302 



Bird- Lore 



«'« 



approached. Just as soon as I retreated, they immediately took up their posi- 

 tion on the tree again. They were as persistent in their nursing as a Htter 



of young pigs. 



As the young birds grew larger and stronger, 

 the adults made pits for them on trees whose 

 position was more nearly erect. By much urging 

 and the use of some force, the young birds were 

 js ;r^,— "a.uZ'^ '■■'^' induced to feed at the new pits and, as these 



'•C'^^^^-i^'.t-^j-'v.' were larger and more numerous than those on 



the horizontal tree, they remained in the new 

 position the greater part of the time. This per- 

 formance was repeated until the young birds 

 were able to take their sustenance from pits made 

 for them on vertical trees, as shown in Fig. i. I 

 do not assume from this that young Sapsuckers 

 cannot feed from a vertical position from the 

 iirst, for I have found many instances of these 

 rearing-places where the pits were placed on 

 vertical trees, as is shown in the case of Fig. 2. 

 It was apparent in the case of this particular 

 family of Sapsuckers that the young ones were 

 gradually taught to assume the vertical position. 

 The pits were arranged in groups eight to ten 

 feet from the ground. They were nearly square, 

 but with rounded corners (Fig. i), and were 

 from one-fourth to one inch in width and length. 

 The groups were easily seen from some little dis- 

 tance because of a kind of stain, similar to iron 

 rust in color, due to the exuding sap. A few pits 

 were made at first and, when these began to fail, 

 new ones were made above the old ones. This 

 was continued until a space of some three feet 

 was pretty well riddled, and the trunk com- 

 pletely girdled. The sap exuded from the upper 

 holes, coming down from above, and providing 

 the birds with the elaborated food material of 

 the tree. One might almost call it a predigested 

 food for the birds. The groups of birches gener- 

 ally selected for the purpose border a pond or 

 lake or brook. This probably assures a ready flow 

 of sap at all times. 



The young birds were persistent feeders, being 

 seen at the pits early in the morning, and at all 



->ST^ .-- 



GRAY BIRCH PITTED 

 SAPSUCKERS 



BY 



