of sapsuckers 
are much alike in their cambium-eating habits and hence all three are 
injurious to trees. The Williamson sapsucker, however, is strictly an 
inhabitant of pine forests and aspen groves at considerable elevations, 
and therefore under present conditions is not likely to injure trees of 
great value to man. 
Stomach examinations show that the red-breasted sapsucker con- 
sumes enough cambium and bast to average 12.16 per cent of its 
food. The same food constitutes 12.55 per cent of the stomach con- 
tents of the Williamson sap- 
suckers examined and 16.71 
per cent of the yellow-bellied 
woodpecker's diet, an aver- 
age amount for the three of 
13.8 per cent. It must be 
Fig. 4.— Brushy tongue of sapsucker (Sphyrapicus variUs). 
(From Lucas, Rept. U. S. Nat. Mus., 1895. 
noted also that cambium is a very delicate, perishable material, at 
certain times no more than a jelly, and thus never receives a percent- 
age valuation in examinations of long-preserved stomachs correspond- 
ing to its bulk when first swallowed. Neither do we get any record 
of the sap consumed by these birds, and they are inordinate tipplers. 1 
Hence the value of the percentages cited lies not so much in their 
accuracy as to the quantity of cambium eaten as in the fact that they 
indicate a steady consumption of this important substance. There 
1 A yellow-bellied sapsucker has been observed to remain within a yard of some of its holes in a maple 
tree, drinking the sap at frequent intervals, from 10 a. m. to 5 p. m. 
99068°— Bull. 39—11 2 
