A Book of Natural History Part 9

The Thrushes, Solitaires, Bluebirds, etc., are all beneficial as insect destroyers, and might be well compared with the Robin, which is described quite fully beyond, only they are even less liable to commit injuries to fruits.

The Robin has certainly been accused often enough of being a first-cla.s.s rascal to warrant the belief that there must be at least some grounds for such accusations being made. In his examination of one hundred and fourteen stomachs of this bird, taken during ten months of the year, Professor Forbes, of Illinois, found the contents to consist of sixty-five per cent insects and thirty-four per cent of fruits and seeds. In the estimates of these food percentages taken by the Robin, as well as by other birds, bulk for bulk is taken, i.e., a quart of caterpillars or other insects is equivalent to a quart of cherries or a quart of berries. Professor Forbes asks this question: "Will the destruction of seventeen quarts of average caterpillars, including at least eight quarts of cut-worms, pay for twenty-four quarts of cherries, blackberries, currents, and grapes?" and then answers it in these words: "To this question I, for my own part, can only reply that I do not believe that the horticulturist can sell his small fruits anywhere in the ordinary markets of the world at so high a price as to the Robin, provided that he uses proper diligence that the little huckster doesn't overreach him in the bargain."

Much more might be said in favor of the Robin had I the time and s.p.a.ce at my command.

After having carefully scanned the foregoing notes concerning the food-habits of our birds we cannot afford to continue indifferent to our treatment of them, nor can we even allow our neighbors to kill them though we ourselves have decided to reform in this respect. We must work for a change of heart in our neighbors also.

THE SCISSOR BEAK

(FROM A JOURNAL OF RESEARCHES, ETC.)

BY CHARLES DARWIN.

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It has short legs, web feet, extremely long--pointed wings, and is about the size of a tern. The beak is flattened laterally, that is, in a plane at right angles to that of a spoonbill or duck. It is as flat and elastic as an ivory paper-cutter, and the lower mandible, differently from every other bird, is an inch and a half longer than the upper. In a lake near Maldonado, from which the water had been nearly drained, and which, in consequence, swarmed with small fry, I saw several of these birds, generally in small flocks, flying rapidly backwards and forwards close to the surface of the lake. They kept their bills wide open, and the lower mandible half buried in the water. Thus skimming the surface, they ploughed it in their course; the water was quite smooth, and it formed a most curious spectacle to behold a flock, each bird leaving its narrow wake on the mirror-like surface. In their flight they frequently twist about with extreme quickness, and dexterously manage with their projecting lower mandible to plough up small fish, which are secured by the upper and shorter half of their scissor-like bills. This fact I repeatedly saw, as, like swallows, they continued to fly backwards and forwards close before me. Occasionally when leaving the surface of the water their flight was wild, irregular and rapid; then they uttered loud harsh cries.

When these birds are fis.h.i.+ng, the advantage of the long primary feathers of their wings, in keeping them dry, is very evident. When thus employed, their forms resemble the symbol by which many artists represent marine birds. Their tails are much used in steering their irregular course.

These birds are common far inland along the course of the Rio Parana; it is said that they remain here during the whole year, and breed in the marshes. During the day they rest in flocks on the gra.s.sy plains, at some distance from the water. Being at anchor, as I have said, in one of the deep creeks between the islands of Parana, as the evening drew to a close, one of these scissor-beaks suddenly appeared. The water was quite still, and many little fish were rising. The bird continued for a long time to skim the surface, flying in its wild and irregular manner up and down the narrow ca.n.a.l, now dark with the growing night and the shadows of the overhanging trees. At Montevideo, I observed that some large flocks during the day remained on the mud-banks at the head of the harbor, in the same manner as on the gra.s.sy plains near the Parana; and every evening they took flight seaward. From these facts I suspect that the Rhynchops generally fishes by night, at which time many of the lower animals come most abundantly to the surface. M. Lesson states that he has seen these birds opening the sh.e.l.ls of the mactrae buried in the sandbanks on the coast of Chile; from their weak bills, with the lower mandible so much projecting, their short legs and long wings, it is very improbable that this can be a general habit.

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THE CONDOR

(FROM A JOURNAL OF RESEARCHES, ETC.)

BY CHARLES DARWIN.

