AMERICAN ROUGH-LEGGED HAWK 279 



from below the black patches near the wrist joints in the ^^•hite of 

 the lower surface of the Avings, the black tips to the primaries and 

 secondaries, and a broad black bar across the upper belly are all 

 good field marks. The heavily feathered tarsi may often be made 

 out as the bird drops its feet preparatory to a sv.oop. The white 

 rump as well as the habit of quartering the ground might suggest a 

 marsh hawk, but the smaller size of the marsh hawk, its slenderer 

 form, narrower wings, and longer tail in proportion make the dis- 

 tinction an easy one. 



To recognize the roughleg in the field one must take into consider- 

 ation the great variations in its plumage. In the extreme dark 

 phase it may appear as black as a crow both above and below, and 

 it then lacks the white rump and other field marks. There is, how- 

 ever, generally some white to be seen in the wing feathers from be- 

 low and some barring in the tail and, except in the extreme dark 

 phase, a little white on the rump. In the light phase I have seen a 

 bird with the white extending in the tail to within a short distance 

 of the tip so as to give the effect of a white tail with a black ter- 

 minal band. The dark band across the upper belly in the light 

 phase, such a good field mark, is sometimes entirely lacking. In 

 my notes I find records of 25 different roughlegs seen in the field in 

 eastern Massachusetts where I recorded the plumage phases. Eight 

 of these were in the dark phase, 12 in the light phase, and 5 inter- 

 mediate (C. W. Townsend, 1920). 



Fall. — The migration from the breeding grounds in the north 

 depends on the snow fall. The earlier it comes, the earlier the birds 

 migrate, and as the snow advances the hawks keep ahead of it, so 

 that they can obtain their rodent food. I have seen this hawk at 

 Ipswich as early as October 12, but the last days of the month are 

 its usual time of arrival. Widmann (1907) gives November 1 for 

 their arrival in Missouri. Singly or by twos or threes, the birds 

 sometimes migrate in great numbers together. Fleming (1907) re- 

 corded an immense flight of rough-legged hawks in October 1895 

 at Toronto; "from the 26th to the 29th the birds were taken in 

 dozens; I must have had over fifty brought to me in that time." 

 Mr. Fleming, in a recent letter, states that besides these well over 50 

 more were mounted b}^ taxidermists. "How many v*^ere killed at 

 Toronto it is impossible to saj'^, but it was in the days of flight shoot- 

 ing of hawks. They drifted westerly along the ridge that rises 

 behind the city, and it was the custom for gunners to wait for them 

 there. The 1895 flight was the greatest we have ^\\y knowledge of. 

 and it was followed by a lesser one in 1896." 



Enemies. — What these hawks may suffer from external parasites is 

 well shown in the following report by T. T. and E. B. McCabe 



