220 BULLETIN 16 7, UNITED STATES NATIONAL MUSEUM 



come more extensively rufous, "cinnamon" to "orange-cinnamon"; 

 the tail and rump become whiter; the under parts become whiter, 

 finally including the throat and chin; and the dusky barring disap- 

 pears, or becomes very faint, except on the flanks. 



I have been unable to trace the molts, as I have seen no summer or 

 fall specimens. Probably a complete annual molt occurs during that 

 time. 



Food. — Mr. Burrows (1917) writes: "This species feeds upon rab- 

 bits and wood rats, in fact I have found that its diet is largely con- 

 fined to rabbits which are found in immense numbers in that section. 

 If the nest contains young birds it is sure to show that they are 

 amply provided for by the amount of fur and the number of rabbits' 

 feet found in and about the nest. * * * j }iave never found any 

 evidence that they feed at any time upon other birds." 



Other observers have noted cotton rats, quails, snakes, lizards, 

 frogs, grasshoppers, and beetles among the food of this hawk. 



Behavior. — Mr. Burrows (1917) says of the behavior of the white- 

 tailed hawk near its nest : 



The bird will always leave the nest while the intruder is quite a distance 

 away, often at a distance of a quarter of a mile, for as I said above the nest 

 commands a broad expanse and the bird is always on the watch. When the 

 female leaves the nest, the male bird usually joins her at once and the two 

 often disappear and do not come in sight while the nest is being examined ; 

 at other times they mount high in the air, far above the reach of a shotgun 

 and directly above the nest, where they will often stand poised in one spot 

 for several minutes at a time coolly watching development below. At such a 

 time the birds always face the strong sea breeze which blows so steadily and 

 strong that it is possible for them to appear perfectly motionless and stand 

 suspended in mid-air. 



Voice. — Burrows says on this point : "The note is peculiar, some- 

 what like that of Cooper's Hawk when disturbed at the nest, but in 

 a much higher key and with a tinkling, musical sound. It consists 

 of the syllables ke-ke-ke-ke-ke-ke-ke repeated many times," 



Dr. Merrill (1879) thought the cry sounded "much like the bleat- 

 ing of a goat." And Mr. Brandt says in his notes : "The call of the 

 female was not a Buteo-like scream, but an uttered cut-a^ cut-a^ 

 cut-a., resembling very much the call of the laughing gull." 



Field marks. — Mrs. Florence M. Bailey (1916) notes these very 

 prettily as follows : 



When opportunity afforded I noted eagerly its immaculate breast, whit© 

 rump, and white tail with black subterminal band; but the impression of the 

 bird is what is recalled to-day when a level prairie comes to mind. At a dis- 

 tance one sees a large statue of a Hawk on the prairie floor; on nearer ap- 

 proach, a King of Hawks looking up with calm enquiring gaze, both gaze and 

 pose bespeaking the silent power of the race. The white of the Hawk, by Mr. 



