No. 128.] DIVISION OF ORNITHOLOGY. 71 



bark, and in some cases the edges even overhang. Thus the 

 hole is larger inside next the wood than outside, and gives 

 evidence that the Sapsucker sought the inner bark, for in every 

 case the perforations go down to the sapwood. 



With only two specimens of the work of these two species at 

 hand, and these varying considerably in the thickness of the 

 bark, no generahzations can be made, but the diflPerences be- 

 tween the two are evident to the naked eye and more so when 

 examined under a lens. However, the roughness shown on the 

 sides of the perforations made by the Downy may be due in 

 part to the greater age and more fibrous quality of the bark. 



If the Downy Woodpecker was taking cambium, it must 

 have secured very little in comparison with that taken by the 

 Sapsucker, which evidently ate or pecked out much more by 

 enlarging the perforations as they neared the wood. Most of 

 the holes made by the Downy either ended or tapered to a mere 

 point before the wood was reached. 



Dr. Joseph Grinnell of the University of California, Berkeley, 

 California, sends some manuscript describing his experience 

 with a pair of Willow Woodpeckers (Dryobates pubescens 

 turati). Dr. Grinnell and Mr. Tracy I. Storer watched a Willow 

 Woodpecker at work. They shot one bird, and found bits of 

 inner bark fibers adhering to the bristles about the bill, but 

 do not report that they have examined the contents of the 

 stomach. Their comparison of the work of the Willow Wood- 

 pecker and that of the Sapsucker follows: — 



A pair of Willow Woodpeckers proved to be regular tenants of Curry's 

 apple orchard on the floor of the Yosemite Valley. They or their ancestors 

 had evidently worked there for some years, with the result that most of 

 the 150 trees in the orchard showed marks of their attention, and many of 

 the trunks were fairly riddled with the somewhat Sapsucker-like drillings. 

 On November 8, 1915, two of us made a study of the site, with findings as 

 follows : — 



A measured area 6 inches (15 cm.) square, 4 feet (130 cm.) above ground 

 on a trunk 12 inches (32 cm.) in diameter contained 17 fresh pits and 30 

 old ones, of last year's digging or older. These pits were horizontally 

 elliptical, each about 2.5 by 4 mm. in surface extent, thus distinctly dif- 

 ferent in size and shape from true Sapsucker drillings. They were arranged 

 in irregular horizontal rows, with spaces of 6 to 14 mm. between individual 

 pits and 3 to 8 cm. between rows. On this particular trunk the pits 

 occurred over a vertical distance of 41 inches (105 cm.) so that there were 

 about 2,100 pits in all on this one tree. Limbs less than 4 inches (10 cm.) 



