276 BULLETIN 16 7, UNITED STATES NATIONAL MUSEUM 



Behavwr. — As a rule the rough-legged hawk is an unsuspicious 

 bird and can be more easily approached than most hawks. Par- 

 ticularly is this the case when the observer is mounted or in a car- 

 riage or automobile. Turner says in his Ungava notes : "At no time 

 did I observe anything of a fierceness exhibited by these birds either 

 when wounded or when their nest was approached. The male can 

 seldom be secured near the nest, while the female is sometimes heed- 

 less of distance although rarely approaching very near." Their mild 

 disposition is shown even by adults that have been tamed soon after 

 being taken into captivity. 



In nesting they maintain certain territorial rights; thus H. B. 

 Bigelow (1902) found them very common in the cliffs of northern 

 Labrador and "different pairs of hawks seemed to hold different 

 tracts of country from which they drove all intruders." Charles A. 

 Gianini (1917) found in Alaska that "evidently there is mutual re- 

 spect between them and the bald eagle, for I have seen their nests 

 on cliff's in close proximity to each other." They fly about their nest 

 in great concern, scream loudly when a man approaches, so it is 

 generally very easy to find the nest. 



The flight of the rough-legged hawk, although generally slow and 

 leisurely, is graceful and indicative of skill and power. In soaring, 

 the wings and tail are spread to their full extent; the first half-dozen 

 primaries are spread out separately like fingers and curve upward 

 at their tops. On motionless wings, if the air currents are favor- 

 able, this bird may often be seen soaring high over the land rising 

 higher and higher until it becomes a mere speck in the sky. 



In searching for mice they often fly slowly, alternately flapping 

 and sailing, close to the ground or even 50 yards up in the air. They 

 often quarter the ground like marsh hawks or harriers, frequenting 

 open fields and pastures and marshy places. I once saw one swoop- 

 ing down over the frozen surface of a pond and closely skimming 

 it. Either the bird mistook the ice for water and was looking for 

 swimming rodents or surface fish or else it was merely indulging in 

 play. It is not uncommon to see this hawk skimming close to the 

 surface of water, and one I watched in February at Ipswich flew 

 from the region of the dunes over the sea, swooping down for a 

 moment close to the waves at the bar. The vicinity to water seems 

 always to attract this species. 



They frequently hang in one place by rapid vibration of the wings, 

 turn the head from side to side in looking down, and often drop 

 their long-feathered tarsi preparatory to pouncing on the prey, only 

 to draw them up behind when they change their mind. At other 

 times, when luck is propitious, they partially close their wings and 

 drop like a plummet. On one such occasion at Ipswich, Mass., in 

 winter I saw the hawk fly off with a large mouse to the salt marsh, 



