156 BULLETIN 16 7, UNITED STATES NATIONAL MUSEUM 



are heavily streaked or spotted with a dark sepia, suggesting the 

 adult pattern. This plumage is worn throughout the first winter 

 with little change except by wear and fading, the buffs being replaced 

 by dull white. 



A complete molt from the ju venal into the adult plumage begins 

 very early in the spring, is very gradual, and is prolonged through 

 the summer or into the fall, with much individual variation. I have 

 seen a young bird with new red feathers in its tail in February, and 

 birds with missing flight feathers are often seen during the nesting 

 season. At the completion of this molt in fall young birds are prac- 

 tically indistinguishable from adults. Young birds raised in cap- 

 tivity have molted from the juvenal into the red-tailed adult plum- 

 age when a little over a year old. I have examined a large series of 

 eastern birds and have not been able to recognize a second-year 

 plumage, such as seems to occur in harluni; immature specimens of 

 caluims often have reddish tails with numerous narrow black bars; 

 these are probably first-year birds with erythristic tendencies. Nei- 

 ther erythrism nor melanism seems to occur in eastern birds, but 

 cases of nearly, or quite, perfect albinism have been reported. Adults 

 have one complete annual molt, which may begin in spring or early 

 in summer and may be completed in September or October. 



Food. — It is generally conceded that the red-tailed hawk is a highly 

 beneficial species, as its food consists mainly of injurious rodents 

 and as it does very little damage to domestic poultry or wild birds. 

 Dr. A. K. Fisher (1893) writes: 



Of 562 stomachs examined by the author, 54 contained poultry or game birds ; 

 51, other birds; 278, mice; 131, otlier mammals; 37, batrachians and reptiles; 

 47, insects ; 8, crawfish ; 13, offal ; and 89 were empty. It has been demon- 

 strated by careful stomach examination that poultry and game birds do not 

 constitute more than 10 per cent of the food of this Hawk, and that all the 

 other beneficial animals preyed upon, including snakes, will not increase this 

 proportion to 15 per cent. Thus the balance in favor of the Hawk is at least 

 85 per cent, made up largely of various species of injurious rodents — a fact 

 that every thoughtful farmer should remember. * » * 



The increase of any animal is always followed by a relative increase of its 

 natural enemies. This is clearly shown on the river front in the vicinity of 

 Washington, D. C, where the recent improvements have redeemed several hun- 

 dred acres of ground from the tidal flats; and already in many places rank 

 vegetation has grown up, affording shelter and sustenance for hordes of mice. 

 At present in winter and early spring it is not uncommon to see ten or fifteen 

 Red-tailed Hawks in different parts of this flat attracted hither by the abun- 

 dance of their natural food. Prior to the reclamation of the flats not more than 

 a pair or two were to be seen in the same neighborhood during the winter. 



Of 173 stomachs of this hawk examined by Dr. B. H. Warren 

 (1890) in Pennsylvania, 131 contained the remains of mice, 6 of 

 rabbits, 3 red squirrels, 2 skunks, 18 small birds, 14 poultry, 3 in- 

 sects, 3 snakes, and 4 offal or carrion. He says: "I have repeatedly 



