1936 THE OWLS 



bone or metatarsus; which has the bony bridge over the hollow at the upper end, 

 and likewise in the general form of the lower end of the tibia,* although the latter 

 retains the bony bridge which has been lost in the owls. Moreover, the osprey 

 agrees with the owls, and thereby differs from the typical diurnal birds of prey, by 

 the absence of a distinct aftershaft to the feathers. In the present group the nos- 

 trils are not concealed by bristles, and the toes are naked, and furnished beneath 

 with spicules like those of the fish owls. The osprey, or fishing hawk, is the sole 

 representative of its genus, and is characterized by the length of its wings, and 

 naked and rather short metatarsus, which is entirely covered with reticulate scales. 

 In length the osprey varies from twenty-two to twenty-four inches. In color, the 

 beak is black, the cere blue, and the iris yellow. The elongated feathers at the 

 tip of the head and nape of the neck are whitish, streaked with brown; the upper 

 surface of the body and wings is dark brown, with the ends of the primaries black, 

 and that of the tail two shades of brown. Beneath, the chin and throat are white, 

 the upper part of the latter being marked with a pale brown band, while the abdo- 

 men, thighs, and under tail coverts are also white. The wing is partly white and 

 partly brown beneath, and the lower surface of the tail is white, barred with gray- 

 ish brown. The legs and toes are blue. 



Following the views of most English writers, that there is but a single repre- 

 sentative of the genus, the osprey has an almost cosmopolitan distribution, although 

 it is unknown in the extreme south of South America, as well as in parts of 

 Oceania. In England it is a rare summer visitor, but it used formerly to breed in 

 many parts of Scotland, where it is now well-nigh exterminated. For nearly a cen- 

 tury a pair have, however, bred at Loch-an-Eilan Castle. In 1890 three birds 

 appeared at the nesting place, one of which, after a fierce encounter, was killed, 

 whereupon the others disappeared. In 1891 a pair again visited the district, but 

 instead of taking up their old quarters, selected Loch Merlich some miles distant 

 as their abiding place. Here they were unfortunately disturbed, but in 1892 

 they once more reappeared at I^och-an-Eilan, where effective measures have been 

 taken to secure them from molestation. The osprey feeds almost exclusively on 

 fish, which it captures both at sea and in fresh waters, and it is doubtless for the 

 purpose of holding its slippery prey that the fourth toe is reversible, and the soles 

 of the feet covered with spicules. Sir J. Richardson writes that " when looking out 

 for its prey, it sails with great ease and elegance, in undulating and curved lines, at 

 a considerable altitude above the water, from whence it precipitates itself upon its 

 quarry, and bears it off in its claws; or it not unfrequently, on the fish moving to 

 too great a depth, stops suddenly in its descent, and hovers for a few seconds in the 

 air, like a kite or kestrel, suspending itself in the same spot by a quick flapping of 

 its wings; it then makes a second, and, in general, unerring dart upon its prey, or 

 regains the former altitude by an elegant spiral flight. It seizes the fish with its 

 claws, sometimes scarcely appearing to dip its feet in the water, and at other times 

 plunging entirely under the surface, with force sufficient to throw up a considerable 

 spray. It emerges again, however, so speedily as to render it evident that it does 

 not attack fish swimming at any great depth." 



* I have not had the opportunity of examining the leg bones of Polioaetus. 



