48 BIRDS OF PREY. 
ceived and soon followed by his ambitious mate, and in a little 
time, by circular ascending gyrations, they both disappeared in 
the clear azure of the heavens; and though I waited for their 
re-appearance half an hour, they still continued to be wholly 
invisible. This amusement, or predilection for the cooler 
regions of the atmosphere, seems more or less common to all 
the rapacious birds. In numerous instances this exercise must 
be wholly independent of the inclination for surveying their 
prey, as few of them besides the Falcon descend direct upon 
their quarry. Many, as well as the present species, when on 
the prowl fly near to the surface of the ground, and often wait 
and watch so as to steal upon their victims before they can 
take the alarm. Indeed the Condor frequents and nests upon 
the summit of the Andes, above which they are seen to soar 
in the boundless ocean of space, enjoying the invigorating and 
rarefied atmosphere, and only descending to the plains when 
impelled by the cravings of hunger. 
The Eastern variety of the Red-tail is a common bird through- 
out eastern North America north to about latitude 49°, and was 
taken by Dr. Bell at Fort Churchill, on Hudson’s Bay. It ranges 
westward to the Great Plains, where it is replaced by the sub- 
species kriderz. From the Rocky Mountains to the Pacific it is 
represented by caduzus, and examples of this latter variety have 
been taken, occasionally, as far east as Illinois. The Red-tail is a 
summer resident only of the Maritime Provinces, but a few are 
found in winter in southern Ontario and New England. 
Note. — Mr. Ridgway now considers HarLANn’s Hawk to be 
a variety of the Red-tail, and he proposes to name it Budeo borealis 
harlanz. Its usual habitat is along the lower Mississippi; but exam- 
ples have been taken in Illinois, Iowa, Pennsylvania, and Georgia. 
Two examples of SwarInson’s Hawk (Buteo swainsonz), a 
Western species, have been taken in Massachusetts, —one at 
Wayland in 1876, and the other near Salem in 1878. 
