Chapter XXXVII.
Reconsiderations.

Before proceeding to the consideration of certain aspects of migration, it will be convenient to clear the air of misconceptions as to the effect on aliens of importation and acclimatisation. Not infrequently it has been assumed that in some measure capture, confinement, and the manipulation of man has altered, not the nature of the specimens captured—that is likely enough—but the nature of the offspring born of them; that, free in a new land, the trammels of civilisation still cling to and hamper their country-bred descendants. Such a belief would largely detract from the interest attaching to the journeyings of the many aliens that have passed through Tutira. It is not true; to the animals themselves, and indeed in the final result, the sails of a ship are no more than a prolonged gale, the deck of a steamer no more than a drifting timber mass, a floe, a fragment of sud; whether blown from their quarters by stress of weather, and borne abroad by currents of air, or whether trapped, railed to port, and shipped over thousands of miles, their descendants start level in the race of life.

The Wax-eye.

The wax-eye (Zosterops cœrulescens), actually seen to have arrived on the Mahia by the Bishop of Waiapu, and the sparrow, known to have been liberated from cages at Auckland, have each arrived in New Zealand since its proclamation as a British possession. In a page 364 sense the arrival of the one was natural, the arrival of the other artificial, though the terms may give us pause, since every interference by man with the normal course of events may also be called natural. At any rate, once landed in New Zealand, the two breeds were essentially on the same plane. Each had reached its destination in its own way—the wax-eye by pinion and plume, the sparrow by sailcloth wings. Whatever the difference in manner of arrival may have been, once landed in New Zealand the breeds were on a par as to the future. Each was beyond the direct influence of man,—outside his pale, free to select the route of its wanderings, its rate of increase, its climate. In truth, we may eliminate from our minds the long sea-voyage, the habitation of ships, the cramped confinement below deck. If we choose to do so, we may consider that the sparrow, blackbird, deer, and weasel arrived in New Zealand during the 'sixties, 'seventies, and 'eighties by a series of nearly connected islands, since submerged. At any rate their goal once attained, fullest liberty awaited them; they were free to pursue a future unshackled by the past.

The behaviour of aliens “wild” in a strange land can neither be compared to the seasonal migration of continental areas, nor on the other hand be passed over as mere incursions, mere irruptions, such as those of the sand-grouse, or the lemming, that ebb and leave no lasting mark. The treks of our aliens have a certain original place in the annals of migratory movement; they possess, moreover, the interest that attaches to an experiment which cannot be repeated. Conditions obtaining in New Zealand in the 'fifties, 'sixties, and 'seventies no longer exist. The world does not now contain a continent or a great island still virgin, still unmanned.

The particular history of certain aliens has been described. Two main facts stand out: the first, that amongst certain of the birds there still survive blind and broken traces of some sort of seasonal impulse, reminiscences, confused and indeterminate, of gatherings for flight. On Tutira I have again and again witnessed the assemblage in autumn of parties and congregations of birds, of petty local migrations. Black-birds, greenfinch, and thrush gather in flights great or small; they travel somewhere for some purpose, though the whither and why will remain unfathomed until individual birds are marked and watched. The second fact standing forth pre-eminently is, that many of the aliens have moved at the prompting of a genuine migratory impulse.

New Zealand is in shape a long strip of territory pointing north and south. It central ranges are rugged and high; the trend of settlement accordingly has been along the seaboard: settlement has moved north and south, not east and west. The line followed has been followed for the common-sense reason that it is easier to move parallel to a range than to traverse its heights. North and south has been the line of least resistance selected in turn by man and beast, first by Maori, later by European, and last by his introduced mammals and avifauna.

That has been the general direction followed; particular modifications have been the hill-top, the coastal and river-bed routes. The way of each species, moreover, human or brute, has been affected by special idiosyncrasies and predilections.

The wish for warmth has confined the Maoris, the earliest aliens of all, to the northern portion of the North Island, to coasts and estuaries elsewhere, and in the interior to the thermal region. To a later alien, the white man, ports and harbours have been essential. The Anglo-Saxon, a hardier breed from a colder climate, has spread not only along the coasts and over the northern parts of the North Island, but over the interior everywhere of both islands.

