1925

AUSTRALIA'S MOCKING BIRDS

AWAY in the untamed north-west of Australia a pastoralist was having a difficult day through shortage of water, when his troubles were increased by his aboriginal assistant smashing a dusky toe with a sledge-hammer. Soon afterwards extraordinary noises came from a thicket where the native was nursing his injured toe, whereupon the irritated owner shouted, 'If you can't work, you need not make those idiotic noises.' An indignant grunt came from the black boy. 'That nothing mine,' he said, 'that bird!'

This was the English stockman's introduction to the yellowspotted bower bird (Chlamydera guttata), one of Western Australia's representatives of a very remarkable family of birds. The study of voice mimicry in birds involves the birds of the world, of course, but in Australia it is insistent, for the reason that we seem to possess more mockers than does any other country, and because we have at least two mimics, widely differing otherwise, that are superior to mocking birds in any other part of the world.

Why do birds use vocal mimicry? Does it serve any useful purpose? Has food or habitat anything to do with the practice ? Is it confined to particular orders or groups ? Is it common throughout a genus in which one species has been known to mock ? Is mimicry taught by the parent birds ?

Before examining them let us glance at Australia's mocking birds and their abilities. There will be little disagreement when I suggest that our two species and two sub-species of lyre birds (Menura) are the champions of all mockers. That 'wildest of singers,' the American mocking bird (Mimus), has a wider reputation, perhaps, but Americans who have heard our Menura willingly give him the palm. The lyre bird's repertoire, if set down, would look imposing, ranging as it does from the puffing of the engine in a motor omnibus to the squealing of young foxes. It does not, in a state of nature, include the human voice, but only because this is seldom clearly heard by the shy bird.

In semi-confinement, however, the lyre bird has proved to be capable of actually voicing words. A notable case was that of 'Jack,' of Drouin, Victoria, a lyre bird that was caught as a youngster in 1885 and lived about the farm of Mr. S. McNeilly for twenty years. It is on record that Jack's plumage gradually improved, and after six years he developed a magnificent tail. Sometimes he wandered from the farm, but always he returned. While work was going on he was frequently in the way, hence his chief saying, 'Look out, Jack!' Among his favourite imitations were the noise of a horse and dray moving slowly, with the play of the wheels in the axle-boxes, chains rattling, etc.; an occasional 'Gee up, Bess'; and the sounds of a violin, piano, cornet, cross-cut saw, etc. All the more frequent noises about the farm the bird learnt to perfection, such as a pig being killed, a dog howling, a child crying, flocks of parrots screaming, kookaburras laughing, and many cries of small birds. At the sight of strangers the wonderful bird became quiet, but he would follow them like a dog; once he was found three miles away. His usual answer to the men saying, 'Poor Jack!' was 'Not poor Jack! fat Jack!' which the men had taught him.

The long-lived 'Jack' was a Queen Victoria's lyre bird (M. Victoria). He ranks as perhaps our most eloquent illustration of the wonderful vocal ability of these noble creatures. But there are, scattered throughout natural history publications and deserving revival, many other superlative tributes to the mimicry of Menura, including references to the reproduction of other sounds besides bird voices. A Victorian observer tells of a lyre bird excelling himself on a rainy day, for, in addition to bird-calls, he imitated the bark of a cattle-dog, repeated twenty or thirty times, and also the whistle of a man calling the dog off!

Another bush naturalist of standing paid homage to Queen Victoria's lyre bird twenty years ago. 'No sound is too difficult for it to reproduce,' he said, 'and in the case of sweetly musical notes it is an exact reproduction of the originals, while of those of a harsh nature it is a highly refined imitation. The swish of the coach-driver's whip and the sound of the saw and axe are perfect deceptions, and the gliding of one bird's notes into those of another and the rendering of two or more simultaneously are nothing short of marvellous. The male bird is much the better and more powerful whistler, but the female is practically as good a mimic.'

Definite evidence on the latter point-the vocal ability of the female Menura-is given by Mr. T. H. Tregellas, a keen student. As he disturbed a young one at a nest the mother-bird approached, and he says:

Looking straight into our faces, she carolled like a magpie, laughed like a kookaburra, barked like a fox-terrier, yelped like a fox, cackled like a hen, 'tuwhooed' like a young podargus, whistled like a pilot bird, shrieked like a bell-magpie, and wailed like a chough. We were enraptured, enthralled, and there she stood till tears came into our eyes for very joy. She was majestic, sublime, and proved that it is not only the male that mocks.

Most observers have the impression that the lyre bird finds the extraordinary 'laughter' of the kookaburra ('jackass ') difficult to render. I suspect this to depend upon the opportunities afforded the mocker of gripping the queer jumble, which quite probably entails more learning than do simpler and sweeter calls. In New South Wales I have heard the superb lyre bird (M. Νουα Hollandia) give quite a good imitation of a kookaburra duet. Yet I have not heard the same species mimic the cat bird, which is nurnerous in the coastal jungles; nor has Prince Albert's lyre bird (M. Alberti), a northern dweller, been recorded as giving more than a weak imitation of the strange cry that is between the 'yowl' of a cat and the wail of a human infant. Is it that harsh calls make only minor appeal to the Melba-throated lyre bird ? Far be it from me, anyway, to suggest that laughing and crying are not well within the range of this master-mocker of the jungle, bird of the 'glorious tumult of embattled song.'

Here arises a reminder of the relation of the lyre bird to the human poets of its country.

