130 
FALCONIFORMES 
Nesting. A bulky nest of sticks in trees. 
Distribution. Western North America. In Canada, from Manitoba westward to the 
coast, north to the tree limit. Most common on the prairies. Migrates to South America. 
It is our only hawk that regularly retires entirely from the North American continent in 
winter. 
Swainson’s is the common hawk of the prairies. Nearly all the larger 
bluffs and most of the wooded coulees contain one or more nests from 
which the birds beat out over the cultivated and waste places carrying 
destruction into the ranks of ground-squirrels and gophers. Though the 
Red-tailed Hawk may take an occasional chicken or grouse, instances 
of Swainson’s Hawk doing so are unusual enough to cause surprise. It 
varies its rodent food with grasshoppers caught on the ground with clumsy 
gravity, making heavy hops with waving wings and short runs hither and 
thither as it grabs the nimble insects with talons that look absurdly big 
and formidable for the purpose. Though its effect on insects is not to be 
disregarded, its highest usefulness is obviously directed against small 
mammal pests. Early and late it is at work supplying its own needs and 
those of its hungry offspring, and the number of gophers consumed by 
a single family of this hawk throughout the season reaches an important 
total. The prairie farmer can scarcely raise better paying stock than a 
few broods of Swainson’s Hawks. The value of this system of gopher 
control is that it is always working and is not confined to the premises that 
are kept clear of vermin by dint of the owner’s efforts, but is spread over 
those of his more careless neighbour whose land is a constant source of 
reinfestation to surrounding localities. 
Rough-legs 
The Rough-legged Hawks are buzzards principally characterized by 
having legs feathered to the base of the toes (Figure 190). They are hawks 
Figure 190 
Feathered tarsus of Ferruginous Rough-legged Hawk; 
scale, 
of the very largest size, but their feet are comparatively small and weak 
for so large a bird, and they are obviously too lightly armed for attack on 
vigorous prey. They restrict their diet to small mammals and insects, 
being particularly efficient grasshopper destroyers. They obtain their 
name from the “rough” or feathered tarsus. There are two species of 
Rough-legs in Canada, one nesting commonly in the southern prairies, 
the other a summer inhabitant of the far north, passing through settled 
Canada only on migration. Both species are dichromatic and occur in 
light and dark phases with intermediate plumages. 