Aliens of a lower rank in the scale of nature have also followed diverse routes, influenced by diverse desires. Breeds sedentary in their original habits, as might have been expected, have shown similar characteristics in New Zealand. Others have felt in fuller degree the instinct that bids a race move forward. From treks of the latter sort some curious facts may be gathered. They exhibit a fire of restlessness, a passion of progress bred into the fibre of every member of the moving mass.

Rabbits turned down in the Wairarapa after a few seasons became a curse, increasing and multiplying until many of the local squatters were eaten out, their stations left desolate, and they themselves ruined. Between that period and the date of their invasion of Tutira the hand of man has lain heavy upon the rabbit. Everywhere also its advance has been retarded by the attacks of harriers, moreporks, and wekas, working not for eight hours a day like man, but for twenty-four. Rabbits nevertheless have forged ahead thinly on a vast front, reaching Tutira almost simultaneously by the hill-top, by the coastal route, and by the line of the human highway. There was no strip of open land page 366

Rabbit Advance checked by River.

page 367

Rabbit Advance. Stock Route used only until Northern Exit discovered.

page 368 from coast to mountain ridge along which during the 'nineties rabbits were not filtering towards Hawke's Bay—towards Tutira. It was an invasion which, however disgusting to the sheep-farmer, was full of interest to the field naturalist.

The physiography of Tutira has been described,—a series of slopes precipitous to the west, tilted gently to the east, and fissured by ravines. It was a pattern well adapted to illustrate the rabbits' desire to follow a definite direction. The invasion moved from south to north, the ravines on the other hand ran east and west, at right angles, that is, to the line of trek. On the high ranges of the west these natural obstacles to progress were particularly formidable. On many the gorges began within a few chains, sometimes within a few yards, of the ridge-cap. Only rabbits, therefore, moving along the very summit could proceed. All others found their progress barred, discovered themselves on the brinks of precipices, many of which were fifty or sixty feet in height. It was impossible for them to remain for any length of time on barren cliff-edges. By natural enemies, necessity of food-supply, fear of the open, and lack of burrow accommodation, they were eventually forced either once more to the summit or downwards to more accessible country. Thus barred from their selected line of progress many were forced downhill, and reached after a time the great pumiceous trough of the run.

Through this, then, bleak forbidding country ran east and west the main stock-route of the station, the trail by which sheep are driven to the distant paddocks aud mustered homewards for shearing. It varied in width from five to ten yards, and for miles passed through fern-lands bare of grass. Now it might have been anticipated that rabbits thus finding themselves on an open road, a smooth space hedged in by deep bracken, would have been content to accept it without question. Far from this happening, however, the east and west stock-route was used no longer than was necessary to find northward leading exits. No pig-trail however narrow, no sheep-track however overgrown, no fence-line however little trodden, that branched off northwards, was neglected. Rabbits caught by the contractor and his trappers were found in the extreme northern points of the blind spurs. On such spots the vermin stayed, blocked by impassable ravines, never attempting, as far as could be judged by signs, to retrace their path. Spots unexplored in former times, even by shepherds, even by myself whilst pig-hunting in early page 369 days, had now to be diligently searched for rabbits. They were always to be discovered on the northernmost extremities of northern-running spurs, never on the southernmost extremities of southern - running spurs.

On Tutira the plague has from the first been kept in check by contract, a most satisfactory system to all concerned. The duration of the original contract, which has been from time to time renewed, was for five years, a great proportion of each year's payment being withheld until the termination of the periods. Responsibility, moreover, for all fines and penalties that might be levied on the owner by the Hawke's Bay Rabbit Board was also accepted by the contractor. He had a personal interest, therefore, in the matter. One of the most practical proofs indeed of the rabbit's determined northern movement was the anxiety with which he watched the runs south of the countryside over which his agreement extended, and his indifference to lands north of Tutira. These were times when the rabbit was still an unknown quantity, when his advent was still viewed with little short of consternation. I knew, therefore, and sympathised with my contractor's uneasiness. Riding with him, I used to hear many aspersions as to the carelessness of the poisoning, trapping, and shooting work of southern neighbours. As to the conduct of stations north of Tutira he cared not a jot; their rabbits were not on his mind. As he phrased it, “the brutes are through us now and will never return.” They were moving north.

