INSECT FOOD. 33 



conspicuous of all forms of insect life. Of the 645 native birds collected, 

 147 had fed on them. Woodpeckers, ^catchers, night-hawks, swal- 

 lows, catbirds, and white-throated sparrows seemed to have the most 

 liking for them. 



A large ant very frequently eaten is a black species, Camponotus 

 pennsylvanicus. which during the warmer half of the year is very 

 abundant on tree trunks. Its habits expose it to attack by several 

 kinds of birds. The down v woodpecker was constant^ making spiralis 

 around the trunks of trees at Marshall Hall in vigilant search for these 

 insects. The catbird was seen feeding on them as the}' journeyed on 

 the ground from tree to tree. These two birds probably destroy 

 more than an}' other species, though the sapsucker also appears to 

 relish them. The small species of ants are eaten much oftener than 

 the larger ones, especially at their swarming time. For several days 

 during the middle of April. 1899. great swarms of corn-louse ants 

 (Zasius) were taking their marriage flight, and of the 55 birds collected 

 then, mostly native sparrows, 23 had joined in the work of destroying 

 them. This was a valuable service, for destruction of the corn-louse 

 ant is the only effective means of combating the corn louse, which 

 this ant protects and disseminates. Swallows, also, often attack the 

 corn -louse ant. On July S. 1S9S. six out of seven rough- winged 

 swallows collected on the farm had fed on it and on little else, one bird 

 containing -10 ants and another 50. ^At the same time kingbirds, house 

 wrens, marsh wrens, yellow warblers, song sparrows, and chipping 

 sparrows were making inroads on it, though it was much less numer- 

 ous than during April, 1899. In the late afternoon of Julv 18. 1898, 

 flying ants of the species 2fyrmica scahrinodes^ which, as Prof. S. A. 

 Forbes has shown, injure corn both when it is sprouting and when it 

 is in milk and also foster the corn louse, were so abundant over lots 

 1 and 2 that their gauzy wings in the level sun rays tilled the air with 

 shimmering rainbow colors. Bank swallows were circling among 

 them, close to the ground, making a hearty supper. By crouching 

 low one could see them catch the insects, sometimes within a few feet 

 of one's head. AYhile the flock were feeding, four birds were collected. 

 They had consumed practically nothing but ants and contained, all 

 together, just 20(>. At this rate. 250 swallows — a fair estimate of the 

 number present — would consume in a single afternoon 12,500 ants. 

 Many other birds were feeding on them, including night-hawks, a 

 single one of Avhich has been known to eat 1.000 at a meal. A house 

 wren, a yellow warbler, a chipping sparrow, and a phoebe. which were 

 collected earlier, had all taken them, but three swifts collected after 

 sunset had not. 



On August 5, 1898, SoJenojysis molesta, an ant injurious to corn and 

 also a household pest, was swarming, and a number of birds were prey- 

 ing on it. In a newly mown timothy field near the cow barn a dozen 

 7222— No. 17—02 3 



