Part 11

Before discoursing upon its nesting habits it is fitting that I should try to describe the night heron, so that the bird may be recognised when next seen. I presume that everyone knows what a heron looks like, but possibly there exist persons who would be at a loss to say wherein it differs from a stork or a crane. It may be readily distinguished from the latter by its well-developed hind toe. Storks and herons are perching waders, while cranes do not trust themselves to trees because they cannot perch, having no hind toe to grasp with. The heron’s bill is flatter and more dagger-shaped than that of a stork. Moreover the former possesses, inside the middle claw, a little comb, which the stork lacks. The heron flies with neck drawn in, head pressed against the back, and beak pointing forwards. It never sails in the air, but progresses, like the flying-fox, with a steady, continuous flapping motion. So much for herons in general. To those who would learn more of these and other long-legged fowls I commend Mr. Frank Finn’s excellent little book, entitled _How to Know the Indian Waders_.

The night heron is considerably smaller than the common heron—the heron we see in England, and larger than the Indian paddy bird—the ubiquitous fowl that looks brown when it is standing and white when it is flying. The head and back of the night heron are black, the remainder of the upper plumage is grey, the lower parts are white. There are two or three long, white, narrow feathers, which grow from the back of the head and hang down like a pigtail. The eye is rich ruby-red. Young night herons are brown with yellowish spots, and the eye is deep yellow.

Any resident of Madras may see this species if he repair to the Redhills Tank. One of the islands in that tank supports a considerable population of night herons and little cormorants. The former nest in the trees on the island in July. The place is well worth visiting then. As the boat carrying a human being approaches the islet, all the night herons fly away without a sound. They love their young, but not so much as they love themselves, so they leave their offspring at the first approach of the human visitor and remain away until he turns his back on their nesting-ground. A night heron never allows his valour to get the better of his discretion. The nest is a platform of twigs placed anywhere in a tree. Four pale greenish-blue eggs are laid. A heronry is a filthy place. The possessors are, like our Indian brethren, utterly regardless of the principles of sanitation. The whole island will be found white with the droppings of the birds, and the unsavoury smell that emanates therefrom would do credit to a village inhabited by _chamars_. Although they are evil-tempered, cantankerous creatures, night herons always nest in company. It is no uncommon thing to find half a dozen nests in the same tree, so that the sitting birds are able to compare notes while engaged in the duties of incubation. Both the parent birds take part in nest construction, and, as they work by day, it is quite easy to watch the process. They wrench small branches from trees, and, as they have only the beak with which to grasp these, they find twig-gathering hard work. When a twig has been secured it is dropped on to the particular part of the tree in which the bird has thought fit to build. Forty or fifty twigs dropped haphazard in a heap constitute the nest. The birds make a great noise while engaged in building. Quarrels are of frequent occurrence. It sometimes happens that two birds want the same twig; this invariably gives rise to noisy altercation. The crows too are provocative of much bad language on the part of the night herons. Whenever any of the crows of the neighbourhood has nothing else to do, he says to a kindred spirit: “Come, let us worry the night herons.” Whereupon the pair—_Arcades ambo_—go and pretend to show the herons how to build a nest.

When, my friends, you consider the untidiness and filthiness of the heron’s nest, you will be able to appreciate to the full the audacity of the latest falsehood circulated by the plume trade—to wit, the egret plucks out its nuptial plumes, which constitute the “osprey” of commerce, and weaves these into the nest to make it more cosy; and, after the young ones are fledged, some honest fellow visits the nest and disentangles the plumes therefrom!

A baby heron is a disgustingly ugly creature. It is a living caricature. Patches of long hair-like feathers are studded, apparently haphazard, over its otherwise naked body and give it an indescribably grotesque appearance. It looks like a bird in its dotage. If you lift a young heron out of the nest you will probably find that his “corporation” is distended to bursting-point, and, if you do not handle him carefully, a half-digested frog will, as likely as not, drop out of him!

The farther north one goes the earlier in the year does the night heron breed. In Kashmir the nesting season is in full swing in March. In the Punjab April and May are the nesting months; in Madras the birds do not begin to build until July; and I have seen eggs at the end of August. It is my belief that the night heron is a migratory bird. During the winter months not a single specimen of that species is to be seen in or about Lahore, but they migrate there regularly every April. They disappear again to I know not where when they have reared up their young.

XXI THE CEMENT OF BIRD MASONS

Birds may be divided into two classes—those which build nests and those which do not. To the latter belong the parasitic starlings and cuckoos, which drop their eggs in the nests of other birds; those, such as plovers, which lay their eggs on the bare ground; and those which deposit them in holes, in the earth, in trees, in banks, or in buildings, as, for example, the Indian roller or blue jay (_Coracias indica_).