Under the contract system described it may be supposed that no considerable number of rabbit congregations for long remained undiscovered. When, however, from time to time one such was first found, it did not seem to have increased beyond certain numbers. Whenever litters had become fit to move forward, apparently they had moved forward. There had never occurred multiplication to the limits of the local food-supply. These settlements, usually oases in manuka thickets, have been again and again trapped, shot, dogged, dug out, and poisoned; the rabbits inhabiting them annihilated. They are, in fact, caravansaries, favourite halting - places on the line of march, utilised by successive relays of rabbits, again and again restocked by fresh bands passing northwards.

Other illustrations of the resolute pursuit of a certain chosen line, and of the migratory fever possessing both old and young of the breed page 370 in motion, are afforded by the advance of several of the alien avifauna, by the behaviour of the blackbird, thrush, and chaffinch in particular. For years the blackbird and thrush passed through Tutira without perceptible increase of local birds, the two broods reared each season vacating the station, young and old alike merging themselves in the current of advance.

Self-interest is a trait in human nature ever alert and watchful; men's observations are whetted, their recollections sharpened, by events that harm or help. My contractor's jubilant exclamation in regard to the rabbits, “the brutes are through us now and will never return,” was prompted by observation of certain facts in which he himself had a personal interest. The spread or rather settlement of the blackbird and thrush likewise became in a minor way a personal matter to every settler, shepherd, and station-hand on the east coast. Few, indeed, noticed their arrival or their habits and customs during the early years of their appearance. It was only when after a certain lapse of time that loss of ripe fruit from the wild cherry-groves, theft of raspberries and grapes from the garden, became but too obvious, that their presence was fully realised. Fruit which had ripened was no longer suffered to ripen.

Details of the arrival of the first blackbird and thrush have been given. They reached Tutira about the same time, in '91. Two years later considerable numbers were temporarily resident in spring, breeding with us. Now, had these station-born birds remained and bred, their descendants again remained and bred, the numbers both of blackbird and thrush would have increased so greatly that our cherry-groves and gardens would have been despoiled many seasons sooner than did actually happen. Had there been no forward movement, they would have locally multiplied like the price paid for the successive nails in the horse's shoe. As a matter of fact, no harm was done until ten or twelve years later. Since that time cherries have never been allowed to colour beyond a bright red; in olden days they remained for weeks, sweet, black, and wrinkled, on the laden trees.

Another fact worth noticing in the blackbird and thrush migration is its narrow width, the advance of young and old alike along a line within limits confined to the coast. For years later than the spoliation of groves on the route of march, the cherry plantations at Waikaremoana, inland from Wairoa, and at Maungaharuru, inland from Tutira, remained intact and continued to mature dead ripe fruit.

Other evidence of the non-stop character of the blackbird and thrush movement is the scant attention accorded to it. Had these birds, for instance, stocked Waiapu to the limit of winter food-supply—snails, worms, and insects—ere proceeding to Poverty Bay; had they stocked Poverty Bay to its limit of food-supply ere proceeding to the Wairoa, and so continued southwards down the coast, the striking contrast between districts swarming with birds and districts entirely void of them must have been appreciated by the most unobservant; local papers would have been full of letters from sentimental folk regarding the singing of feathered choristers from the homeland. There would have been bitter complaints from the resident growers of small fruit, for the blackbird and thrush by no means confine their depredations to cherries; every crank in the community would have been in favour of importing owls, hawks, eagles, and for aught I know, boa-constrictors, vampirebats, and tigers to cope with the pest. The fact is, that our acclimatised birds have stolen upon us. Their advance has been so gradual, and at first so thin, that except for an observer here and there it has remained unnoticed, unchronicled. In a practical community little or no attention has been excited by the spread of imported aliens until, as has usually happened, they have become a nuisance.

About the chaffinch facts of a similar complexion are available. This species, it will be remembered, moving at first by the coast-line and afterwards by a river-bed route, had been first seen in Poverty Bay and later in the Wairoa before the earliest specimens reached Tutira in the beginning of the present century. Its arrival had been confidently anticipated; an especially keen watch had been kept there and elsewhere for the bird. Following its discovery at the apex of the Poverty Bay plain, I spent several weeks of two winters' quail and pheasant shooting in the Hangaroa district, five or seven miles inland from the coast as the crow flies. There were no chaffinches there when they had already reached Wairoa on the coast. There were still none to be seen at Hangaroa when the birds had penetrated Tutira, had passed through Petane, had moved onward as far as Havelock North. The trek, following the river-bed route, had struck the coast and then hung closely to it. It appears, indeed, to have been a mere lance-head thrust into the unknown.