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This day I shot a condor. It measured from tip to tip of the wings eight and a half feet, and from beak to tail, four feet. This bird is known to have a wide geographical range, being found on the west coast of South America, from the Strait of Magellan along the Cordillera as far as eight degrees north of the equator. The steep cliff near the mouth of the Rio Negro is its northern limit on the Patagonian coast; and they have there wandered about four hundred miles from the great central line of their habitation in the Andes. Further south, among the bold precipices at the head of Port Desire, the condor is not uncommon; yet only a few stragglers occasionally visit the seacoast. A line of cliff near the mouth of the Santa Cruz is frequented by these birds, and about eighty miles up the river, where the sides of the valley are formed by steep basaltic precipices, the condor reappears.

From these facts, it seems that the condors require perpendicular cliffs. In Chile, they haunt, during the greater part of the year, the lower country near the sh.o.r.es of the Pacific, and at night several roost together in one tree; but in the early part of summer, they retire to the most inaccessible parts of the inner Cordilleras, there to breed in peace.

With respect to their propagation, I was told by the country people in Chile, that the condor makes no sort of nest, but in the months of November and December lays two large white eggs on a shelf of bare rock. It is said that the young condors cannot fly for an entire year; and long after they are able, they continue to roost by night, and hunt with their parents. The old birds generally live in pairs; but among the inland basaltic cliffs of the Santa Cruz, I found a spot, where scores must usually haunt. On coming suddenly to the brow of the precipice, it was a grand spectacle to see between twenty and thirty of these birds start heavily from their resting-place, and wheel away in majestic circles. From the quant.i.ty of dung on the rocks, they must long have frequented this place for roosting and breeding. Having gorged themselves with carrion on the plains below, they retire to these favorite ledges to digest their food. From these facts, the condor, like the gallinazo, must to a certain degree be considered as a gregarious bird. In this part of the country they live altogether on the guanacos which have died a natural death, or, as more commonly happens, have been killed by the pumas. I believe, from what I saw in Patagonia, they do not on ordinary occasions extend their daily excursions to any great distance from their regular sleeping-places.

The condors may oftentimes be seen at a great height, soaring over a certain spot in the most graceful circles. On some occasions I am sure that they do this only for pleasure, but on others, the Chileno countryman tells you that they are watching a dying animal, or the puma devouring its prey. If the condors glide down, and then suddenly all rise together, the Chileno knows that it is the puma which, watching the carca.s.s, has sprung out to drive away the robbers.

Besides feeding on carrion, the condors frequently attack young goats and lambs; and the shepherd dogs are trained, whenever they pa.s.s over, to run out, and looking upwards to bark violently. The Chilenos destroy and catch numbers. Two methods are used; one is to place a carca.s.s on a level piece of ground within an enclosure of sticks with an opening, and when the condors are gorged, to gallop up on horseback to the entrance, and thus enclose them; for when this bird has not s.p.a.ce to run, it cannot give its body sufficient momentum to rise from the ground. The second method is to mark the trees in which, frequently to the number of five or six together, they roost, and then at night to climb up and noose them. They are such heavy sleepers, as I have myself witnessed, that this is not a difficult task. At Valpariso, I have seen a living condor sold for sixpence, but the common price is eight or ten s.h.i.+llings. One which I saw brought in had been tied with rope, and was much injured; yet, the moment the line was cut by which its bill was secured, although surrounded by people, it began ravenously to tear a piece of carrion. In a garden at the same place, between twenty and thirty were kept alive. They were fed only once a week, but they appeared in pretty good health. The Chileno countrymen a.s.sert that the condor will live, and retain its vigor, between five and six weeks without eating; I cannot answer for the truth of this, but it is a cruel experiment, which very likely has been tried.

When an animal is killed in the country, it is well known that the condors, like other carrion-vultures, soon gain intelligence of it, and congregate in an inexplicable manner. In most cases it must not be overlooked, that the birds have discovered their prey, and have picked the skeleton clean, before the flesh is in the least degree tainted.

