RAPTORIAL BIRDS 
113 
complaint can be lodged against them. Of the Diurnal and Nocturnal 
Rapaces, their mixed status is the cause of much misconception. Fortun- 
ately in regard to these birds we can speak with authority based upon 
actual data and not mere speculation. The United States Biological 
Survey made a thorough study of the food habits of American hawks 
and owls, basing its conclusions upon the examination of about 2,700 
stomachs taken in all seasons of the year in various parts of the United 
States and Canada. The whole, with the data for its substantiation, 
is embodied in a report, “The Hawks and Owls of the United States,” 
by Dr. A. K. Fisher. 1 Although compiled in and for an adjoining country 
all Canadian species are treated, and the results are as applicable to Canada 
as to the United States. As some of the less harmful species do not occur in 
Canada the following percentages should be slightly altered for our use, 
but not enough to modify perceptibly the general conclusions. Only 
six of the seventy-three species studied are injurious. Of these, three are 
extremely rare in Canada, and one is altogether a fish-eater. Of the 
remainder, 56 per cent of the stomachs examined contained mice and other 
small mammals, 27 per cent insects, and only 3| per cent poultry or game- 
birds. Dividing the thirty-three raptorial birds of western Canada into 
groups according to their economic status we find that four species are 
wholly beneficial and absolutely harmless; seventeen are mainly beneficial, 
doing decidedly more good than harm; six are about balanced in their 
effect ; and six are positively harmful. Only three of these six are common 
enough to warrant consideration and only two, the Sharp-shinned and 
Cooper’s Hawks, are numerous enough in the thickly settled communities 
to be noticed. The Goshawk is a more northern species whose distribution 
overlaps the edges of settlement on the north or in the mountains. 
In making these generalized estimates, it should be understood that 
they are based on averages of the whole country throughout the year. 
Local conditions, time of year, and the particular interests of the locality 
may modify the conclusions. For instance, the Red-tailed Hawk, in 
summer time on the open prairie, is just as efficient and indefatigable a 
gopher killer as the Ferruginous Rough-leg; in the autumn when gophers 
have holed up, and the young, inexperienced hawks are seeking easily 
captured prey, game and poultry may in some cases suffer slightly from 
their attack. The Bald Eagle is only a rare picturesque feature of the 
landscape over most of Canada, but on the coasts it is often seen in greatly 
increased number and may be a serious enemy of water-fowl. The Marsh 
Hawk is an inveterate mouser, but in early summer the abundance of 
young upland and marsh game has attractions for it. Just where to draw 
the line between generally beneficial and harmful species is thus sometimes 
difficult to decide. 
Raptorial birds, like human beings, tend to subsist on that which is 
first to hand, and a generalization based on one set of conditions will not 
always hold good for others. It is a natural psychological fact that we 
ourselves feel a definitely known, concrete loss more keenly than we do 
a much greater one that we have unwittingly escaped. The loss of a single 
partly grown chicken to hawks is more keenly realized than the absence 
of some hundreds of gophers that never intruded themselves upon our 
consciousness. The one fact is taken as a calamity, the other as a matter 
! See also "The Hawks of the Canadian Prairie Provinces in Their Relation to Agriculture”; Geol. Sur% r ., 
Canada, Mus. Bull. 28 <1‘J18). 