The chaffinch, like the blackbird and thrush, passed through Tutira long before the limit of food-supply was reached. Small travelling page 372 parties, caught perhaps on the move by the impulse to build, seemed for several seasons, after the vanguard had reached the run, to breed, if not semi - gregariously, then at any rate thickly, in comparatively limited areas, thickets of tall manuka and the like. These areas in later years contained fewer pairs, sometimes, indeed, no birds at all, though covert, breeding accommodation, and food - supply were each and all, as before, superabundant.

Again, I think, there can be no doubt that old and young alike were drawn into the current of migration. There is no alternative by which the disappearance of broods reared on the line of march can be accounted for. It is, at any rate, as certain in regard to the chaffinch as in regard to the blackbird and thrush, that the advance was not solid, that there were not multitudes of birds north of a given line, whilst south of it not a specimen was to be found.

Consideration of the weasel's passage along the east coast shows more clearly than any other migrant movement that there exists in each unit of the mass, not only in its mature members, but also in those born during the journey, the instinct of adventure. The proof is complete; it lies in the fact that the pest passed through the district and disappeared. In this case we do not need to deduce and infer how the young have gone forward. We know they did go forward, for none of any age, young or old, remained. The three years' irruption of weasels through Tutira, and the district lying between Napier and Gisborne, resembled the progress of a comet across the heavens, the tail following the head, and at last leaving the sky once more clear. The invasion rolled itself up like a scroll; it came and went like a thunderstorm; ominous rumblings and mutterings, rumours of bitten babies, slaughtered fowls and lambs, lightning flashes from the Yellow Press, curses on the squatter class, heralded its approach. Then it rained weasels; they poured along the roads. There was a dissipation of the clouds; once again the sun shone bright through a blue sky—the weasel was a thing of the past, and remained so for very many years.

In the migratory movements of the starling and minah there is considerable proof of a general nature as to inclusion of young birds in the advance. In the march of each of them, however, there has been a parasitic clinging to man which places them in a different category from the weasel, rabbit, blackbird, thrush, chaffinch, and page 373 redpole. The trek of the sparrow through the very heart of the North Island is second to none in interest, but he followed the track of man—the king's highway.

Speaking in general, after a time the overpowering impulse to move onwards on a certain line, never to cease to follow a leader, begins to wane. The migratory fever dies down; a check occurs in the march forward, a check sometimes permanent, sometimes temporary. In either case every link in the long chain of migration is at once affected. The check may be compared in its action to the stopping of the engine of a train, when each carriage is in turn affected, or perhaps better, to the damming back of a stream. The sluice is closed, the stoppage of the head-waters stills the draw of the current behind until at last all seems quiescent, or—to continue the metaphor—until the dam breaks, giving way at last to irresistible pressure, until in one burst the waters once again rush forward.

The rabbit, for example, after only three or four seasons, began to settle on its tracks, its earnestness of endeavour to get forward became less keen. Its vanguard had reached the deep swift-flowing Mohaka. The presence of that barrier had been communicated backwards along the whole line, not in any occult mysterious fashion, but, I imagine, simply by a cessation of forward movement by the leading rabbits, by the leading files of rabbit—their halt reacting on the second file, that of the second on the third, and so on through the miles-long chain. It is for this reason that there is no huge immediate piling-up of rabbits against a newly-erected rabbit fence—the news of a check is automatically passed backwards along the line. There seem to be three phases in a migratory movement—the first, that of follow my leader, old and young alike moving onwards in a definite direction; the second period begins after the van has sustained a check, when the individual links of the living chain begin to breed circlewise, when they begin to stock the country in breadth as well as in length; the third, of which I have seen one notable example, is the bursting of the containing barrier and the sweeping bare of the breed from grounds previously overcrowded and overstocked.¹

The period between the first arrival on Tutira of the goldfinch and the time when a marked increase took place in the breed—when the station began to be stocked by the station-bred birds—was also noticeably brief. The goldfinch in its northern advance during the 'eighties page 375 had struck a barrier of another sort—a barrier of uncleared land, a barren countryside covered with scrub and bracken, where the thistle was unknown—a consequent insufficiency of food.

