National Geographic : 1913 Jun
Photo by Mrs. F. W. Roe BLUE JAYS (SEE PAGE 687) The blue jay, I fear, is a reprobate; but, notwithstanding his fondness for eggs and nestlings, and his evident joy in worrying other birds, there is a dashing, reckless air about him which makes us pardon his faults and like him in spite of ourselves. Like many men, he needs the inspiration of congenial company to bring out the social side of his disposition. When at home he is very different from the noisy fellow who, with equally noisy comrades, roams the woods in the fall. coursing rapidly to and fro, ever in pur suit of the insects, which constitute their sole food. When they retire, the night hawks and whippoorwills will take up the chase, catching moths and other noc turnal insects which would escape day flying birds. The flycatchers lie in wait, darting from ambush at passing prey, and with a suggestive click of the bill returning to their post. The warblers-light, active creatures flutter about the terminal foliage, and, with almost the skill of a humming-bird, pick insects from leaf or blossom. The vireos patiently explore the under sides of leaves and odd nooks and corners to see that no skulker escapes. The wood peckers, nuthatches, and creepers attend to the tree trunks and limbs, examining carefully each inch of bark for insects' eggs and larve, or excavating for the ants and borers they hear at work within. On the ground the hunt is continued by the thrushes, sparrows, and other birds, who feed upon the innumerable forms of terrestrial insects. Few places in which insects exist are neglected; even some species which pass their earlier stages or entire lives in the water are preyed upon by aquatic birds. A CONSTANT WARFARE AGAINST INSECTS Birds digest their food so rapidly that it is difficult to estimate from the con tents of a bird's stomach at a given time how much it eats during the day. The stomach of a yellow-billed cuckoo shot at 6 o'clock in the morning contained the partially digested remains of 43 tent cat erpillars, but how many it would have eaten before night no one can say. Mr. E. H. Forbush, ornithologist of the Board of Agriculture of Massachu setts, states that the stomachs of four chickadees contained 1,o28 eggs of the cankerworm. The stomachs of four other birds of the same species contained about 6oo eggs and 105 female moths of the cankerworm. The average number of eggs found in 20 of these moths was 185, and, as it is estimated that a chickadee may eat 30 female cankerworm moths per day during the 25 days which these moths crawl up trees, it follows that in this period each chickadee would destroy 138,750 eggs of this noxious insect.