WILD LIFE IN NEW ZEALAND

Otago Witness, Issue 3403, 4 June 1919, Page 61

WILD LIFE IN NEW ZEALAND

By the Hon. G. M. Thomson, F.L.S. No. XLVIL—CUCKOOS. The parasitic habit is extraordinarily common in the animal, as it is in the vegetable kingdom. The lower down we seek in the scale of created organisms the inoro frequently do we meet with it. The strictly scientific definition of a parasite is an animal or plant which lives in or upon another, and takes its' nourishment from the host. In practice the term is used more indefinitely, and it is sometimes difficult to draw the line between parasitism and commensalism. It is easy to illustrate this if we take examples from the great group of the Crustacea, in which both phases off existence are very common, and which snow every intermediate condition. Thus in the common mussel of our sea coast there very frequently is. to be found inside the shell and inside the mantle of" the molusc a small, round, rather soft-shelled crab. Only females are found in this sheltered residence, the males being much smaller, harder-shelled, and of a roving disposition. The crab lives inside the mussel, and apparently eats some of the food' which the mollusc receives when it opens its shell. - It does not appear in any way to injure the mussel; nor is it easy to suggest any good it can do to the mussel. The benefit seems to be all on the side of the crab, which lives a secure and sheltered life, apparently gets enough to eat, or it would not stay where it is, and can dispense with the hard coat of mail which other crabs find to be essential for their safety. This is a case of pure commensalism. We can parallel it in the vegetable kingdom among the epiphytes which live on tree trunks, and take their nourishment from the atmosphere. On the bodies of many fishes are often found fairly large, flattened Isopod crustaceans, popularly known as fish-lice. These live on the outside of the fish, to which they cling by their strong claws, and they either attack the skin and flesh of the fish, or act the part of a sort of scavenger, clearing away loose and dead tissue, scales, etc. That they irijhre the fish to some extent is manifest, for when they are at all numerous the fish get into very bad condition. These are a sort of partial parasite, for they can and often do live a partially independent life, and forage for their own food. Lastly, in many fishes numbers of muchdegraded forms of crustaceans —so degraded in structure that they occasionally appear worm-like —occur imbedded in the tissues of the host. These are complete parasites, living practically all their lives m and on the animal with which they are associated.

When we consider such a highlydeveloped group of organisms as the birds, we do not look for, nor do we find, anything approaching true parasitism. 'But we do meet with a partial form of it in the cuckoos, and the manifestation of it is so curious that it has seized the popular imagination. All cuckoos do not. exhibit the -parasitic habit, but the section to which the familiar European cuckoo and one or two native belong do. The name is derived from the peculiar call of the common British species. This well-known bird has long been recognised as the herald of spring in the north, and one of the early English songs, which dates from about'l2so a.d., begins:

S inner is icumen in, Lhude sing cuccu. G-roweth Bed, arid bloweth med. And springth the mid© mi — Sing cuccu! John Lyly, writing three centuries later, closes his " Spring's Welcome " -with the lines: . Hark, how the jolly cuckoos sing Cuckoo! to welcome in the spring. And many another poet, right down to our own times, has sung of this bird as spring's harbinger. I well recall a lovely spring forenoon when I was a boy, and first heard what was afterwards a familiar note. We were living in the neighbourhood of Edinburgh, and were having early dinner —I remember it was a Sunday,—when the call of a cuckoo resounded from the elm trees just outside the garden fence. It was the first time any of us youngsters had heard it, and we were so excited that we forgot all ceremony, and jumped from the table, trooping outside to see, if possible, the welcome stranger. In later years, when living in the neighbourhood of London, I learned to imitate exactly the call, and, lying under the umbrageous oak trees, could always bring the cuckoos, into the branches above me if there Avere any about.

The curious feature about this bird's life habits is that it makes no nest for its future brood, but entrusts its. eggs to the nest of another —and always a much smaller bird —to be hatched, and the young to be reared by foster-parents. The female European cuckoo is said to lay eight eggs in a season, but she never places more than one in each nest. The former popular idea of the parasitism of these birds in the Old Country used to be that the young cuckoo, when sufficiently grown, swallowed his little foster brothers ami sisters, and his wickedness was held up as an awful example to ungrateful children, who became a burden and shame to their old parents. What actually happens is that, as the young cuckoo grows and quickly begins to fill the nest, he throws hi? foster brothers and sisters out to perish of cold and hunger, and takes all the food that is meant for the nestfnl. Though this all relates to the. European species, it agrees so much with what we know of our own birds that I transcribe Mrs Hugh Blackburn's account of -what she actually saw. The nest (which we watched last June after finding the cuckoo's egg in it) was that Of the. common meadow pipit (tit-