The period during which the migration of the redpole continued through Tutira was also brief. The barrier to the southern progress of the redpoles was of an exactly opposite sort—not bad land, but good land—unpropitious environment to a wild country breed,—vast stretches

Goldfinch passing through “broken in” country—checked by unhandled bracken and scrub.

Redpole movement checked by grass-lands.

of grass-land completely cleared of scrub, lacking both food and nesting accommodation.

On the other hand, the passing of the blackbird and thrush through the station was prolonged for years. There was nothing to check the current of their flow for scores of miles beyond Tutira. There was every inducement to proceed through a warm, highly fertile coastal belt, amply supplied with shrubberies, plantations, and gardens.

The duration of the weasel trek through the run was more brief than that of any other aliens; rivers unbridged proved no barrier—he page 376 rushed through good and bad alike. Without a base, however, he perished from insufficient numbers; like the seed in the parable, when the sun was up he was scorched, and because he had no root he withered away. I could never trace the movement beyond the southern edge of the Poverty Bay plain. It passed along the east coast like a comet through the heavens, fading away in front and leaving no trace behind.

The origin of movements seems to be congestion. Where there is no great increase of numbers, as in the case of the pheasant, the quail, the rook, and other species, there is no accentuated movement. Spread is almost fortuitous, a merely negative pursuit of the summum bonum of animals—food, shelter, and breeding accommodation. On the other hand, species whose rate of increase is great multiply about the spot of liberation until the limit of food - supply, clean quarters, and breeding accommodation is reached. The normal spread, perhaps, of a species is circlewise from a centre, perhaps also it would continue with equal speed in all directions for all time were exactly similar environments anywhere to be

Mob of travelling sheep.

discovered. Sooner or later, however, weather conditions, physical and geographical barriers, limit such circular extension. Where a barrier is touched in any one quarter, pressure of growth is transferred to other segments of the circle,—its original shape is lost. At last, where resistance is least great, the living contents break forth. It may be that disinclination to move persists for a considerable period after the limits of comfort have been reached. There is a dread of new conditions, greater or less according to the nature of the breed, which prevents many species from severing widely the bond of one another's company. They prefer discomfort to disintegration; leadership is uncoveted—it is a post of danger and dread,—the desire of each is not to lead. As all, however, cannot be followers, the position of danger is distributed over a large number of individuals. A flock of sheep, not yet listless with dogging or careless on a well-known road, travels with a head formation rather blunt than broad, page 377 such as water carries when poured on gently sloping even ground. Actual leadership is taken up moment by moment by different sheep, each temporary guide when a few inches ahead becoming scared, pausing, and letting his neighbours on either side precede and accept in their turn the responsibility and peril. By this method of advance no individual offers too prominent a mark, each feels himself able in a fraction of time to plunge sidelong into the mass, to lose himself in comfortable nonentity. If the sheep domesticated for hundreds of years cannot forget this sense of impending danger, wild creatures dare not for a moment cease to suspect the unknown. This dread it is, I think, which keeps large companies of animals voluntarily confined, penned close in limited areas for considerable periods. The absolute numbers of a congested horde are unimportant. It is the relation of numbers to environment that decides the genesis of the trek. The numbers of the rabbit in the Wairarapa, and of the goldfinch in lower Hawke's Bay before their advance began, must have been immensely greater than those of the sparrow or of the blackbird or thrush in Auckland. In the case of the rabbit and of the goldfinch there was room for the enlargement of the circle and a consequent postponement of the initiation of the trek. On the other hand, where the locality of liberation was limited in space or feeding-ground, as in the case of the sparrow, blackbird, and thrush, the time during which the circle could spread normally without striking barriers meteorological, physical, and geographical, was sooner reached, the movement of migration more quickly precipitated.

