--In February of 1939, at rny horne in
Berkeley, California, I noticed that the California Purple Finches (Carpodacus purpureus californicus)
were singing every morning in a plum tree which was in full bloom. On closer observation the birds
were seen to be plucking blossoms. Each bird worked systematically, and in one movement picked
a blossom and snipped open the base ;- it then removed the nectar while holding the blossom in the
bill, following which it dropped the blossom to the ground. Upon examination the dropped blossoms
were found to be undarnaged except for rernoval of the nectar. The birds' unhurried swiftness was
interrupted only when they paused to sing. In March the purple finches transferred their attentions
to the apricot trees and continued the same procedure. Four of the eigbt trees which were under
observation were worked consistently, while the other four trees were not. Of the four trees that were
not worked one had been pruned.
In July and August when the fruit ripened, the four apricot trees whose blossoms had been thinned
by the purple finches had fewer, but larger, fruits. Of the four apricot trees which had not been
visited by the purple finches the three unpruned trees were loaded with small fruit. In this instance
the purple finches presumably had been beneficial rather than harmful. The tree which was young
and had been pruned bore fruit comparable in size and quantity to the four trees visited by the purple
finches. Because observations were made for only one season, it is not possible to determine whether
these results were actually brought about by the purple finches or merely coincidental to other factors
such as soil fertility, moisture, insects, and the general health of the trees.
Was the nectar eating habit of the California Purple Finch formerly beneficial and is it now
harmful because of the introduction of man made factors? Is this habit harmful when practiced in
pruned orchards or is it of further benefit? Has this nectar eating habit always or ever been harmful,
or has it had any noticeable effect? These questions should be answered at least in part by further
observations. Different findings may be expected where different kinds of trees and different ecological
conditions are involved.--ND W. Srom, Berkeley, Cali]ornia, September 28, 1939.