BIRDS OF PENNSYLVANIA. 131 



take aliment in the way described. I incorporate it, notwithstanding 

 that it disagrees with certain good authority. 



Nest-building- takes place from the first to the middle of May, and the 

 four nests which I have found have all been located in high trees ; three 

 in hickory trees, the other in an oak. All of these nests were over fifty 

 or sixty feet from the ground. The nest is very similar to that of the 

 Cooper's Hawk ; it is made of sticks, twigs, leaves and rootlets, lined 

 with feathers ; one I found lined with bark. The complement of eggs 

 is usually four, although three sometimes is the full set. The eggs are 

 somewhat larger than those of the Cooper's Hawk, with a dull white, 

 grayish ground color, with brownish red spots, which vary in size from 

 specks to large patches, frequently confluent. 



This hawk is generally easily captured, appearing quite tame and un- 

 suspicious. I have always found it to be cowardly, and to evince no 

 disposition to repel an invasion of its nest. 



It would seem, however, that the disposition of this bird, under cer- 

 tain circumstances, is very variable. Mr. A. G. t Boardman, of Maine, 

 who has found several nests, and secured the eggs, finds it to be cour- 

 ageous and spirited. A man whom he had employed to obtain a nest, 

 was attacked with great fury, while ascending the tree ; his cap was 

 torn from his head, and he would have been seriously injured if the bird 

 had not been shot. Another instance is mentioned by Dr. Wood, where 

 this hawk attacked a boy climbing to her nest, fastened her talons in 

 his arm, and could not be removed until beaten off and killed with a club. 



In speaking of this bird, Dr. Wood says : " Seldom, if ever, does it 

 seize its prey on the wing, but secures it mostly on the ground, subsist- 

 ing on frogs, snakes, mice and small birds, devouring the latter without 

 removing the feathers. This hawk in its habits is not as neat in pre- 

 paring its food as most of its genus ; holding its prey with both feet, it 

 tears and eats without much regard to cleanliness or feathers." 



In twelve specimens examined by myself, four revealed mice ; three, 

 small birds; four, frogs; one, killed the 22d of May, 1882, was gorged 

 with cray -fish, with which were traces of coleopterous insects (beetles). 



GENUS ARCHIBUTEO BREHM. 

 Archibuteo lagopus sancti-johannis (GMEL.). 



American Rough-legged Hawk ; Black Hawk. 



DESCRIPTION. 



" Adult male and female : Too variable in plumage to be concisely described. In 

 general, the whole plumage with dark brown or blackish and light brown, gray, or 

 whitish, the lighter colors edging or barring the individual feathers; tendency to 

 excess of the whitish on the head, and to the formation of a dark abdominal zone or 

 area which may or may not include the tibiae ; usually a blackish anteorbital and 



