SWAINSON'S HAWK 229 



the day in the poplar trees along the river bottom. Here I found the trees 

 literally full of hawks, and counted as many as thirteen in one tree. Two 

 of the three whose stomachs were examined contained grasshoppers and no 

 other food. The third contained, in addition to grasshoppers, the head of a 

 meadow mouse of the genus Arvicola (subgenus ChUotus). One contained 

 88 grasshoppers, another 96, and the third 106. * * * 



Assuming that each hawk captured 200 grasshoppers a day and that there 

 were 200 hawks, the daily catch would be 40,000 grasshoppers. At this rate 

 these hawks would destroy 280,000 grasshoppers in a week and 1,200,000 in a 

 month. * * * When in southern California about a month later I was 

 told by Mr. Edwai'd Merriam that on three occa.sions he had noticed similar 

 gatherings of hawks in San Diego County, Once he saw a flock of several 

 hundred large hawks catching crickets in cracked adobe soil in the San Mar- 

 cos Valley. At night the hawks came into the live oaks at the head of the 

 valley to rest. He shot one and found its stomach packed full of large black 

 crickets. 



He also quotes H. W. Henshaw on another useful habit as follows : 

 "Camping here [San Fernando Valley, Calif.] one evening our atten- 

 tion was directed to the great number of gophers {Spei^mophilus 

 heecheyi) which in large colonies inhabited some barren hills near the 

 station. Toward dusk the place was visited by at least a dozen of 

 these birds, which took up their positions on the hillocks thrown up 

 by the animals in front of their burrows, and awaited with patience 

 the moment when a favorable opportunity should occur to snatch a 

 supper. Elsewhere I have frequently seen them thus employed, and 

 their persistence in destroying these pests should entitle them to due 

 consideration at the hands of the farmer." 



John V. Crone observed a large number of Swainson's hawks 

 moving about in the air and has sent me the following interesting 

 note: "Soon someone observed that one and then that others were 

 constantly extending their feet forward and apparently picking at 

 them with their beaks. This seemed a curious habit so we watched 

 closely, when the interesting and significant fact became apparent 

 that these splendid birds were busily engaged in catching and eating 

 insects while flying through the air. Wlien we discovered this wei 

 spent more time in finding out how it was done. The insects were 

 seized by the bird's feet. Nearly all the volplaning, somersaulting, 

 circling, and other gyrations of the hawk ended with a quick thrust 

 of the foot, which seemed rarely to miss the prey." 



I can find no evidence that this hawk ever attacks poultry or game 

 birds, and most observers agree that it seldom, if ever, kills birds of 

 any land. Coues (1874) says: "I scarcely think they are smart 

 enough to catch birds very often. I saw one make the attempt on 

 a Lark Bunting. The Hawk poised in the air, at a height of about 

 twenty yards, for fully a minute, fell heavily, with an awkward 

 thrust of the talons — and missed. The little bird slipped off, badly 

 scared no doubt, but unhurt, while the enemy flapped away sulkily, 