lark, mosscheeper), and had two pipit's eggs, besides that of the cuckoo. It was below a heather bush on the decilivity of a low, abrupt bank or highland hillside in Moidart. At one visit the pipits were found to be hatched, but not the cuckoo. At the next visit, which was after an interval of 48 hours, we found the young cuckoo alone in the nest, and both the young pipits lying down the banii, about lOin from the margin of the nest, but quite lively after being warmed in the hand. They were replaced in the nest beside- the cuckoo, which struggled about till it got its back under one of them, when it climbed backwards directly up the open side of the nest, and hitched the pipit from its back on to the edge. It then stood quite upright on its legs, which were straddled wide apart, with the claws firmly fixed half-way down the inside of the nest among the interlacing fibres of which the nest was woven, and, stretching its wings apart and backwards, it elbowed the pipit fairly over the margin so far that its struggles took it down the bank instead of back into the nest. After this the cuckoo stood a minute or two, feeling back with its wings, as if to make sure that the pipit was fairly overboard, and then subsided into the bottom of the nest. S.S it was getting late I replaced the ejected one and went home. On returning next day both nestlings were found dead and cold out of the nest. I replaced one of them, but the cuckoo made no effort to get under it and eject it, but seated itself contentedly on the top of it. All this I find accords accurately with Jenner's description of what he saw. But what struck me most was this: the cuckoo was perfectly naked, without the vestige of a feather, or even a hint of future feathers; its eyes were not opened, and its neck seemed to weak to support the weight of its head. The pipits had well-developed quills on the wings and back, and had bright eyes, partially opened; yet they seemed quite helpless under the manipulations of the cuckoo, which looked a much less developed creature. The cuckoo's legs, however, seemed very muscular, and it appeared to feel about with its wings, which were absolutely f eatherless, as with hands; the spurious wing (unusually large in proportion) looked like a spread-out thumb. The most singular thing of all was the direct purpose with which the blind little monster made for the open' side of the nest, the only part where it could throw its burden down the bank. I think all the spectators felt the sort of horror and awe at the apparent inadequacy of the creature's intelligence to its acts that one might have felt at seeing a toothless hag raise a ghost by an incantation. It was horribly 'uncajiny' and 'gruesome.' " The reason and the origin of this extraordinary habit are difficult to account for. The eggs are various in colour, "from a white speckled egg like that of the water wagtail, or the dark brovn mottled egg of a lark or pipit, to the blue egg of a hedge sparrow. They generally assimilate to the eggs of the foster parent to a certain extent. It is proved that the female cuckoo lays her egg on the ground and conveys it to the chosen nursery in her bill. The foster parents never seem to resent the intrusion of the stranger, or to notice their consequent losses." Turning now to New Zealand, we find that two species of the family visit,these islands—the shining or bronze cuckoo (Ohalcococcyx luoidus), which comes over the sea every spring from Northern Australia, or even further north, and the longtailed cuckoo (Urodynamis taitensis), from Polvnesia.

The shining cuckoo is a small bird, only about 7in long. It is a very conspicuously marked species, the whole upper surface being of a metallic bronzy-green colour, while the lower surface is white, barred with brown, this extending round the eyes and also to some extent over the forehead. It appears regularly in the far north in the latter half of September, and reaches the South Island early in October. The birds stay here till the beginning of January, and leave the north towards the end of the month or early in February. The range of the species is not accurately known. It breeds in New Zealand, the Chathams, and Norfolk Islands. It has also been met with at -Cape York, in Northern Queensland, and Hutton considers it probable that its winter home is in New Guinea. This little bird has a rather nice song or call—a succession of long, silvery notes according to Buller. It has also considerable ventriloquial powers, so that when quite close to a listener it can call as if it were very far away.

These birds feed chiefly on caterpillars, and should therefore be welcome to the farmer and the gardener. In regard to their breeding habits, the little grey warbler (Pseudogerygone igata) is the chosen foster parent—a bird about a third of its size. " The nest of the little bird is of the shape of a. soda-water bottle; it is Bin long, and about 4in in diameter at its widest part. The entrance, which is at the side, is almost across, and about liri perpendicularly. The upper portion of the nest somewhat overhangs the aperture, forming p. kind of hood. It would be almost impossible for a ouckoo to enter the nest and lay the egg in it." Though the fact has not been observed, it is almost certain that the cuckoo lays its egg on the ground and then transfers it by means of its beak into the fosterparent's nest.