92 BIRDS OF PENNSYLVANIA. 



GENUS ARCHIBUTEO. BREHM. 

 347 a. Archibuteo lagopus sancti-johannis (GMEL.). 



American Rough-legged Hawk. 



DESCRIPTION. 



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

 general, the whole puinage 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 tibise ; usually a blackish anteorbital and 

 maxillary area. Lining of wings extensively blackish. Tail usually white from 

 the base for some distance, then with dark and light barring. The inner webs of the 

 flight feathers extensively white from the base, usually with little, if any, of the 

 dark barring so prevalent among buteonine hawks. From such a light and vari- 

 egated plumage as this, the bird varies to more or less nearly uniform blackish, in 

 which case the tail is usually barred several times with white. * * Length of a 

 female, 22.00; extent, 54.00; wing, 17.50; tail, 9.00; iris light brown; bill mostly 

 blackish-blue, cere pale greenish-yellow, feet dull yellow, claws blue-black. This 

 is about an average size ; the male averages smaller." Cone's Key. 



Hab. Whole of North America north of Mexico, breeding chiefly north of the 

 United States. 



In any plumage this bird can easily be distinguished from other of 

 our hawks by the tarsus, which is thickly feathered in front to the 

 toes. I have found the Rough- legged or Black Hawk in Pennsylvania 

 only as a winter sojourner, about the meadows and grass fields along 

 or near large streams. In the winter of 1879, when hunting along the 

 Brandywine creek, I saw seven of these hawks at one time, perched 

 about on trees in a meadow of some five acres in extent. In this lo- 

 cality, the species is usually found singly or in pairs. The Rough- 

 legs generally migrate northward about the middle of March ; I have, 

 however, observed them here late in April. " Its migrations appear 

 to be quite regular and extensive more so, perhaps, than is generally 

 supposed though probably it does not diifer from most Hawks in this 

 respect. Birds of this family must follow their prey, wherever this 

 leads them, and only a few of the more powerful species, able to prey 

 upon hares and Ptarmigan, pass the winter in our highest latitudes. 

 The Rough-legged is a rather northerly species, rarely, if ever, breed- 

 ing within the limits of the United States, and becoming rarer to- 

 wards its southern terminus." Coues. Although this Hawk usually 

 breeds north of the United States, or at least is generally so recorded 

 by various writers, it occasionally nests as far south as Pennsylvania. 

 April 5, 1886, Mr. Samuel B. Ladd, of West Chester, Pa., found a nest 

 and two eggs of this bird, in a thick woods, at Fites Eddy, on the 

 Susquehanna river. Mr. Ladd has kindly furnished me with the fol- 

 lowing description of this nest and eggs: "The nest, partly con- 

 cealed by a wild grape vine, was built in the crotch of an oak tree, 



