THE RELATION OF BIRDS TO AGRICULTURE IN NEW ZEALAND.

New Zealand Journal of Agriculture, Volume XXVIII, Issue 3, 20 March 1924, Page 166

THE RELATION OF BIRDS TO AGRICULTURE IN NEW ZEALAND.

VIII. THE PIGEON, KIWIS, RAILS, AND SHORE-BIRDS.

J. G. MYERS and ESMOND ATKINSON,

Biological Laboratory, Wellington.

THE PIGEON.' . That family of the order of pigeons which includes the fruit-pigeons contains no more beautiful birds, even among its numerous tropical members, than the New Zealand pigeon; sometimes known by its onomatopoeic name of “ kuku ”or “ kereru.” No description of its magnificent plumage, with the coppery purple of the back and the metallic green of the breast set off by the pure-white underparts, nor of the unmistakable clap-trap of its wings in flight should be necessary to New Zealand readers, although it is too true that there are large areas, even of bush country, where owing to the inroad of shooters and of weasels the pigeon is no more to be seen. Sufficient was said in the second article of this series to indicate the high value of berry-eating birds and of the pigeon in particular in the economy of the indigenous forests. For a detailed description of the food of the pigeon at various seasons of the year Buller’s account,, drawn up from ample experience in the days when this bird had not yet begun to decrease, is hardly to be improved on. We quote it here to indicate the large number of forest species with which ’the pigeon enters into food relations :

“ In the spring and early summer it is generally very lean and unfit for the table ; ■ but as autumn advances and its favourite berries ripen it rapidly improves in condition, till it becomes exceedingly fat. It is esteemed most by amateurs when feeding on the mast of the miro (Podocarpus ferruginous), which imparts a peculiar richness' to the flesh. In January the berries of the kohutuhutu (Fuchsia excorticata), poroporo (Solanum aviculare), kaiwiria (Hedy car ya arbor co), puriri (Vitex lucens}, mangeao (Litsaea calicaris), and tupakihi (Coriaria ruscifolia) constitute its ordinary bill of fare. " From February to April their place is supplied by those of the tawa (Beilschmiedia taw a),. matai (Podocarpus spicatus}, kahikatea' (Podocarpus dacrydiodes}, mapau (Rapanea Urvillei), titoki (Alectryon excelsum), and maire (Olea spp.). It is worth remarking that in localities where it happens to be . feeding exclusively on the pulpy fruit of the kahikatea it is not only in very poor condition, but acquires a disagreeable flavour -from the turpentine contained in the seeds. Towards the close of this period, also, the ti-palm (Cordyline australis}, which comes into full bearing only at intervals of three or four years, occasionally supplies this bird with an abundant feast. In May and June it feeds chiefly on the miro and pate (Schefflera digitata), when it reaches its prime and is much sought after. From July to September it lives almost entirely on taraire