Intermediate between the birds that build nests and those which do not—for there are no sudden transitions, no sharply defined lines of division in nature—are those birds which merely furnish, more or less cosily, the ready-made holes in which they deposit their eggs. The common myna (_Acridotheres tristis_) affords a familiar instance of this class of birds. Some of the nest-builders are really excavators; they dig out their nests in a tree or bank. The woodpeckers and the bee-eaters are examples of these. The rest of the nest-builders actually construct their nurseries. These buildings are of various degrees of complexity. Crows, doves, birds of prey, herons, and a few other families are content with a mere platform of sticks and twigs, which rests in the fork of a tree, or on a ledge or other suitable surface. The birds which build primitive nests of this description are not put to the trouble of seeking or manufacturing any cohesive materials. It is only when the nest takes some definite shape and form that means have to be found of binding together the materials of which it is composed, and of attaching the whole to that which supports the nest. In such cases the component materials are either woven or cemented together. It is among the woven nests that we find the highest examples of avian architecture. The homes of the weaver-bird (_Ploceus baya_) and of the Indian wren-warbler (_Prinia inornata_) are constructed with a skill that defies competition. But it is not with these wonderful nests that we are concerned to-day. It must suffice to say that woven nests have to be supported; they cannot float in the air. There are various methods of supporting them. The nest may be firmly wedged into a forked branch. It may be bound to its supports, as in the case of the nest of the king crow (_Dicrurus ater_). The supporting branches may be worked into its structure, as is done by _Prinia inornata_. The nest may hang, as does that of _Ploceus baya_. It may be cemented to its support, as in the case of the nests of the various swifts; or it may rest on supporting fibres which are slung on to a forked branch, just as a prawn net is slung on to its frame. The golden oriole (_Oriolus kundoo_) resorts to this ingenious device.

Coming now to those nurseries in which the building materials are cemented together, we must first consider the nests of the swallows and swifts. These birds secrete a very sticky saliva, which quickly hardens when it is exposed to the air. This constitutes an excellent cement. Watch a swift working at its nest under the eaves of a house. It flies to it with a feather or piece of straw carried far back in the angle of its mouth, hangs itself by means of its four forwardly directed toes on to the half-completed nest, which is stuck on to the wall of the house, and, having carefully placed the feather or straw in the required position, holds it there until the sticky saliva it has poured over it has had time to harden and thus firmly glue the added piece of material to the nest. The bits of straw, feathers, etc., may be said to constitute the bricks, and the saliva the cement of the swift’s nest. Some swifts build their nests exclusively of their saliva. These constitute the “edible birds’ nests” of commerce, and may be likened to houses built entirely of cement. The martin (_Chelidon urbica_), the common swallow (_Hirundo rustica_), and the wire-tailed swallow (_H. smithii_) construct their nests of clay and saliva. They repair to some puddle and there gather moist clay, which they stick on to some building, so as to form a projecting saucer-shaped shelf. In this the eggs are laid. But nature has not vouchsafed sticky saliva to all birds, so that many of them have to find their cement just as they have to seek out the other building materials they use.

The chestnut-bellied nuthatch (_Sitta castaneiventris_), which nestles in holes in trees, fills up all but a small part of the entrance with mud “consolidated with some viscid seed of a parasitical plant.”

The hornbills close up the greater part of the orifice of the hole in which they nest with their droppings mixed with a little earth.

Hume informs us the rufous-fronted wren-warbler (_Franklinia buchanani_) utilises a fungus as its cement. “In all the nests that I have seen,” he writes, “the egg-cavity has been lined with something very soft. In many of the nests the lining is composed of soft, felt-like pieces of some dull salmon-coloured fungus, with which the whole interior is closely plastered.”

The cement which is most commonly used is cobweb. I do not think that I am exaggerating when I say that cobweb enters extensively into the structure of the nests of more than one hundred species of Indian birds. What birds would do without our friend the spider I cannot imagine.

The nest of some birds is literally a house of cobwebs. The beautiful white-browed fan-tail fly-catcher (_Rhipidura albifrontata_) is a case in point. Its nursery is so thickly plastered with cobweb as to sometimes look quite white. It is a tiny cup that rests on a branch of a bush or small tree, and is composed of fine twigs and roots, which are cemented to the supporting branch and to one another by cobweb. This the bird takes from the webs of those trap-door spiders which weave large nets on the ground.

Utterly regardless of the feelings of the possessor of the web, the fly-catcher takes beakful after beakful of it, and smears it over the part of the branch on which the nest will rest. It then sticks to this some dried grass stems or other fine material, next adds more cobweb, and continues in this manner until the neat little cup-shaped nest is completed. This, as I have already said, is thickly coated exteriorly with cobweb to give it additional strength.