We have imagined a deep distrust and suspicion of the unknown sufficing to hold together a congregation of aliens in a strange land—sufficing to retard migration until further expansion has been blocked, this fear of what may lie beyond counteracting the disabilities of less clean feeding-grounds, less ample breeding accommodation; we have imagined the congestion becoming intolerable until the uneasy horde at length breaks forth. The begetting force of the actual moment of migration can be conjectured with a fair degree of likelihood; hardly a hint would be required. A premonition of that deep inherited kind we call instinctive would have permeated the inert and uneasy mass that movement was in the air; change of ground would have been long anticipated; the horde would be in a state of unstable equilibrium charged with an instinctive restlessness, expectant as duck after dusk for the signal to rise. Equality, however, amongst the lower creatures page 378 is no more existent than amongst men. There are no do not degrees of fearfulness, of timidity, though perhaps as infinitesmal as the differences in height betwixt the lilliputian monarch and his subjects. Thus the actual incitement to move would, like the leadership of the travelling flock of sheep already cited, be shared by many simultaneously, or if that be impossible in time, then one of the migrants—a Moses about to lead his congregation into the wilderness—would exceed his fellows in celerity of rise by as little as the centre of a taut inch of thread differs in straightness from its extremities.

There are several lesser matters that may also be reconsidered,—sex of leaders, scouting, joint migration, climatic conditions, and general reasons for failure or success in the acclimatisation of aliens.

As to the first, the sex of leaders, I have little evidence to offer except in regard to rabbits. The pioneer of the advancing wave—the first rabbit taken on Tutira—was a male; of the first two or three dozen taken after the vanguard had appeared all were males. Amongst the first hundred or two, males still largely predominated.

In regard to scouting, there have occurred in my time at Tutira a couple of instances of single birds reappearing—reappearing, moreover, almost exactly twelve months later, and almost exactly on the same spots. The first case was that of the goldfinch seen near the wool-shed, and seen again on the same spot in the following season. The second instance was that of the minah, which, crouching close against the wire-netting of the newly completed hen-run, attempted to associate with the fowls. A year later the bird reappeared, again sitting close against the wire-netting exactly, as far as we could judge, on the site previously occupied. The very attitude was similar on the two occasions, an unwonted attitude for a species that under normal conditions never sits or crouches on the ground. It bespoke exhaustion, fear, and friendlessness. Like the rabbit which consorted with the Tangoio turkeys, this minah seemed glad to scrape acquaintance with any living thing. I feel as sure as a man can feel not dealing with marked birds that in each case it was the first seen individual revisiting us. The odds are enormous against another bird reaching by chance precisely, exactly, the same spot at the same time of the year on two sequent seasons. Were these birds scouts? Were they despatched as bees are said to be sent forth to discover quarters for the expected swarm? At any rate, both the goldfinch and minah appeared, presumably returned whence they came, and reappeared. After the page 379 lapse of a year they had remembered the route and repeated the experiment.

As to the joint migration of certain species, both Mr Williams and his brother have always maintained that the blackbird and thrush travelled together. They were first noted “at the same time” in the Waiapu and Poverty Bay; “within a short time of one another” in the Wairoa. At Tutira also the two breeds were heard and seen within a week or two of one another. If they had not travelled together, it is more than remarkable how evenly the species had kept step. The same may be said of the arrival of the chaffinch and the redpole many years later. If nothing more, it is a curious coincidence that two new aliens should twice have reached Tutira within a few days of one another. Personally I have no doubt they travelled in each other's company.

