Birds of the Plains

by Douglas Dewar

The second point upon which I desire to lay stress is the active part taken by the cock paradise flycatcher in incubation. This, again, is, I believe, nothing very uncommon, even in sexually dimorphic species, for I have myself put a cock minivet (Pericrocotus peregrinus) off the nest. Yet this fact seems to dispose of Wallace’s theory that the more sombre hues of the hen are due to her greater need of protection, since she alone is supposed to incubate.

As a matter of fact, a bird sitting on a nest is not, in my opinion, exposed to any special danger, for it seems that birds of prey as a rule only attack flying objects.

Finally, there is the extraordinary metamorphosis undergone by the cock in his fourth year. It is difficult to see how this can have been caused by the preference of the hen for white cock birds, since a great many chestnut ones are observed to breed; the dimorphism must, therefore, have originated late in the life history of the species, and although a hen bird might prefer a white to a chestnut husband, it is difficult to believe that she would prefer a skewbald one, and this skewbald state must have been an ancestral stage if we believe that the transition is due to feminine selection of white birds. I may be asked, “If you decline to believe that the hen has greater need of protection than the cock, how do you account for the phenomena of sexual dimorphism, and if it is not sexual selection which has caused the white plumage of the cock paradise flycatcher to arise, what is it?”

This article has already attained such a length that even had I complete explanations to offer I could not set them forth in this place. I must content myself with giving what I believe to be the key to the solution of the problem. I think that there is little doubt that what a bird looks for in its mate is, not beauty or brilliance of plumage, but vigour and strength. If beauty is a correlative character to strength, then the hen selects the most beautiful of the cocks willing to mate with her, not because of his beauty, but on account of his strength; likewise the cock. Now there is a very intimate connection between the generative cells and the body cells, and the male element tends to dissipate energy and the female element to conserve it. Thus it is that the general tendency of the cock is to become gaily coloured and to grow plumes and other ornaments, while the tendency of the hen is to remain of comparatively sombre hue.

BUTCHER BIRDS

Butcher birds are so called because they are reputed to have a habit of impaling on thorns their larger victims, or as much of them as they, owing to want of accommodation, are incapable of eating at the time of the murder. A bush which displays a number of impaled victims—young birds, lizards, locusts, and the like—is supposed, by a stretch of the ornithological imagination, to look like a butcher’s shop. All that is wanted to perfect the illusion is a sign-board, bearing the legend “Lanius vittatus, Purveyor of Meat.” I must here admit, with characteristic honesty, that I have never set eyes upon such a butcher’s shop, or larder, as it should be called, for the shrike does not sell his wares—he merely stores them for personal consumption. Nor have I even seen a shrike impale a victim. My failure cannot, I think, be attributed to lack of observation; for I never espy one of these miniature birds of prey without watching it attentively, in the hope that it will oblige me by acting as all books on ornithology tell me shrikes do. Every butcher bird I have witnessed engaged in shikar has pounced down upon its insect quarry from a suitable perch, seized the luckless victim upon the ground, immediately carried it back to its perch and devoured it then and there. I have seen this operation repeated scores of times. I, therefore, think I am justified in suggesting that the habit of keeping a larder is probably restricted to the larger species of shrike, and that these only impale their victim when there is still something of it left over, after they have eaten so much that for the time being they cannot possibly stow away any more. Jerdon, I notice, makes no mention of ever having seen a butcher bird behave in the orthodox manner. Colonel Cunningham, who is a very close observer of bird life, says, as the result of a long sojourn in India, that shrikes “do not seem very often to impale their victims, probably because these are usually easily broken up; but when they have secured a lizard they sometimes fix it down upon a stout thorn so as to have a point of resistance whilst working at the hard, tough skin.” If any who read these lines have seen a shrike’s larder, either in India or in England, I should esteem it a great favour if they would furnish me with some account of it.

Let me not be mistaken. I do not say that butcher birds never keep larders, for they undoubtedly do; of this I am satisfied. Thus Mr. E. H. Aitken says of the shrike: “It sits upright on the top of a bush or low tree, commanding a good expanse of open, grassy land, and watches for anything which it may be able to surprise and murder—a large grasshopper, a small lizard, or a creeping field mouse. Sometimes it sees a possible chance in a flock of small birds absorbed in searching for grass seeds. Then it slips from its watch-tower and, gliding softly down, pops into the midst of them without warning, and forgetting all about the true nature of its deep plantar tendons, strikes its talons into the nearest. No other bird I know of makes its attack in this way except the birds of prey. The little bird shrieks and struggles, but the cruel shrike holds fast and hammers at the victim’s head with its strong beak until it is dead, then flies away with it to some thorn bush which is its larder. There it hangs it up on a thorn and leaves it to get tender. . . . This is no fable, I have seen the bird do it.” Again, the Rev. C. D. Cullen, with whom I have enjoyed many an ornithological ramble in England and on the continent of Europe, informs me that once in Surrey he came upon a shrike’s larder, and on that occasion the “shop” consisted of the legs of a young green finch.

The usual food, then, of the butcher bird appears to be small insects. When a suitable opportunity offers, the larger species will attack a lizard or a young or sickly bird, especially a bird in a cage. Of the rufous-backed shrike Mr. Benjamin Aitken writes: “It will come down at once to a cage of small birds exposed at a window, and I once had an amadavat killed and partly eaten through the wires by one of these shrikes, which I saw in the act with my own eyes. The next day I caught the shrike in a large basket which I set over the cage of amadavats.” But, of course, it is one thing to catch a bird in a cage and another to capture it in the open. Shrikes are savage enough for any murder, but most little birds are too sharp for them.

Fifteen species of shrike occur in India. The commonest are, perhaps, the Indian grey shrike (Lanius lahtora) and the bay-backed shrike (Lanius vittatus). The latter is the one that frequents our gardens. He is not a large bird, being about the size of a bulbul. The head and back of the neck are a pretty grey. The back is chestnut-maroon, shading off to whitish near the tail. There is a broad black streak running across the forehead and through the eye, giving the bird a grim, sinister aspect. The breast and lower parts are white; the wings and tail black, or rather appear black when the bird is at rest. During flight the pinions display a conspicuous white bar, and the white outer tail feathers also come into view. The stout beak is black, and the upper mandible projects downwards over the lower one. This further adds to the ferocity of the bird’s mien. It is impossible to mistake a butcher bird; look out for its grey head, broad, black eyebrow, and white breast.

The usual note of the shrike is a harsh cry, but during the breeding season, that is to say, from March to July, the cock is able to produce quite a musical song.