306 BULLETIN 17 0, UNITED STATES NATIONAL MUSEUM 



buff" at the tips. Through this down the soft juvenal downy plumage 

 gradually comes in, and this is worn in slowly diminishing areas all 

 summer, or until it is replaced by the first winter plumage early in 

 fall. This is somewhat darker buff, especially on the breast, and is 

 barred with dusky, more heavily on the back and more faintly on the 

 breast; it is long and fluffy, especially on the thighs and rump; on 

 the head the down is short and soft, basally "cinnamon-buff", with 

 pale tips and barred with dusky; the ear tufts are only faintly indi- 

 cated, and there is much black or dark brown in the facial disks. 

 There is much individual variation in the colors of this plumage, fore- 

 casting the color phases of the adult; and the various races show their 

 racial characteristics to some extent at this age. In the meantime 

 the first winter plumage has been pushing out through this downy 

 plumage, first in the wings, then on the back, then in the tail, fol- 

 lowed by the rest of the body plumage, and finally on the head. The 

 primaries begin to burst their sheaths at an age of three or four weeks, 

 but the wings are not fully grown until the bird is eight or nine weeks 

 old. In my captive bird, the head, neck, and under parts were still 

 largely downy at an age of 14 weeks; and the full plumage was not 

 acquired until the bird was more than 20 weeks old in September. 



This first winter plumage is much like that of the adult but is 

 somewhat more rufous throughout, the ear tufts are smaller, the white 

 throat patch is less extensive and not such pure white, and more or 

 less of the downy plumage persists for some time about the neck and 

 lower under parts. It is worn for ten months or so, until the next 

 annual molt, the first postnuptial. Adults apparently have only one 

 complete annual molt in summer and fall. 



Food. — The great horned owl is a ravenous feeder on a great variety 

 of animal life, and a very generous provider for its hungry young; 

 almost any living creature that walks, crawls, flies, or swims, except 

 the larger mammals, is its legitimate prey; it is not at all particular 

 as to what it kills for food and will take what is most available and 

 most easily caught. It is so powerful and aggressive that it can 

 attack and kill surprisingly large mammals or birds. Where its vic- 

 tims are plentiful it often kills much more than it needs, eating only 

 the choicest parts, but where food is scarce it often returns again and 

 again to its kill. 



I believe that it prefers to feed on the smaller mammals, mainly 

 those that are active at night, as these are more readily available 

 and easier to catch in its favorite haunts than are birds and poultry; 

 where these are sufficiently numerous, they make up the bulk of the 

 food of this owl. The fist of mammals taken includes hares and 

 rabbits of various species, gray, red, flying, and fox squirrels, chip- 

 munks, various rats and mice, including our destructive house species, 

 muskrats, ground squirrels, pocket gophers, spermophiles, minks, 



