182 



AQUAMARINE AQUIL A. 



Siberia, and we may add in alluvial soils, in the upper 

 parts of Aberdeenshirc. A variety of the beryl is 

 sometimes called by the same name. 



AQUARIUS (Schellenberg). A name proposed 

 for some of the water-bugs. See HYDROMETUJD.E, 

 arid synonymous with the genus Hydrometra of 

 Fabricms.] 



AQUIL A Eagle. A genus of accipitrous or 

 rapacious birds, belonging to the division of diurnal 

 feeders, and to the natural family of the Falconida. 

 In their general characters they may be described as 

 intermediate between the falcons properly so called 

 and the vultures ; and, in their specific characters, 

 some of them approach more nearly to, the first of 

 these groups, and others to the second. 



Their general characters are : the beak very strong, 

 nearly straight in the basal part, but much hooked 

 toward the tip, without any trenchant tooth and 

 corresponding notch as in the falcons, but with a 

 flexure or deviation from the straight line, near the 

 middle of the tomia. The nearer the species ap- 

 proximate to the falcons in their habits, this deviation 

 from the straight line is the more conspicuous, and 

 the curvature of the beak begins the nearer to the 

 base ; and on the other hand, the nearer that their 

 manners approximate to those of the vultures, the 

 tomia and also the greater length of the beak are 

 straight. The tarsi are in general short and very 

 robust, the tendons which they contain being among 

 the most firm and rigid of animal substances. The 

 toes are three before and one in the rear, firm and 

 elastic, and armed with large and powerful crooked 

 claws or talons. Those talons are very sharp at the 

 joints ; and they are partially retractile, or rather 

 they rise by the action of elastic ligaments as soon 

 as the feet of the birds come in contact with a pin- 

 nacle of rock, or other perch ; so that the whole base 

 on which the bird rests is the padded parts of the 

 toes, and the talons are reserved for their proper 

 purpose in the economy of the bird that of clutch- 

 ing and killing prey. The claws on the hind toe 

 and exterior one in front are usually the largest. In 

 all the species the toes are perfectly free in their 

 lateral motions, so that they can clutch at four nearly 

 equidistant points. In those which feed exclusively 

 upon" land animals, the toes have no other motion 

 than this, and that of clutching together with great 

 power ; and they are, strictly speaking, tearing claws, 

 round on their convex sides, but grooved with two 

 sharp edges on their concave ones, so that while they 

 clutch they tear and lacerate with those edges. In 

 the species which subsist chiefly by fishing, the outer 

 toe is reversible, so that the claws grasp two against 

 two ; and in these the claws are not grooved, as that 

 would only tend to cut through the hold which the 

 bird gets of the fish that it clutches in the water. 

 The wings of eagles are very powerful both in their 

 form and the strength of their feathers ; but .they are 

 broad arid rounded, and not adapted for so rapid a de- 

 gree of motion, or such graceful wheeling in the air, as 

 those of the falcons. They are, however, much stronger, 

 and probably the strongest in the whole class of birds. 

 The first quill is very short, and the fourth the longest 

 in the wing ; but so many of them are nearly of the 

 same length that the wings have a blunt or truncated 

 appearance. The tails of eagles are large and power- 

 ful, and capable of much motion, more especially 

 great extension and breadth. All the feathers on 

 the upper part of eagles, more especially those that 

 approach nearest to the falcons, have a firm and 



almost metallic appearance ; but those which approach 

 the vultures have them rather softer; and in those 

 which fish habitually, the under part of the body and 

 the undersides of the wings are feathered something 

 like those of aquatic birds. In the bolder species 

 the feathers of the neck are long and pointed, and 

 they are erectible when the birds are in a state of 

 great excitement. 



The eyes of eagles are proverbially keen and 

 penetrating ; and the sight is the chief and indeed 

 the only sense upon which they depend in the finding 

 of their food. Among the many fabulous stories told 

 of eagles, of which there are more both in number 

 and extravagance, than respecting perhaps any other 

 genus of birds, it is reported that the eagle can fly 

 sunward with the open eyes directed full upon that 

 luminary, without any injury to her powers of vision. 

 But the very structure of the bird prevents the pos- 

 sibility of its looking at the sun, or even looking 

 upward to any considerable angle. The eyes are 

 placed laterally, and they are shielded by projecting 

 upper orbits and orbital feathers for the very purpose 

 of defending them* from the light from above, and 

 rendering them more keen to that from below. 



Eagles have indeed no occasion to look upwards, 

 when they are in the air, or generally when they are 

 in their dwelling places among the cliffs ; for in both 

 situations they themselves are, generally speaking, 

 above all other living creatures ; and though there 

 may be some birds which, in peculiar situations and 

 states of the weather, occasionally soar above the 

 eagles' flight, yet those birds are, at these times at least, 

 not eagles' prey. The power of eagles in seizing their 

 food is in their descent ; and they seldom if ever give 

 chace on the wing, but descend or " stoop " upon 

 their prey when it is on the ground. In that case 

 their weight and their muscular energy together con- 

 spire to give them effect, and that effect is equally 

 grand, and to the animals on which they prey, irre- 

 sistible. But if they were to try hawking on the 

 wing after flying game, they would fare but scantily ; 

 for their broad wings and tail make them turn so 

 slowly and with so much difficulty that there are 

 very few birds which would not throw them out so 

 repeatedly, as to exhaust even their great strength in 

 a fruitless chace. 



The vision of eagles is no doubt wonderfully acute, 

 as appears from the height at which they are found 

 beating their pastures for even comparatively small 

 game, and game which differs not much in colour 

 from the vegetable covering of the ground. In these 

 cases it is probable that their vision commands the 

 whole of a circular horizon two or three miles in 

 diameter, and that they can in a moment scan every 

 point within that wide range. The surface immedi- 

 ately under them appears to be that which they 

 command the least perfectly ; and a perfect command 

 of that would be of comparatively little advantage to 

 them, inasmuch as an eagle cannot drop perpendicu- 

 larly on its prey, but always in an oblique curve, by 

 means of which it both delivers its whole impetus 

 upon the prey, and prevents unpleasant collision with 

 the ground. 



Mammalia rather than birds seem to be the favour- 

 ite prey of the more powerful eagles, either the 

 smaller ones, such as hares or marmots in their full 

 grown state, or the young of mountain goats, moun- 

 tain antelopes, and other larger species. The eagles 

 which inhabit the mountain ridges w here these abound 

 have, however, generally a spice of the vulture in 



