SWAmSON'S HAWK. 237 



liome immediately under the nest of tliese 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, princij^ally 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 

 tlieir principal food. From almost daily oj)portunities 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, Avhich from their abundance in some 

 of tlie 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 procural)le it will seldom molest a bird of any kind. 

 From an economic point of view I consider it by tar tlie 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 thousaijd of them 

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

 of the agency. They were e\'idently returning from tlieir breeding grounds in 

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

 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 winterino- in southeastern Oreo-on in 

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

 probably such as breed much farther north, rei)lacing 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 tlie 

 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 fi; Mr. William 

 Cobb took some in central New Mexico, ]\Iarch 20, and Jlr. F. Stephens in 

 southern California on April 16. 



In the large series of eggs of this sjiecies 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 Ai'ctic regions, there is but a single set taken as early as 



