140 
FALCON 1 FO R M ES 
One of our commonest hawks found almost anywhere in Canada. 
It haunts the open marshes, meadows, and fields and is to be seen beating 
up and down, quartering and covering the ground like a well-trained bird- 
dog. For an instant it hovers over its intended prey and then drops 
upon it, rising a moment later to alight on a fence-post or other similar 
slight elevation to devour its captive. The young are unsuspicious, but 
the blue adults are amongst the wariest of birds and fall to the gun com- 
paratively seldom. 
Economic Status. Of 116 stomachs examined: 7 contained poultry 
or game-birds; 34, other birds; 57, mice; 22, other mammals; 7, reptiles; 
2, frogs; 14, insects; and 1, indeterminate matter. Thus of 144 food 
items 41 were harmful, 93 useful, and 10 neutral. Of the 41 harmful 
items, only 3 were domestic fowl, and the remainder wild stock, consisting 
of 46 individuals of considerably less value than the domestic varieties. 
The mice and other mammals included about 117 individuals. The 
insects were mostly locusts, grasshoppers, and beetles. The balance 
is evidently in favour of this species, which is incapable of taking any 
fowl but small ones and then only when they wander into its habitat. 
Keeping spring chickens close about the premises is an almost perfect 
protection against this bird. Haunting marshes, grassy meadows, and 
tangled dry sloughs, as it does, it is the natural enemy of field-mice and 
probably does as much to keep their numbers within bounds as any other 
single natural influence. 
Probably on the whole, and certainly in strictly agricultural country, 
the Marsh Hawk is considerably more beneficial than harmful. For a 
few weeks in early summer, when the marshes throng with small ducks 
and the young Prairie Chickens are on the uplands, it often engages in ques- 
tionable pursuits and considerable numbers of half-grown game-birds 
become its prey. However, as soon as these immatures become too large 
and sturdy for so light a raptore to handle, it once again turns to mice and 
lesser game. Except where game is the most valuable crop, its presence 
is to be encouraged and shooting resorted to only where its depredations 
are particularly serious. 
Subfamily — Pandioninae. Ospreys 
The Fish Hawks or Ospreys constitute a sub-family of raptorial birds 
subsisting entirely upon fish, which they capture in shallow water by 
diving. Other members of the order eat fish, but usually only as scavengers 
or by stealing from fish-catching birds. As there is only one species of 
Fish Hawk in America, no general discussion of the family is necessary 
here. 
364. Osprey, fish hawk. l'aigle-p£;cheur (l’Orfraie). Pandion haliaeetus. 
L, 23*10. Plate XVI A. A very large, dark brown (nearly black) and white hawk, very 
white below without other markings than sometimes a vague, disconnected band of 
suffused, light brown spots across the breast. 
Distinctions. A large brown and white hawk, with pale blue feet, the soles of which 
are covered with sharp, horny processes for grasping slippery fish (Figure 206). Head, 
largely white with contrasting black ear coverts, anti a loose crest of white, dark-tipped 
feathers, from the hindhead. 
Field Marks. A very large hawk (Figure 174 — 3), very white below, with a long wing 
expanse, almost eagle-like in outline, but with wing tips less broadly rounded (Figure 20S). 