Let me hear the lyre bird's luscious notes
Thieving the ballads from his neighbours' throats,

cries one; and another, capturing something of the bird's own darkling, sweetly pungent atmosphere in the fern gullies, sings of

All the world's sweetness, caught into one voice;
All the world's sorrow, blent into one tone;
Full life, exulting: life that bids rejoice
And makes the earth her throne.

I mentioned that we have two world-beating mimics. The second is the spotted bower bird. Dwellers in the sub-interior of Australia are familiar with the amazing skill of this mocker. What seems to be its own note is a harsh, guttural sound, like that produced by members of the family generally. But this is less remarked on than 'foreign' calls. An observer in the northwest of New South Wales writes of a bower bird that precisely mimicked the sound created by sheep scrambling through a wire fence. He heard, too, these strange birds mimic the cries or calls of eagles, hawks, butcher birds, magpies, and, notably, the wail of a domestic cat. 'Nearly all the birds there gave the cat-call very cleverly.'

This cat-call demands attention. It is general with the spotted bower birds-too general, one suspects, to be a genuine imitation.

The resemblance to the howl of an excited cat is most extraordinary, and certainly the first impulse of a listener is to accept the general belief of inlanders that the bird is giving pure mockery. But after hearing the identical cry in remote places, and hearing of it from other places where even domestic cats gone wild are scarcely likely to be heard, I have reconstructed an opinion in favour of a natural or 'fixed' call,1 just as a somewhat similar cry certainly is with the bower birds' relatives the cat birds.

Indirect support for this suggestion lies in the fact that certain other birds, widely differentiated, occasionally use a cat-like call. Indeed, I have been surprised at the results on this point yielded by a search among fugitive notes of casual observers in many parts of Australia. Thus it is recorded that the large-tailed grass wren of West Australia 'utters a sound precisely like the miew of a cat'; that a white-breasted robin of West Australia ' uttered a series of most cat-like calls'; that the yellow-breasted shriketit has been heard, in New South Wales, to utter ' one curious note, something between the miewing and spitting of a cat'; that a yellow-throated miner, in West Queensland, uttered 'a peculiar cat-like sound'; and that even the familiar singing honey-eater sometimes 'cries like a cat.'

Parenthetically, it has to be noted that none of the birds cited above is recognised as a mimic; therefore the assumption is that the cat-like notes are natural, and only rarely allowed out of the music-box. Really, though, a wail of this kind is essentially a primitive sound, and accomplished sub-consciously, as it were, so that it may be that the cat-like call among birds goes far back in avine history.

Returning to the bower birds, the cat-call crops up again in the case of the bird first mentioned here, the yellow-spotted species in West Australia. Mr. F. L. Whitlock, a collector with much experience, formed the impression that both male and female of this striking species are mimics. He noted, too, that they seem to have a preference for harsh sounds an interesting point which I have shown does not obtain in the case of the lyre bird, nor, indeed, of jungle birds in general. Whitlock heard the yellow-spotted bower bird mimicking the tremulous cries of young hawks and the notes of two species of butcher birds. Certain other sounds, he says, were a perfect imitation of the noises

produced by rabbits running over a heap of dry twigs-an unmistakably new acquirement, as the acacia thicket frequented by the birds accommodated a rabbit warren, the occupants of which could not have been in that secluded area very long. Other sounds, again,' were like the miewing of a cat, and may have been acquired from the red-breasted babbler which was breeding near at hand.' It is necessary to add that if the cat-call of the western bower bird is as realistic as that of the spotted bower bird, it is certainly not an imitation of any other bird-call.

It is clear, however, that this bower-builder and vocalist of the wide spaces of West Australia is almost, if not quite, as clever a mimic as its better known relative, C. maculata. So, too, in the case of the most familiar member of the family, the satin bower bird (Ptilonorhynchus violaceus), which is a brilliant mocker, but not nearly so consistent in the practice as its inland relatives. There are several isolated records of the handsome satin bird mimicking other birds common to its habitat, the most eloquent of these being a note contributed to a newspaper by the late Charles McLennan, a National Park ranger, Victoria:

At times [he wrote] the bird seemed to pour harmony from its very soul. It was a miniature lyre bird, and imitated in a marked degree the calls of the kookaburra (only the first two bars), the butcher bird (which was perfect), and the grating cries of the white cockatoo ; but the screeching of the black cockatoo was its masterpiece. The imitation of the crow shrike and the magpie could hardly be better done, and the peculiar grunt of the native bear was true to nature.

We know less of the vocal powers of the other five Australian bower birds, but it seems certain that one of them, the regent bird, does not exercise mimicry at all. But is not this beauty bird a degenerate bower bird both in voice (very rarely heard) and in its relatively poor (and rarely found) play-house?

A further puzzle is provided by the tooth-billed cat bird. Long regarded as a bower bird, this curious inhabitant of the tropic jungle is certainly allied to the bower birds in its fondness for mimicry and play; but its distinctive eggs are akin to those of the cat birds (whose notes are practically limited to a wail), and its playground is not a bower, but merely a cleared space decorated with leaves a practice that has been reported to be followed by the cat birds proper (Ailuroedus), but which is certainly not now general with these birds. So the supposition arises that cat birds are primitive or degenerate bower birds; they have lost or are losing, or have not thoroughly acquired, the play habit, and they use a clumsy cat-like cry (shown to be a frequent expression of inland bower birds) instead of exercising their voices in mimicry. And the tooth-bill stands as an amiable link: it mimics, it plays, but it does not build a bower.