BIRD. 



431 



rejecting the kernels or pips. But whatever may be 

 tiie nature of their food, there is a general character 

 of the bill which runs through the whole tribe ; and, 

 though those which feed more upon pulpy fruits have 

 the bill more enlarged in its cross dimensions than 

 the others, yet the figure of one bill is a very good 

 index to the whole better than in any other tribe of 

 birds at once so numerous and so varied. 



This tribe are more peculiarly characteristic of the 

 tropical forests than any other of the feathered races; 

 because, though they are often found flying over the 

 open places between clump arid clump of the forests, 

 and shifting from place to place as they exhaust the 

 supply of food, they are more in the trees, and, feel- 

 ing the perfection of their climbing powers, are less 

 apt to take wing on being observed, than any race 

 which inhabits the same places. They are constantly 

 in motion, except when they seek their repose, which 

 is usually in the islets of rivers, or other places which 

 are not easily accessible, and they resort there in 

 numbers ; and when they are in motion they are 

 abundantly clamorous. Their natural voices are 

 harsh, but they are easily taught to whistle, to arti- 

 culate, and to imitate very varied sounds. 



It is not owing to the form of the bill or the tongue 

 that parrots or any other birds articulate, because their 

 organ of voice is at the lower or pulmonary end of 

 the windpipe, and not at the larynx or upper end. 

 But their powers of articulation are sometimes really 

 wonderful : the coincidences between the questions 

 put to them and the answers which they return, must 

 in all cases be regarded as purely accidental ; and 

 they claim their appearance of understanding, just as 

 the predictions of pretended seers do their supposed 

 knowledge of the future, from the fact that the ninety 

 nine cases in which there is no coincidence are for- 

 gotten, while the one case out of the hundred in which 

 the answer agrees with the question is remembered 

 and repeated. 



The disposition which these birds have to imitate 

 sounds, not only different from their own hoarse cries 

 in their native forests, but from any which they can 

 hear there, are, however, indications of a very curious 

 instinct, but of one which, as is the case with all 

 instincts, it is vain to hope for an explanation upon 

 the principles of reason. 



The leading uses of the parrot's bill are, breaking 

 hard vegetable substances, and climbing. A pair ot 

 nutcrackers is the nearest comparison to it in artificer 

 instruments, but the bill is beyond all comparison the 

 more universal and effective. This bill does not snap 

 or acquire any force of momentum before it conies 

 in contact with the substance to be acted on. It 

 works wholly by pressure ; but the pressure is accom- 

 panied by a sliding motion, which differs with the 

 decree of exertion. The lower mandible is raised by 

 very powerful muscles, and it is at the same time 

 puslied a little forwards ; the upper mandible has 

 much less motion than the lower, but still it has more 

 than in most birds ; and when the bill is exerted with 

 great force, it has a motion downwards and back- 

 wards at the same time. The substance acted on 's 

 thus wrenched round at the same time that it is pressed 

 by the cutting edges of the mandibles ; and every 

 one who has attended to the subject, knows how very 

 much a cutting operation is strengthened by accom- 

 panying it with a wrenching one. 



The muscles which move the mandibles are very 

 powerful, and give that peculiar fulness which appears 



in all the cheeks of the tribe ; and the motion of the 

 upper mandible, limited as it is in space, brings tne 

 whole of them into action. It is these compound 

 motions of the working parts of animals, which enable 

 them to act with so much less exertion than our 

 mechanical contrivances ; and taking time and effect 

 both into the estimate, there is no tool by means of 

 which the shell of a hard nut could be broken, with- 

 out the expending of far more than double the power 

 which is expended by a parrot. The tongue is of 

 considerable use in guiding the substance to the most 

 effective part of the mandibles ; and even the motions 

 of the neck are of service in breaking detached sub- 

 stances, as well as in detaching fast ones. 



Very hard substances are broken between the 

 point of the under mandible and the hook of the upper 

 one, the lower side of which is slightly hollowed and 

 roughened like a mill-stone by means of angular fur- 

 rows, with their apices directed towards the tip. 



The bills of the falcon, the crossbill, and the parrot, 

 may be reckoned the three most powerful bills in the 

 action of the mandibles that occur in the whole class, 

 and as their action is wholly structural, not deriving 

 any assistance from momentum, they may be reckoned 

 the three most perfect species of mechanism the first, 

 for tearing ; the second, for wrenching open ; and the 

 third, for breaking and bruising ; and all of them are 

 so formed as to have compound motions. 



There are several tolerably distinct forms of bill 

 in this very numerous and abundant family. The 

 parroquets, which fly much from branch to branch in 

 search of their food, have the bill smaller than the 

 others, not exceeding one-third the length of the head, 

 and not very broad ; but it is very firm in its texture, 

 and perhaps proportionably the most powerful of 

 any. The parrots, properly so called, which are the 

 most scandent, have it half the length of the head, 

 and very thick and strong. The cockatoos, which 

 inhabit more marshy places, and live upon softer food 

 than the others, have the bill feebler. The maccaws, 

 which use the wing more than any of the others, and 

 find much of their food on the tops of forest trees, 

 have the bill large, as long as the head, and very 

 sharp. When birds feed wholly or partially on the 

 wing, the bill is generally larger in proportion as the 

 (bod is smaller. The ground parrots, which are better 

 walkers than the rest, have the bill large, but the food 

 appears to be, in part at least, taken by the tongue. 



Cockatoo. 



which is more slender than that of the others, but 

 capable of being protruded, and armed at the tip with 

 a horny portion cleft in two. The above figure will 

 show the general form of the bill. 