The sunbirds or honeysuckers make nearly as extensive use of cobweb in nest construction as do the fan-tailed fly-catchers. Loten’s honeysucker (_Arachnechthra lotenia_) seeks until it finds a large spider’s web stretched horizontally across some bush; it then proceeds to build its nursery in the middle of this. As the material is added the nest grows heavier, and thus depresses the middle of the web until it at last assumes the shape of a V, in the angle of which the mango-shaped nest is situated. The nursery is thus suspended from the bush by the four corners of the cobweb.

A spider’s web looks such a flimsy affair that it does not seem possible that it could support a nest peopled by a number of birds. Sometimes the nest derives additional support by being attached to other branches. Moreover, a tiny creature such as a sunbird is almost as light as the proverbial feather. Then cobweb is exceedingly elastic, and, considering its attenuity, is able to support a surprising amount of weight. It occasionally happens that the common garden spider (_Epeira diadema_) is not able to find a _point d’appui_ to which it can attach the lower part of its web; it then utilises a stone (which may be as much as a quarter-inch in each dimension) as a plummet to make the nest taut. This comparatively heavy stone hangs by a single thread.

I have sometimes amused myself by testing the strength of a strand of cobweb stretched across a path, by hanging bits of match or other light material on it. In one experiment a gossamer thread, thirty feet in length, stretched across a road, bore the weight of five blades of grass which were hung upon it. The sixth blade proved to be the last straw that broke the camel’s back.

The strength of cobweb is proved by the fact that many of the birds that build hanging nests use it as cement to attach them to the supports from which they are suspended. The Indian white-eye (_Zosterops palbebrosa_) fixes its tiny oriole-like nest to the supporting branches, not by fibres, but by cobweb. In the same way the yellow-eyed babbler (_Pyctorhis sinensis_), whose nest is shaped like an inverted cone, attaches this by cobweb to the stems of the crop in which it is situated.

The common honeysucker (_Arachnechthra asiatica_), whose nest looks like a tangle of dried twigs and other rubbish, uses much cobweb in the construction thereof. The little nursery is suspended by means of cobweb from some projecting branch of a bush, and the various materials which compose it are stuck together with spider’s web; but in this case some sticky resinous substance is usually used in addition to the cobweb.

The tailor-bird (_Orthotomous sutorius_) always uses cobweb to draw together the edges of the leaf or leaves that compose its nest. Having made a series of punctures along the edges of the leaf to be utilised, it procures some cobweb, and, having attached it to one edge of the leaf, carries the strand across to the other edge and, before attaching it to this, pulls it so tightly as to draw the two edges together. When the nest has taken its final shape the bird strengthens the first attenuated strands of cobweb by adding more cobweb or some threads of cotton.

Many birds which weave their nests plaster the exterior more or less thickly with cobweb so as to add strength to the structure.

It would be wearisome to detail all the kinds of nest into the composition of which cobweb enters. Sufficient has been said to show that this very useful substance is the favourite cement of bird masons.

XXXII INDIAN FLY-CATCHERS

There exist in the Indian Empire no fewer than fifty-one species of fly-catcher. This fact speaks volumes for the wealth of both the bird and the insect population of India. Fly-catchers are little birds that feed exclusively on insects, which they secure on the wing. Their habit is to take up a strategic position on some perch, usually the bare branch of a tree, whence they make sallies into the air after their quarry. Having secured the object of their sortie—and this they never fail to do—they return to their perch. A fly-catcher will sometimes make over a hundred of these little flights in the course of an hour; the appetite of an insectivorous bird appears to be insatiable. All fly-catchers obtain their food in this manner, but all birds which behave thus are not members of the fly-catcher family. As fly-catchers are characterised by rather weak legs, and, in consequence, do not often descend to the ground, they are of necessity confined to parts of the country well supplied with trees. Thus it comes to pass that the great majority of fly-catchers are found only in well-wooded hill tracts. Four or five species, however, occur commonly in the plains. With two of these—the glorious paradise fly-catchers (_Terpsiphone_) and the very elegant fan-tail fly-catchers (_Rhipidura_)—I have dealt in my former books. I therefore propose to confine myself to some of the many other species. Of these last, the brown fly-catcher (_Alseonax latirostris_) is the one most frequently met with in the plains. This is the most inornate of all the fly-catchers. As its name implies, brown is its prevailing hue. Its lower parts are, indeed, whitish, and there is an inconspicuous ring of white feathers round the eye, but everything else about it is earthy brown. It is the kind of bird the casual observer is likely to pass over, or, if he does happen to observe it, he probably sets it down as one of the scores of warblers that visit India in the cold weather. It is only when the bird makes a sudden dash into the air after an insect that one realises that it is a fly-catcher. The brown fly-catcher is an Ishmaelite. It seems never to remain for long in one place, and, although it may be seen at all times of the year, its nest does not appear ever to have been found in this country.

