270 BULLETIN 16 7, UNITED STATES NATIONAL MUSEUM 



seen two of these birds, probably a pair, circling together to a con- 

 siderable height and then striking out in direct flight for the 

 northeast. 



As is the case with most hawks, migration of considerable num- 

 bers of this bird may sometimes be observed in the spring. E. A. 

 Doolittle (1919) records a flight of 100 broad-winged hawks with 

 about 20 roughlegs in Lake County, Ohio, on April 27, 1919. He 

 says : "All the roughlegs were sailing with the wind and flying in a 

 straight northeasterly direction, while the broad-wings kept in 

 bunches and circled about to some extent while still progressing 

 steadily in the same direction." 



[Frank L. Farley writes to me that on his arrival at Churchill on 

 June 7, 1936, large numbers of these hawks, perhaps a hundred or 

 more a day, were passing in migration ; this migration had evidently 

 been going on for some time, for he found six nests with eggs during 

 the following week. He says: "I should say that at least 1,000 of 

 these hawks must have quietly passed over our camp during the first 

 10 days we were there ; they all seemed to be quartering the territory, 

 always watching for lemmings; they would not make more than a 

 mile or two in a half hour ; when one would come to the edge of the 

 Churchill River, it would at once drop down to an elevation of not 

 more than 50 feet above the water and fly directly to the other side ; 

 at other times, while hunting, they would be several hundred feet 

 high. The entire migration seemed to move up the coast in a narrow 

 strip, not more than a quarter to half a mile wide; they generally 

 traveled separately, but most of them would usually be within sight 

 of those ahead of them."— A. C. B.] 



Courtship. — The courtship of this hawk appears to be performed 

 in the air, as is the case wdth the marsh hawk. I have on several 

 occasions seen two roughlegs in the spring soar upward close to- 

 gether, emitting their characteristic notes, a combination of musical 

 whistles and hisses, and I have thought that this was part, perhaps 

 the principal part, of their courtship. Henniger and Jones (1909) 

 speak of these birds "circling high and playing with the wind in 

 mating season." 



Nesting. — The rough-legged hawk in its nesting habits is gov- 

 erned by its surroundings. On the bleak and treeless shores of Lab- 

 rador this bird nests on the higher shelves of the cliffs and preferably 

 on the tops of the cliffs. In forested regions, however, the nest is 

 built in trees near their tops. But even in these forested regions a 

 steep river bank of shelving rock often tempts the bird to place the 

 nests here. Henniger and Jones (1909) state that the birds sometimes 

 nest in "hollow trees, in crevices of rocks, in holes of river banks 

 and in buildings." 



