SWAINSON'S HAWK. 237 



home immediately under the nest of these Hawks or in the sides of it. Two 

 such instances came under my personal observation. 



The food of Swainson's Hawk consists almost entirely of the smaller 

 rodents, principally striped gophers and mice, as well as grasshoppers and the 

 large black cricket, which is very common as well as destructive in certain sea- 

 sons, and the bane of the farmers in eastern Oregon, Washington, Idaho, 

 Nevada, and other localities in the Great Basin, destroying and eating up every 

 green thing as they move along. Even the bitter leaves of the sage bush, 

 Artemisia, are not despised by these pests, and while these last they constitute 

 their principal food. From almost daily opportunities enjoyed by me for 

 years of observing this bird, I do not hesitate to say that aside from an 

 occasional half-grown hare or rabbit, which from their abundance in some 

 of the regions referred to are themselves considered as quite a nuisance, its 

 daily fare consists almost exclusively of such food as I have mentioned. 



I cannot recall a single instance where one of these birds visited a poultry 

 yard; and if other food is procurable it will seldom molest a bird of any kind. 

 From an economic point of view I consider it by far the most useful and 

 beneficial of all our Hawks. It is found in a great variety of plumages and in 

 some stages it is an exceedingly handsome bird. 



In the more northern portions of its range it is only a summer resident, 

 migrating regularly in large straggling flocks. In the fall of 1881, while 

 encamped near the Umatilla Indian Agency, in Oregon, I noticed numbers 

 of these birds passing; I should think that not less than two thousand of them 

 flew by in straggling bands and settled down on the foothills a few miles south 

 of the agency. They were evidently returning from their breeding grounds in 

 the North, and as they flew rather low could be readily identified, although 

 they varied greatly in plumage. As near as I could tell this body of Hawks 

 seemed to be almost exclusively composed of this species. . 



On the eastern slopes of the Rocky Mountains it winters from about lati- 

 tude 39° southward, a few remaining in favorable localities still farther north. 

 On the Pacific coast I have observed a few wintering in southeastern Oregon in 

 ' about latitude 42°, the majority passing southward, and the birds remaining are 

 probably such as breed much farther north, replacing the regular summer resi- 

 dents, which in turn move south on the approach of cold weather. 



Swainson's Hawk, as a rule, nests late in the season, even in some of the 

 southern portions of its range. This, however, does not seem to hold good 

 everywhere, as Mr. William Lloyd informs me that on the prairies west of 

 Chihuahua, Mexico, he took eggs of this species on March 6; Mr. William 

 Cobb took some in central New Mexico, March 20, and Mr. F. Stephens in 

 southern California on April 16. 



In the large series of eggs of this species in the U. S. National Museum 

 collection, consisting of one hundred and sixty-six specimens, which represent 

 nearly every State and Territory west of the Mississippi River, from Arizona 

 to Alaska and the Arctic regions, there is but a single set taken as early as 



