92 



WOODPECKERS IN RELATION TO TREES. 



Joseph Grinnell records the following observation upon the same 

 species of woodpecker : 



At Seven Oaks, June 24, 1906, we had been watching a Sierra sapsucker (Sphyrapicus 

 v. daggetti) industriously running a line of bark pits around the branch of an alder, 

 when a California woodpecker . . . flew down and drove off the sapsucker . . . then 

 went the rounds of the borings himself, "dipping" from each. 1 



This observation suggests that the other records of species of wood- 

 peckers besides sapsuckers tapping trees should refer only to their 

 purloining sap from punctures made by the latter. Be that as it 

 may, the assertion has frequently been made that some of our wood- 

 peckers, notably the downy and the hairy, mark trees in a fashion 

 almost indistinguishable from that of the sapsucker. Some of the 



European woodpeck- 

 ( . ers very closely re- 



, ... ( ^:v lated to our species of 



the genus Dryobates 

 do a great deal of 

 similar work, even 

 producing large swol- 

 len girdles on trees, 2 

 and it would be sur- 

 prising if our species 

 were found to be en- 

 tirely innocent of 

 such practices. Mr. 

 Henry Bryant, of 

 Boston, published 

 the following testi- 

 mony in 1866: 



It lias long been known 

 that si line of our smaller 

 woodpeckers pick out por- 

 tions of the sound bark of 

 trees, particularly of apple 

 trees, where there are no 

 larva- and apparently no inducement for them to do so. . . . They [the pecks] are 

 generally seen in circles round the limbs or trunks of small irregularly rounded holes, 

 and in this vicinity are made almost exclusively by the downy woodpecker, 

 I', pubescens, aided occasionally by the hairy woodpecker, P. villosus. 3 

 Dr. J. A. Allen corroborates these statements as follows: 

 The perforations made in the bark of trees by woodpeckers, forming transverse rings, 

 and sometimes so numerous as to do serious injury to the trees, have of late been very 

 commonly attributed almost solely to this species [yellow-bellied woodpecker], 

 especially at the West, where it is so numerous. That it is. from this habit, often 

 greatly injurious to fruit trees is not to be denied : but that this species — now commonly 

 styled the "true sapsucker," to whose depredations it is said should be assigned the 



' t'niv. Calif. Pub. Zool., V, 65 66, 1908. 



4 See Fuchs, Gilbert, tiber das Ringeln der Spechte undihrVerhaltengegen diekleineren ForstschM* 

 linge. Naturwiss. Zeitschr. f. Land a. Forstwirtscnaft, III. 317-341, 1905. 

 3 Proa Bost. Boa Nat lli-t.. x. 91 -2, 1866. 



Fig. 38»— Yellow-bellied sapsucker. Note the black spot on breast. 



