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.

In conclusion, note must be made of the fact that fly-catchers, although they subsist almost entirely upon insect diet, appear but rarely to devour butterflies. I have watched fly-catchers closely for several years, and have on two occasions only seen them chase butterflies or moths. Five years ago in Madras I observed a paradise fly-catcher chasing a small butterfly, and recently, in the Himalayas, I saw a grey-headed fly-catcher drop down from a tree and seize a moth that was resting in the gutter. The reason why fly-catchers do not often attack butterflies is obvious; these insects offer very little meat and a great deal of indigestible wing surface. Nevertheless, the theory of protective mimicry is almost exclusively illustrated by examples taken from butterflies. In theory, these creatures are so relentlessly persecuted by insectivorous birds that in order to escape their foes many edible butterflies mimic the appearance of unpalatable species. Unfortunately for theory, few creatures in practice seem to attack butterflies when on the wing, which is just the time when the “mimicry” is most obvious.

The elegant little fly-catchers, then, are birds which mock Darwin, laugh at Wallace, and make merry at the expense of Muller and Bates!