Of foreign species imported into New Zealand there have been more failures than successes. Many have perished immediately, like the nightingale, redbreast, and sand-grouse. In Hawke's Bay, black-game, partridge, and yellow wagtail seem never to have reached a second generation. The initial failure of the blackbird and thrush in Hawke's Bay is the more remarkable in view of their proved suitability in after years. Small numbers however only were freed. I am given to understand too that liberations were almost direct from the cages. Probably too the birds were cramped and gross from want of exercise; lastly, though liberated in localities cleared of cats, the destruction of rats and predatory native birds had been overlooked. Some species, again, after initial success, have disappeared, like the brown linnet; others, like the pheasant, the Australian and Californian quail, have for a considerable period increased, then begun to die away. The fate of game-birds has naturally attracted the largest share of public attention. Partridges have again and again failed, not only in Hawke's Bay, where their acclimatisation has been on too meagre a scale for much chance of success, but also in localities seeming to offer ideal conditions. The reason of the failure in such districts seems to be other than initial want of numbers or disturbance by vermin. They have perished, as in certain western islands of Scotland imported grouse have died off, and perhaps for the same reasons. For the decline of the pheasant many reasons have been assigned. Climate and vermin have been blamed, yet neither wholly account for the facts. Pheasants, we know, did in Hawke's Bay flourish and increase for a considerable period; neither climate nor predatory natives, such as the weka, hawk, page 380 or morepork at first prevented their multiplication. Search must be made for the lack of some formerly helpful factor; that factor was the absence of alien insect-eating birds. The decline of the pheasant synchronised with that advent of small birds whose rapid increase in the 'seventies “had been viewed with considerable alarm” by the Hawke's Bay Acclimatisation Society. The fact is, that owing to climatic conditions any great success with the pheasant was from the first fore-doomed. It was only because of an unlimited supply of the most suitable and nutritive chick - food that the breed had been able to multiply even temporarily. Although Hawke's Bay “busters” must have always been detrimental, yet owing to the enormous supply of insect-food this disability had been more than counterbalanced for the time. It must be recollected, too, that about the date of introduction of the pheasant, the development of Hawke's Bay was proceeding apace. Each year on each sheep-farm large areas were being grassed; swamps were being drained; even a certain amount of ploughing done. Insect life during that period was increasing out of all proportion to natural checks.

Grasshoppers and caterpillars, native and alien, had multiplied on the succulent foreign grasses and fodder-plants by hundreds of millions. According to old residenters, they were plagues in the land. The pheasant had lived without competitors in the struggle of life; under more strenuous conditions the bird failed to hold its own. The breed is one hailing from a dry country; the chicks are peculiarly susceptible to cold and wet. With the deprivation of unlimited insect-food, for which formerly the hen had hardly to seek, the danger period to the chicks was extended. The brood was trailed over greater areas; the youngsters were not so fully fed; the number of eggs laid was less; in case of accident, perhaps, a second nest was not attempted. When account is taken of the care devoted by keepers at home to pheasant chicks, the special foods supplied to them, the short grass in the neighbourhood of the coops, and lastly, the absence of torrential rains, instead of wonder at the pheasant's decrease there should be marvel at the continuance of the breed at all in Hawke's Bay.

In this and previous chapters I have collected such evidence in regard to migratory movements as I have been able to gather from species that have crossed Tutira. The gist of it may be compressed into a few sentences. My beliefs are that where imported species, page 381 afterwards proved to have been adapted to their environment, have at first failed, it has been due to liberation in too scanty numbers; that aliens freed under these circumstances have scattered so widely and wandered so far apart from one another that in some cases they have lacked mates and in others have fallen victims to vermin; that individuals thus strayed associate with creatures in no way akin to them; that species successfully acclimatised increase circlewise until containing barriers are reached; that a migration once begun follows the line of least resistance, as may be determined by the leaders; that the line of trek having been decided upon, it is followed by all members of the horde, young or old; that broods or litters born by the way also pass forward; that rapidity of migration is determined by the speed of the leaders; that a check in front is communicated with remarkable celerity to the entire migrant chain; that species on the march retain the special habits and idiosyncrasies which mark them in quiescence; that the leaders are probably males; that certain alien species have travelled in company with one another; lastly, that possibly the single goldfinch and single minah cited may have been scouts—that, at any rate, they were not leaders of a trek already in motion.

¹ At Peel Forest, South Canterbury, where in the early 'eighties I was cadeting, I was witness to what I have described as the third phase in a migratory movement. At the date mentioned hares swarmed about the westermost end of Peel Forest run. There were hundreds, there were thousands of them. During the breeding season I have counted seventeen and eighteen running amorously together. They were migrating westwards, and had reached a temporary cul-de-sac, hemmed in by mountains and forest on the one side, by a huge snow-fed river—the Rangitata—on the other, whilst directly across the westward exit lay the hamlet of Peel Forest. Two or three seasons later, upon my return, there was hardly a hare to be seen:

Hares east of village.

Hares west of village.

the impulse to move had swept the locality bare, the barrier had been burst, the hares had proceeded on their way.

Shooting-parties held in one decade east were in the next held west of the gorge.