Birds and Birding's Guide to:

Watching THE FALCON-LIKE BIRDS

THE KITES, BUZZARDS, EAGLES, HAWKS, AND ALLIES

The Ospreys

(Subfamily Pandionince.)—There has been a great deal of discussion as to the proper systematic position of the Ospreys (Pandion), and even now their status can hardly be regarded as definitely settled.

From the fact that they possess a more or less reversible outer toe, and also certain peculiarities in the skeleton, they were long held to exhibit a more or less distinct transition between the diurnal birds of prey and the Owls; but since it has been conclusively shown that the latter have little or nothing in common with the former, and have been removed to the midst of the so-called”Pica-rian”birds, a further examination of the various characters of the Ospreys has been necessary.

According to Pycraft the outer toe is not more reversible than in ordinary Accipitres, and, all things considered, it seems likely that they find their closest relatives among the Honey Buzzards and their allies, being by some authorities, indeed, placed in the subfamily Pernince, but it is perhaps best to regard them as constituting by themselves a distinct subfamily (Pandionince).

Ospreys, or Fish Hawks, as they are more commonly called in this country, enjoy an almost cosmopolitan distribution, being absent only from southern South America, New Zealand, Iceland, and some parts of Australia.

They are so well known that an extended description is perhaps unnecessary, yet a few of the more important characters may be mentioned. When perching, the toes are disposed as in ordinary diurnal birds of prey, but when they capture a fish the toes are opposed in pairs, the outer toe being, as above pointed out, quite reversible. This reversibility permits of a very secure hold on their prey, which is usually an advantage, although, as will be shown later, the very security of the hold works occasionally to their detriment.

The feet are large and powerful, the toes being unconnected and provided with very large, strongly curved claws, which are of equal length, and narrowed and rounded on the under sides. The whole of the rather short tarsus and the toes are covered with rough, somewhat imbricated, projecting scales, and the under surface of the toes is covered with quite prominent pointed spicules, — an adaptive character, found also in other piscivorous Accipitres, as for example the genus Busarellus. The plumage, while close and compact, is without aftershafts, thus agreeing with the Owls. The bill is inflated, the cere depressed, and the nostrils not concealed by bristles.

They have long, pointed wings in which the coverts as well as the primaries are very hard and stiff. In color the Ospreys are dark brown or grayish brown above and mainly pure white below, with slight variations in the various races. The length is from twenty-two to twenty-five inches and the spread of wings about five feet.

Some three or four species of Ospreys have been described, but it is now generally recognized that there is but a single species, which in different parts of its range has assumed sufficient differences in size and plumage to warrant being separated as more or less well marked subspecies. The principal or central form is the European Osprey (Pandion haliaetus haliaetus), which is found throughout the Eastern Hemisphere and has the breast always spotted with brownish.

The next in importance is the American Osprey (P. h. carolinensis), found throughout temperate and tropical America in general, except in the Bahamas, where there is a local race sometimes recognized as the Bahama Osprey (P. h. ridgwayi). The first has the breast usually entirely without spots, while the latter is a smaller form with the back paler than in the American Osprey, and the bill much larger and more swollen. The smallest of all is the Australian Osprey (P. h. kucocephalus) of Australia and the Indo-Malayan islands.

 

 

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