A more ornamental fly-catcher which occasionally visits the plains is the grey-headed fly-catcher (_Culicapa ceylonensis_). In this species the head, neck, and breast are ash-coloured, the wings and tail are dark brown, the back greenish yellow, and the lower parts dull yellow. This fly-catcher is common both in the Nilgiris and the Himalayas. It has the usual habits of the family. Like the majority of them it is no songster, although it frequently emits a cheeping note. Its nest is a very beautiful structure, a ball of moss which is attached to a moss-covered tree or rock, more often than not near a mountain stream.

Fly-catchers usually nidificate in the neighbourhood of water, because that element favours the existence of their insect food.

_Siphia parva_—the European red-breasted fly-catcher—is a species which visits the plains of India in the cold weather, but not many individuals penetrate so far south as Madras. This bird is easily recognised, since the cock bears a strong likeness to the familiar English robin red-breast. I may here mention that an allied species—the Indian red-breasted fly-catcher, _S. hyperythra_—summers in Kashmir and winters in Ceylon, but, curiously enough, it has not been recorded from the plains of India. It would thus seem to fly from Kashmir to Ceylon in a single night. Even so, it would be very extraordinary if an occasional individual did not fail to perform the whole journey in so short a space of time; therefore, this species should be watched for in South India in spring and autumn. It is easily distinguished from allied species by a black band which surrounds the red breast and abdomen.

As it is impossible to detail in one brief essay all the species of fly-catcher found in the Indian hills, I propose merely to mention those that are most common in the Nilgiris and the Himalayas, and then to make a few observations on fly-catchers in general. In addition to the fan-tail, the grey-headed and the brown fly-catchers, the following species are abundant in the Nilgiris: Tickell’s blue fly-catcher (_Cyornis tickelli_), the Nilgiri blue fly-catcher (_Stoparola albicaudata_), and the black and orange fly-catcher (_Ochromela nigrirufa_). In the Himalayas, the paradise fly-catcher is common in summer at lower altitudes. Above 6000 feet elevation the following are the species most commonly seen: the grey-headed fly-catcher, the white-browed blue fly-catcher (_Cyornis superciliaris_), and the beautiful verditer fly-catcher (_Stoparola melanops_), which is no mean songster.

Fly-catchers form a most interesting group of birds. It is, I maintain, quite impossible for any man possessed of a logical mind to contemplate this family without discovering that the theory of natural selection is utterly inadequate to account for the variety of animal life that exists upon the earth. The habits of practically all the fly-catchers are identical. They all dwell in an arboreal habitat; nevertheless, the various species display great dissimilarity in outward appearance. Some species are brightly plumaged, others are as dully clad as a bird can possibly be. Some have crests and long tails, others lack these ornaments. The adult cock paradise fly-catcher, with his long, white, satin-like tail feathers, is the most striking of birds, while the brown fly-catcher is less conspicuously attired than a hen sparrow. This is not the only difficulty presented to the theory of natural selection by fly-catchers. In some species, as, for example, the paradise fly-catcher, the sexes are altogether dissimilar in appearance, while in others the most practised eye cannot distinguish between the cock and the hen. Nor does there appear to be any connection between nesting habits and the presence or absence of sexual dimorphism. The fan-tail fly-catchers, in which the sexes are alike, and the paradise fly-catchers, in which they differ widely, both build little cup-shaped nests in the lower branches of trees, and in both the cock shares with the hen the duty of incubation. Again, the verditer and the white-browed blue fly-catchers build their nests in holes in trees; yet in the former both sexes are blue, while in the latter the cock only is blue.

Further, in the fly-catchers we see every gradation of sexual dimorphism, from a difference so slight as to be perceptible only when the sexes are seen side by side, to a difference so great as to make it difficult to believe that the sexes belong to one and the same species. It must, therefore, be obvious to any sane person that neither natural nor sexual selection can be directly responsible for the colouration of many species of fly-catcher.

Another interesting characteristic of the fly-catchers is the total absence of green in the plumage of any of them. They are birds of a variety of colours; they display many shades of blue, yellow, orange, red, grey, and brown, also black and white; but not one carries any green feathers. Yet they are essentially arboreal birds, so that green would be a very useful colour to them from the point of view of protection from enemies. From the fact, then, that none of the fly-catchers are green, we seem to be compelled to infer that there is something in their constitution that prevents green variations appearing in their plumage.