BUTEO SWAINSONI, SWAINSOn's BTJZZAED. 359 



hoppers. They procure gophers, mice, and other small quadrupeds, both 

 by waiting patiently at the mouth of the holes, ready to claw out the 

 unlucky animals the moment they show their noses, and by sailing low 

 over the ground to pick up such as they maj' find away from home. 

 But I question whether, after all, insects do not furnish their principal 

 subsisfence. Those that I shot after midsummer all had their craws 

 stuffed with grasshoppers. These insects, which appear sometimes in 

 almost inconceivable numbers, seem to be the natural source of supply 

 for a variety of animals. Wolves, foxes, badgers, and even rodents, 

 like gophers, supposed vegetarians, come down to them. Sand-hill 

 Cranes stalk over the plains to spear them by thousands. Wild fowl 

 waddle out of the reedy pools to scoop them up. We may kill scores 

 of Sharp-tailed Grouse, in September, to find in every one of them a 

 mass of grasshoppers, only leavened with a few grubs, beetles, leaves, 

 berries, and succulent tops of plants. It is amusing to see a Hawk 

 catching grasshoppers, skipping about in an awkward way, and looking 

 as if he were rather ashamed of being seen in such a performance. 

 Food being abundant and easily procured, the birds become extremely 

 fat early in the autumn, and lazy withal. Unaccustomed to the pres- 

 ence of man in these regions, they may be approached with little difB^- 

 culty as they perch on the trees ; and they often fly unwillingly within 

 short range. When brought down winged, they show no lack of spirit, 

 and must be prudently dealt with, as their talons are very effective weap- 

 ons of defense. 



Changes of plumage -with age affect more particularly the under parts, the hack, 

 wings, aud tail being more nearly alilie at all times. 



Yonng-of-ilie-year (both sexes). Entire npper parts dark brown, everywhere varied 

 with tawny edgings of the individual feathers. The younger the bird, the more marked 

 is the variegation ; it corresponds in tints closely with the color of the under parts, 

 being palest in very young examples. Under parts, including lining of wings, nearly 

 unilorm fawn-color (pale, dull yellowish-brown), thickly and sharply marked with 

 blackish-brown. These large dark spots, for the most part circular or guttiform, crowd 

 across the forebreast, scatter on the middle belly, enlarge to cross-bars on the flanks, 

 become broad arrow-heads on the lower belly and tibiae, aud are wanting on the throat, 

 which is only marked with a sharp, narrow, blackish penciling along the median line. 

 Quills brownish-black, the outer webs with an ashy shade, the inner webs toward the 

 base grayish, paler, and marbled with white, and also showing obscure dark cross- 

 bars ; their shafts black on top, nearly white underneath. Tail-feathers like the quills, 

 but more decidedly shaded with ashy or slate-gray, and tipped with whitish ; their 

 numerous dark cross-bars show more plainly than those of the quills, but are not so 

 evident as they are in the old birds. 



Adults (either sex). Upper parts dark brown, very variable in shade according to 

 season or wear of the feathers, varied, with paler brown, or even reddish-brown edit- 

 ings of the feathers, but without the clear fawn-color of the young; the feathers of 

 the crown showing whitish when disturbed, and usually sharp, dark shaft-lines ; the 

 upper tail-coverts chestnut and white, with blackish bars. Quills and tail-feathers as 

 before, but the inner webs of the former showing more decided dark cross-bars upon a 

 lighter marbled-whitish ground, and the latter having broader and sharper, dark wavy 

 bars. These large quills, and particularly those of the tail, vary much in shade ac- 

 cording to wear, the new feathers being strongly slate-colored, the old ones plain dark 

 brown. The tail, however, never shows any trace of the rich chestnut that obtains in 

 the adnlt JB.borealis. Male: Under parts showing a broad pectoral area of bright 

 chestnut, usually with a glaucous cast, and displaying sharp, black shaft-lines ; this 

 area contrasting sharply with the pure white throat. Other under parts white, more 

 or less tinged and varied, in ditferent specimens, with light chestnut. In some fuales, 

 this chestnut is diminished to traces, chiefly in flank-bars and arrow-heads, and the 

 white throat is immaculate ; in others, the throat shows blackish penciling, and the 

 rest of the under parts are so much marked with chestnut, chiefly in cross-bars, that 

 this color predominates over the white, and appears in direct continuation of the pec- 

 toral area itself. Some feathers of this area are commonly dark brown. Female : Much 

 darker underneath than the male ; throat pure white, but other under parts probably 

 never whitening decidedly. Pectoral area from rich, dark chestnut or maliO;j:auy-color, 

 mixed with stUl darker feathers, to brownish-black ; aild other under parts heavily 



