378 BULLETIN 17 6, UNITED STATES NATIONAL MUSEUM 



foimd in the vicinity, but the Anna Hummingbirds seemed to find enough good 

 forage on the foliage of the golden oaks, about which they were seen almost 

 exclusively. The minute insects which live on the leaves of the golden oak 

 probably afforded sufficient forage of one sort, but the hummingbirds had another 

 source of food supply. 



It was noted that one or more Anna Hummingbirds were to be found regiv 

 larly nbout a certain golden oak, but the reason for their attraction to this 

 particular tree was not discerned for several days. Then, on December 11, one 

 of these birds was seen hovering before, and drinking from, some punctures 

 made by a Red-breasted Sapsucker in the bark of the oak tree. The hummer 

 visited puncture after puncture just as it would the individual blossoms in a 

 spike of flowers, and evidently partook of both the sap and the smaller of the 

 insects which had been attracted by the sap. 



It is rather contrary to the traditional conception of hummingbirds 

 that they should deliberately frequent the higher altitudes devoid of 

 flowers, but there are undoubtedly times, following especially severe 

 frosts, when members of this species in many parts of California 

 must be compelled to obtain their living in other than the usual way. 

 Mr. Dawson (1923) also mentions the use of sap: "Anna's Hummer 

 is fond of the sap of our common willows {Salix laevigata and S. 

 lasiolepis). It will also follow the Ked-breasted Sapsucker {Sphy- 

 rapicus ruber) into the orchards and glean eagerly from its deserted 

 borings. A catalogue of Anna's favorite flowers would be nearly 

 equivalent to a botany of southern California. But if one had to 

 choose the favorite it would probably be Ri2>es speciosum, our hand- 

 some red flowering gooseberry, for it is upon the abundance of this 

 flower that Anna relies for her early nesting." 



Naturalists in the eastern and northern parts of the countr\^ have 

 found that hummingbirds are more attracted to red flowers than to 

 those of any other color. The early-flowering gooseberry above men- 

 tioned and the paintbrush growing along a creek, which M. P. 

 Skinner, in his notes, tells of seeing an Anna's hummingbird visit 

 to the exclusion of other flowers, are both red ; but in all these cases 

 the flowers are probably seen against a green background, and since 

 red is the complementary color of green, the greater visibility of that 

 color may be more of a factor than any preference which the birds 

 might feel. At any rate, there seems to be no such favoritism in the 

 more arid parts of the Southwest, where the backgrounds are often 

 grayish or tawny. Bits of red and blue cloth seemed to attract equal 

 attention, though green was ignored. 



Like most young animals, immature hummingbirds are filled with 

 curiosity and are quick to investigate any brightly colored object; a 

 bunch of carrots will attract them as readily as a flower. Through 

 this process of trial they presently learn to discriminate among the 

 flowers and often to choose those of inconspicuous appearance over 

 the more brilliant kinds. As experience thus supplants curiosity, they 



