NORTH AMERICAN BIRDS. 181 



and approaches the Owls in the habit of hunting by twilight. Its food 

 consists chiefly of mice and frogs. 



The nest of this species is placed on large trees, frequently on 

 ledges of rocks ; it is a bulky structure, composed of sticks, grasses, 

 weeds and various other materials which are soft and easily matted 

 together. The eggs are two or three in number ; they are white or 

 buffy, sprinkled, spotted or blotched with brown ; the average size given 

 is 2.27x1.76. Mr. Norris has a set of two eggs taken June 9, 1864, on 

 the Anderson River, in Arctic America, by R. R. MacFarlane. These 

 are of an ivory white, spotted, splashed and blotched with cinnamon ; 

 they measure, 2.20x1.76, 2.22x1.81. 



348. ArcMbuteo ferrugineus. (Light.). [448.] 



Ferruginous Rough-leg. 



Hab. Western United States, across the great plains, north to the Saskatchewan region; south to 

 Mexico. Occasionally to Illinois. 



Known as the Ferruginous Rough-legged Buzzard or California 

 Squirrel Hawk. A common species on the plains of the West, and one 

 of the largest and handsomest of our American Hawks. 



In some localities this species builds its large and bulky nests on 

 trees, ranging from ten to fifty feet from the ground ; it is composed of 

 large sticks and lined with leaves, tufts of grass and roots. Mr. F. M. 

 Dille, of Greeley, Colorado, states the birds are not shy, and made no 

 demonstration when he approached the nest. He describes a nest as 

 measuring three feet in diameter and two in depth. The eggs are two 

 or three, rarely four, in number. 



Capt. B. F. Goss informs me that he found this Hawk in Northern 

 Dakota nesting on the ground, on rocky, precipitous hillsides ; this, too, 

 being the case seemingly from choice, for heavy timber was only a few 

 miles awa}^, and patches of brush and low trees were often in the im- 

 mediate vicinity of the nest. May 4, 1884, Capt. Goss found a nest at 

 the foot of a rock, on a steep bluff; it was composed of sticks, buffalo 

 ribs, weed stalks and small pieces of turf, lined with dry grass. Four 

 eggs, vary greatly in color, from finely spotted to heavily splashed 

 with different shades of brown; sizes, 2.44x1.96, 2.55x1.96, 2.45x2.00, 

 2.40 X 1.92. Mr. Dille states that the usual date for depositing the eggs 

 on the plains af Colorado is about May 20, but he has taken fresh 

 eggs as early as April 20. A set of two in Mr. Norris' collection, 

 taken in Comal county, Texas, March 30, 1873, are spotted, splashed 

 with brown and burnt umber. They measure 2.33x1.88, 2.34x1.86. 