Remembering the experiments of M. Audubon, on the little smelling powers of carrion-hawks, I tried in the above-mentioned garden the following experiment: the condors were tied, each by a rope, in a long row at the bottom of a wall; and having folded up a piece of meat in white paper, I walked backwards and forwards, carrying it in my hand at the distance of about three yards from them, but no notice whatever was taken. I then threw it on the ground, within one yard of an old male bird; he looked at it for a moment with attention, but then regarded it no more. With a stick I pushed it closer and closer, until at last he touched it with his beak; the paper was then instantly torn off with fury, and at the same moment, every bird in the long row began struggling and flapping its wings. Under the same circ.u.mstances, it would have been quite impossible to have deceived a dog. The evidence in favor of and against the acute smelling powers of carrion-vultures is singularly balanced. Professor Owen has demonstrated that the olfactory nerves of the turkey-buzzard (_Cathartes aura_) are highly developed; and on the evening when Mr.

Owen's paper was read at the Zoological Society, it was mentioned by a gentleman that he had seen the carrion-hawks in the West Indies on two occasions collect on the roof of a house, when a corpse had become offensive from not having been buried: in this case, the intelligence could hardly have been acquired by sight. On the other hand, besides the experiments of Audubon and that one by myself, Mr. Bachman has tried in the United States many varied plans, showing that neither the turkey-buzzard (the species dissected by Professor Owen) nor the gallinazo find their food by smell. He covered portions of highly offensive offal with a thin canvas cloth, and strewed pieces of meat on it; these the carrion-vultures ate up, and then remained quietly standing, with their beaks within the eighth of an inch of the putrid ma.s.s, without discovering it. A small rent was made in the canvas, and the offal was immediately discovered; the canvas was replaced by a fresh piece, and meat again put on it, and was again devoured by the vultures without their discovering the hidden ma.s.s on which they were trampling. These facts are attested by the signatures of six gentlemen, besides that of Mr. Bachman.

Often when lying down to rest on the open plains, on looking upwards, I have seen carrion-hawks sailing through the air at a great height.

When the country is level I do not believe a s.p.a.ce of the heavens, of more than fifteen degrees above the horizon, is commonly viewed with any attention by a person either walking or on horseback. If such be the case, and the vulture is on the wing at a height of between three or four thousand feet, before it could come within the range of vision, its distance in a straight line from the beholder's eye, would be rather more than two British miles. Might it not thus readily be overlooked? When an animal is killed by the sportsman in a lonely valley, may he not all the while be watched from above by the sharp-sighted bird? And will not the manner of its descent proclaim throughout the district to the whole family of carrion feeders, that their prey is at hand?

When the condors are wheeling in a flock round and round any spot, their flight is beautiful. Except when rising from the ground, I do not recollect ever having seen one of these birds flap its wings. Near Lima, I watched several for nearly half an hour, without once taking off my eyes; they moved in large curves, sweeping in circles, descending and ascending without giving a single flap. As they glided close over my head, I intently watched from an oblique position, the outlines of the separate and great terminal feathers of each wing; and these separate feathers, if there had been the least vibratory movement, would have appeared as if blended together; for they were seen distinct against the blue sky. The head and neck were moved frequently, and apparently with force; and the extended wings seemed to form the fulcrum on which the movements of the neck, body, and tail acted. If the bird wished to descend, the wings were for a moment collapsed; and when again expanded with an altered inclination, the momentum gained by the rapid descent seemed to urge the bird upwards with the even and steady movement of a paper kite. In the case of any bird _soaring_, its motion must be sufficiently rapid, so that the action of the inclined surface of its body on the atmosphere may counterbalance its gravity. The force to keep up the momentum of a body moving in a horizontal plane in the air (in which there is so little friction) cannot be great, and this force is all that is wanted. The movement of the neck and body of the condor, we must suppose, is sufficient for this. However this may be, it is truly wonderful and beautiful to see so great a horde, hour after hour, without any apparent exertion, wheeling and gliding over mountain and river.

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THE UMBRELLA BIRD

(FROM TRAVELS ON THE AMAZON.)

BY SIR A. R. WALLACE.

