790 Report of State Geologist. 



sented the extreme of the black phase. They frequented tlie meadows, 

 pastures and stubbles, where they fed upon the mice, which were so 

 common that winter. They appear in the -vicinity of Chicago from 

 the middle to the last of October and in Knox County, Ind., from the 

 1st to the 20th of November. Some years they leave in February, 

 but usually they remain well into March, sometimes to about April 1. 

 March 12, 1887, Mr. E. L. Guthrie, of Adams, sent me one of six. or 

 seven noted in that vicinity. He said their principal food was mice, 

 but he discovered one a few days before, feeding on the carcass of 

 a dead lamb. Another person saw one eating the carcass of a dead 

 skunk. The stomachs of six examined by me that winter contained 

 nothing but mice and one rabbit. The summary of the report of the 

 investigations made under the direction of Dr. Merriam, of the United 

 States Department of Agriculture, shows that of 49 stomachs ex- 

 amined, 40 contained mice; 5, other mammals; 1, lizards; 1, insects; 

 and 4 were empty. It is known also, at times, to eat grasshoppers 

 extensively. It sits upon a low perch and watches for its prey, and 

 also sweeps the meadow, prepared to seize a mouse, when it appears. 

 They vary much in color, ranging from very light to nearly uniform 

 black. Whenever they are with us they are valuable friends of the 

 farmer. So far as we know, there is not a harmful thing they do. 

 They are wholly beneficial. They breed far north, in trees, or upon, 

 cliffs. The eggs are deposited at intervals of two or three days. In- 

 cubation apparently begins before all are laid, and lasts about four 

 weeks. One brood is raised a year. This Hawk is said to be of a very 

 peaceful disposition, and soon becomes accustomed to permitting jtself 

 to be handled after a few days' captivity. 



76. Grnus AQUILA Brisson. 



139. (349). Aquila chrysaetos (Linn.). 



Oolden Eagle. 



Legs, densely feathered down to base of toes. This character will 

 separate it, in any plumage, from the White-headed Eagle, which is 

 the only other Eagle in the United States. 



Length, 30.00-40.00; wing, 23.00-27.00; tail, 14.00-16.00. (Fisher). 



Range. — Northern portions of Northern Hemisphere; south in 

 North America to southern California, Mexico and Georgia. Breeds 

 chiefly in mountainous regions throughout its range. " 



Nest, on cliffs, sometimes in trees; a collection of sticks. • Bg'gg, 

 2-3; whitish, sometimes unmarked, usually more or less lilotched, 

 spotted or clouded with various shades of brown; 2,93 by 2.:^1. 



