CLIMBING AND SINGING BIRDS— RANGE OF THE SENSES. 



oiled, and their bodies are thus protected from the wet. A bird 

 swimming on the surface of the water maintains its position with- 

 out difficulty. Each stroke with its legs produces a forward move- 

 ment. Generally it uses the feet only for swimming ; it folds them 

 together, and pushes them forward, spreading out the toes and 

 pressing them back. In easy swimming, it uses first one leg and 

 then the other ; in quick swimming, it uses both legs at the same 

 time. In steering, it lays one leg backward, with the toes spread, 

 and uses the other leg as a rudder. 



Diving is often combined with swimming. Some birds swim 

 faster under than upon the surface of the water, and are said often 

 to race with the fishes. Some are only able to dive by darting down 1 

 from a height. The birds that dive from the surface, with a leap or 

 spring, more or less apparent, are called swim or spring divers, and 

 those that dart from a height, pushing divers. The swimming 

 divers are skilled operators ; the pushing divers are bunglers. The 

 former easily dive deep into the water, and remain under the sur- 

 face as long as they can hold their breath ; the latter having forced 

 themselves under the water by a powerful exertion, necessarily 

 soon rise again to the surface. The former search for food under the 

 surface ; the latter only seize such prey as they may have seen from 

 the height. Short wings are suited to swim diving, and long ones 

 to push diving. Only one group of birds — the storm divers — com- 

 bine, in a certain sense, both facilities. The swim divers use both 

 legs and tail ; the push divers principally use the wings, and some 

 other divers use legs, tail, and wings. 



No general rule can be laid down, either as to the rapidity with 

 which birds dive, as to the depths to which they descend, or as to 

 the length of time they remain under water. Eider Ducks are 

 said to dive to the depth of sixty fathoms, and to remain under the 

 surface six minutes. The majority of diving birds do not, however, 

 descend to such a depth, and do not remain under water longer than 

 two or three minutes. Other birds, not belonging to the class of 

 swimmers, not only dive, but run along on the ground under the 

 water. 



. Climbing and Singing Birds. 



Climbers. — Many birds possess a great capacity for climbing. 

 For this purpose they chiefly use their feet, sometimes their bills and 

 tails, and occasionally their wings. Parrots are poor climbers. 

 They lay hold of an upper branch with the bill and pull the body 

 up. But Woodpeckers climb more artistically, using only their 

 feet and tail. Some birds flutter upward ; in every rising move- 

 ment they use their wiijgs, lifting them up and then drawing them 

 in. The Alps Wall-creeper (tichodroma murania) moves in this 

 way ; while the Woodpecker climbs with a sort of hop, without 

 moving its wings. Climbers generally move upward or sideways on 

 the upper side of a limb or branch ; but some move downward or 

 forward on the sides of the branch. 



Singing Birds. — Most birds have loud, full, and clear voices, 

 though with many the voice is a shrill, unpleasant squeal. Mute 

 birds are unknown. For their different sensations and impressions, 

 birds have peculiar sounds or notes, forming a kind of language 

 which they understand, and which may, to some extent/be learned 

 by a careful observer. By these sounds and notes, they call each 

 other; they express their love or hate, their joy or grief; they 

 challenge each other to fight ; they warn against approaching ene- 

 mies, and, in short, make an almost endless variety of communi- 

 cations. Not only do individuals of the same species understand 

 each other, but those better endowed communicate with the less- 

 gifted ones. To the warning cry of one of the larger marsh-birds, 

 listen all the smaller rabble in that locality, and by the alarm-cry 

 of the Robin, all the wood-birds in the forest are warned. The 

 tell-tale Tattler sounds an alarm and warns the Ducks of the ap- 

 proaching gunner. The more cautious seem often to act as guard- 

 ians of the entire community of birds. In the season of courtship 



or love-making, birds converse, talking, singing, and caressing. 

 Parent birds speak and sing tenderly and affectionately to their 

 offspring. Some appear to practice in concert, talking to and an- 

 swering each other. Others seem merely disposed to give expres- 

 sion to tl'eir feelings, not caring whether they are understood or 

 not. To these belong the singing-birds, the pets of the creation. 

 In communicating with each other, both sexes appear to be on equal 

 footing ; but the males only are endowed with the privilege of 

 song. Sometimes, but seldom, the females learn to sing a few 

 notes. 



With all the singers proper, the muscles of the lower larynx are, 

 as a general rule, similarly developed, yet their power of song is 

 very different. Each separate kind has its peculiar keys and a 

 certain volume of sound ; each combines these keys or notes in 

 trills, which are easily distinguished by their greater or less full- 

 ness, volume, and power. Some songs are composed of only a few 

 notes, while others contain octaves. Besides, each singing-bird 

 has numerous variations in its song. The same bird has one song 

 on the mountain and a different one On the plain, though the dif- 

 ference can only be distinguished by close and continued observa- 

 tion. A good singer in a certain district may educate inferior ones 

 to sing well, and a bad singer may spoil a good one. Some birds, 

 not satisfied with their own natural song, mix with it the songs of 

 others, and even striking sounds and noises. These we call Mock- 

 ing-birds. Singing-birds are found in all the zones of the earth,, 

 but are most numerous in the temperate zones. 



Range of the Senses. 



Sight. — The structure of the eye enables a bird to command a 

 wide range of vision. Within this range it observes any object 

 with incredible quickness. Birds of prey easily distinguish small 

 mammals. Insect-eaters perceive resting or flying insects at an as- 

 tonishingly great distance. Their eyes move constantly, as the 

 proper focus must be found for each distance. This may be proved 

 by a simple experiment. If the hand is moved toward the eye of 

 a bird of prey, the pupil expands or contracts in proportion as the 

 hand is brought nearer to or moved further from the eye. This 

 shows why these birds see the smallest objects, when sailing thou- 

 sands of feet above the earth. 



Hearing. — The singing of birds proves their acute hearing. 

 Shy birds become aware of approaching danger chiefly by the sense 

 of hearing ; domesticated birds attend to the feeblest call. Birds 

 that have a sort of external ear, doubtless use their hearing as well 

 as sight ; but, as a general rule, it is probable that the hearing of 

 birds is by no means as acute as that, for instance, of the bat, the 

 cat, or any ruminating mammal. ■ 



Smelling. — Though the sense of smell is but feebly developed 

 in birds, yet a certain amount can not be reasonably denied them. 



Tasting. — The sense of taste in birds is dull compared with that 

 of mammals. Birds prefer certain kinds of food, and reject other 

 kinds ; but this can not be ascribed altogether or chiefly to the dis- 

 criminating nature of their sense of taste, since, with few excep- 

 tions, they swallow their food without any sort of mastication, and 

 many birds seem to use the tongue more for probing for, than for 

 tasting their food. 



Feeling. — Birds, in most cases, evidently use the tongue as an 

 organ of feeling. Woodpeckers, Humming-birds, and many oth- 

 ers probe with the tongue the hiding-places of their prey, and 

 by the same organ separate the digestible from the indigestible 

 portions of their food. The general development of the sense of 

 feeling in birds increases the keenness of their perception, and 

 guards them against sudden changes in the weather and other ex- 

 ternal influences. 