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This singular bird is about the size of a raven, and is of a similar color, but its feathers have a more scaly appearance, from being margined with a different shade of glossy blue. It is also allied to the crows in its structure, being very similar to them in its feet and bill. On its head it bears a crest, different from that of any other bird. It is formed of feathers more than two inches long, very thickly set, and with hairy plumes curving over at the end. These can be laid back so as to be hardly visible, or can be erected and spread out on every side, forming a hemi-spherical, or rather a hemi-ellipsoidal dome, completely covering the head, and even reaching beyond the point of the beak: the individual feathers then stand out something like the down-bearing seeds of the dandelion. Besides this, there is another ornamental appendage on the breast, formed by a fleshy tubercle, as thick as a quill and an inch and a half long, which hangs down from the neck, and is thickly covered with glossy feathers, forming a large pendant plume or ta.s.sel. This also the bird can either press to its breast, so as to be scarcely visible, or can swell out, so as almost to conceal the forepart of its body. In the female the crest and the neck-plume are less developed, and she is altogether a smaller and much less handsome bird. It inhabits the flooded islands of the Rio Negro and the Solimoes, never appearing on the mainland. It feeds on fruits, and utters a loud, hoa.r.s.e cry, like some deep musical instrument; whence its Indian name, _Uera-mimbe_, "trumpet-bird." The whole of the neck, where the plume of feathers springs from, is covered internally with a thick coat of hard, muscular fat, very difficult to be cleaned away,--which in preparing the skins, must be done, as it would putrefy, and cause the feathers to drop off. The birds are tolerably abundant, but are shy, and perch on the highest trees, and, being very muscular, will not fall unless severely wounded.

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HUMMING BIRDS

(FROM THE NATURALIST IN NICARAGUA.)

BY THOMAS G. BELT, F.G.S.

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Soon after crossing the muddy Artigua below Pavon, a beautifully clear and sparkling brook is reached, coming down to join its pure waters with the soiled river below. In the evening this was a favorite resort of many birds that came to drink at the pellucid stream, or catch insects playing above the water. Amongst the last was the beautiful blue, green and white humming-bird; the head and neck deep metallic-blue, bordered on the back by a pure white collar over the shoulders, followed by deep metallic-green; on the underside the blue neck is succeeded by green, the green from the centre of the breast to the end of the tail by pure white; the tail can be expanded to a half circle, and each feather widening towards the end makes the semicircle complete around the edge. When catching the ephemeridae that play above the water, the tail is not expanded: it is reserved for times of courts.h.i.+p. I have seen the female sitting quietly on a branch, and two males displaying their charms in front of her. One would shoot up like a rocket, than suddenly expanding the snow-white tail like an inverted parachute, slowly descend in front of her, turning round gradually to show off both back and front. The effect was heightened by the wings being invisible from a distance of a few yards, both from their great velocity of movement and from not having the metallic l.u.s.tre of the rest of the body. The expanded white tail covered more s.p.a.ce than all the rest of the bird, and was evidently the grand feature in the performance. Whilst one was descending, the other would shoot up and come slowly down expanded. The entertainment would end in a fight between the two performers; but whether the most beautiful or the most pugnacious was the accepted suitor, I know not. Another fine humming-bird seen about this brook was the long-billed, fire-throated _Heliomaster pallidiceps_, Gould, generally seen probing long, narrow-throated red flowers, forming, with their attractive nectar, complete traps for the small insects on which the humming-birds feed, the bird returning the favor by carrying the pollen of one flower to another. A third species, also seen at this brook, _Petasophora delphinae_, Less., is of a dull brown color, with brilliant ear-feathers and metallic-green throat. Both it and the _Florisuga mellivora_ are short billed, generally catching flying insects, and do not frequent flowers so much as other humming-birds. I have seen the _Petasophora_ fly into the centre of a dancing column of midges and rapidly darting first at one end then at another secure half a dozen of the tiny flies before the column was broken up; then retire to a branch and wait until it was re-formed, when it made another sudden descent on them.... I have no doubt many humming-birds suck the honey from flowers, as I have seen it exude from their bills when shot; but others do not frequent them; and the princ.i.p.al food of all is small insects. I have examined scores of them, and never without finding insects in their crops. Their generally long bills have been spoken of by some naturalists as tubes into which they suck the honey by a piston-like movement of the tongue; but suction in the usual way would be just as effective; and I am satisfied that this is not the primary use of the tongue, nor of the mechanism which enables it to be exerted to a great length beyond the end of the bill. The tongue, for one-half of its length, is semi-h.o.r.n.y and cleft in two, the two halves are laid flat against each other when at rest, but can be separated at the will of the bird and form a delicate pliable pair of forceps, most admirably adapted for picking out minute insects from amongst the stamens of the flowers.

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THE FOUNDATIONS OF A WONDERFUL CITY

(FROM THE LIFE OF THE BEES.)

BY MAURICE MAETERLINCK.