There are two Hebrew words thus translated in our version. (See Bochart, Hieroz. 3:20 sq.)
1. שָׁלָך (shalak', that which casts itself down; Sept. καταῤῥάκτης, Vulg. merculus, Syr. and Chald. fish-catcher; occurring only in Le 11:17; De 14:17), in common with the usual Greek version καταράκτης, is considered to have reference to darting, rushing, or stooping like a falcon; and accordingly has been variously applied to the eagle, the jerfalcon, the gannet, the great gull, and the cormorant. The passages where it occurs only inform us that it was an unclean bird, and associate it with the "gull." Its apparent Greek name, cataractes, though noticed by several authors, is not always referred to the same genus, some making it a minor gull, others a diver. Cuvier thinks Gesner right in considering it to denote a gull, and it certainly might be applied with propriety to the black-backed gull, or to the glaucous; but, although birds of such powerful wing and marine habitat are spread over a great part of the world, it does not appear that, if known at the extremity of the Mediterranean, they were sufficiently common to have been clearly indicated by either the Hebrew or Greek names, or to have merited being noticed in the Mosaic prohibition. Both the above are in general northern residents, being rarely seen even so low as the Bay of Biscay, and the species now called "Lestris cataractes" is exclusively Arctic. With regard to the cormorant; birds of that genus are no doubt found on the coasts of Palestine, where high cliffs extend to the sea-shore, such, for example, as the Phalacrocor ix pygmaeus; but all the species dive, and seldom, if ever, rush flying upon their prey, though that habit has been claimed for them by commentators, who have mixed up the natural history of "cormorants" with that of the "sula" or "gannet," which really darts from great elevations into the sea to catch its prey, rising to the surface sometimes nearly half a minute after the plunge. But the gannet (solan goose) rarely comes further south than the British Channel, and does not appear to have been noticed in the Mediterranean. It is true that several other marine birds of the North frequent the Levant, but none of them can entirely claim Aristotle and Oppian's characters of "cataractes;" for, though the wide throat and rather large head of the dwarf cormorant may be adduced, that bird exceeds in stature the required size of a small hawk, and fishes, it may be repeated, swimming and diving, not by darting down on the wing, and is not sufficiently numerous or important to have required the attention of the sacred legislator.
Thus reduced to make a choice where the objections are less and the probabilities stronger, we conclude the shalak to have been a species of "tern," considered to be identical with the Sterna Caspica, so called because it is found about the Caspian Sea; but it is equally common to the Polar, Baltic, and Black Seas, and, if truly the same, is not only abundant for several months in the year on the coast of Palestine, but frequents the lakes and pools far inland, flying across the deserts to the Euphrates, and to the Persian and Red Seas, and proceeding up the Nile. It is the largest of the tern or sea-swallow genus, being about the weight of a pigeon, and near two feet in length, having a large black-naped head, powerful, pointed crimson bill, a white and grey body, with forked tail, and wings greatly exceeding the tips of the tail; the feet are very small, weak, and but slightly webbed, so that it swims perhaps only accidentally, but with sufficient power on land to spring up and to rise from level ground. It flies with immense velocity, darting along the surface of the sea to snap at mollusca or small fishes, or wheeling through the air in pursuit of insects; and in calm weather, after rising to a great height, it drops perpendicularly down to near the surface of the water, but never alights except on land; and it is at all times disposed to utter a kind of laughing scream. This tern nestles in high cliffs, sometimes at a very considerable distance from the sea. (See the Penny Cyclopaedia, s.v. Tern.)
2. קָאִת (kaath'), rendered "cormorant" in our version in Isa 34:11; Zep 2:14, is elsewhere translated "PELICAN," q.v.
The cormorant belongs to the natural order of the Pelicanidae of Linnaeus, and the species have the characteristic habit of watching on high cliffs, and, on perceiving a fish in the water, of darting down like an arrow and seizing its prey. The "greater cormorant," however, more frequently shoots along in a line nearly close to the surface of the water, or, sitting on the wave, dives after the prey. It is trained to fish for man's use in China. It is common on the coasts of Syria and Palestine; Rauwolff saw numbers of them along the sea-washed crags of Acre, which he mistook for sea-eagles.
The cormorant is a widely-diffused genus, and is found in almost every country in the world. (See the Penny Cyclopoedia, s.v. Pelicanidai.) The large kind weighs about seven pounds, and is nearly of the same size as the goose; it lives upon fish, and has a long, straight, and compressed bill; with the upper mandible hooked at the point, to confine the prey with the greater security; its head and neck are of a sooty blackness, more resembling in figure those of the goose than of the gull. Its distinguishing character, however, consists in its toes being united by membranes, and by the middle toe being notched like a saw, to assist it in holding its fishy prey. On the approach of winter these birds are seen dispersed along the seashore, and ascending the mouths of rivers; they are remarkably voracious, and have such a quick digestion that the appetite appears insatiable. They build their nests on the highest parts of the cliffs that overhang the sea; the female usually lays three or four eggs about the size of those of a goose, and of a pale green color. SEE BIRD.