(Beilschmiedia tarair in the North, and on hinau (Elaeocarpus dentatus), koeka (Pseudopanax eras si folium), ramarama (Myrtus bullata), and other smaller berries in the South. During the months of October, November, and December it is compelled to subsist in a great measure upon the green leaves of the kowhai (Sophora tetr apt er a} and of several creeping plants. It also feeds on the tender shoots of the puwha (Sonchus oleraceus), a kind of sow-thistle, and the flesh then partakes of the bitterness of that plant. When the bird is feeding wholly on the dark berries of the waowao the colour of its flesh is said to become affected by that of the food. The pigeon season, however, is to some extent contingent on locality ; for example, in the spring of 1863 I found these birds in the upper Manawatu living on -leaves, and so lean in body as to be scarcely worth powder and shot, while in the low-timbered flats under the ranges, where they were feeding on the ripe berries of the karaka (Corynocarpus. laevigata}, they were in excellent condition.” In the above passage the botanical names of the plants mentioned have been inserted, for convenience of references, by .the present writers.* The list of berries is a large one, and may be further increased by the addition of houhou (Nothopanax arboreum), karamu (Coprosma robusta, and C. lucida), and sweetbrier (Rosa eglanteria). Data are lacking as to the proportion of actual viable seed which is passed by the pigeon in eating these various berries. Only the patient observation of years can bridge this hiatus in our knowledge. Although the bulk of the pigeon's food is secured from the' forest, which forms its' chief haunt, it occasionally makes a sally into cleared country. On such occasions the writers have seen it eating shoots of broom (Sarothamnus scoparius), while Guthrie-Smith states: “ They also freely feed on white-clover leaves ; on fallen forest, newly sown, I have known them grow .excessively fat on rape and turnip shaws.” The pigeon is deservedly absolutely protected. THE KIWIS (APTERYX SPP.). There are in the world no more remarkable birds than the kiwis of New Zealand. They are altogether anomalous. For long the systematic omothologist saw in them affinities with that primitive group of birds which includes the ostrich, the emu, and their relatives but the trend of modern research, both anatomical and parasitological, is to place them nearer the rail order. Three species of kiwi, with several races, all confined to New Zealand, are now recognized. If ever birds should be protected solely on account of scientific uniqueness the kiwis deserve that honour; yet they are in considerable danger of extermination by dogs and weasels,' to which their total flightlessness has made them an easy prey. ■ There is probably a strong element of novelty about the suggestion that the kiwi deserves well on any other ground than pure scientific interest. The economic side of the question, especially in view of the popular belief that kiwis live almost entirely on worms, will be found

full of surprises. We have indicated previously, in the second article of this series {Journal, May, 1923), the highly useful role played by the kiwi as a member of the bird police force of the forest-floorthat nursery of silvan insect-life. In this sphere the kiwi is second in efficiency'and utility only to the weka, a bird which has not the kiwi’s clean reputation —with regard to eggs, for example. The kiwi functions firstly as a destroyer of injurious insects, grubs of borer-beetles, and other insects, and secondly as an eater (and probably therefore a dispersing agent) of the fruit of various trees, such fruit being, of course, necessarily picked up from the ground, except when borne on low shrubs. Buller found the stomach of a single North Island kiwi to contain the following assortment : Three large wetas," ten huhus (these are the larvae of our largest beetle, a most destructive . borer, Prionoplus reticularis White), a large longicorn boring-beetle (Coptomma), several earthworms, a large earthworm egg-cocoon, and berries ,of maire {Olea spp.) and of taiko ; {Fusanus. Cunninghamii). The stomach of a second contained unrecognizable . insect-remains,. minute land-shells, and the hard kernel of taiko-berries, which Buller' suggested were used instead of pebbles for triturating the food. .Other kiwis opened had eaten the berries of pokaka {Elaeocarpus Hookerianus), miro, maire, and hinau. In connection with the kiwis,■ one last point needs further stressing. The belief is still prevalent in. North Auckland that the North Island kiwi {Apteryx australis mantelli Bartlett) carries cattle-ticks. Undoubtedly specimens .of these . birds have been caught infested with ticks ; and ticks generally are somewhat similar. The writers have, however, seen hundreds of ticks from kiwis, and in no single case was the cattle-tick ■_ {Haemaphysalis bispino sa Neum.) present; all were specimens of the kiwi-tick {lxodes sp.), which never in any circumstances attacks stock of any description. THE RAILS (RALLIFORMES). Passing over the now uncommon dabchick or little grebe (Poliocephalus rufopectus (Gray)), the. food of which, according to Buller, consists of small mollusca (including probably, the fresh-water snail which acts as a host of the liver-fluke), and leaving its rare and beautiful cousin the crested grebe '{Podiceps. cristatus L.), which is likewise too scarce to be of much economic importance, we come to the large and widespread group of rails. These birds include many highly interesting and insectivorous forms, the smaller of which are so retiring in their habits as to be rarely seen, although much commoner than is usually supposed. Thirteen species have been recorded from the New Zealand region, but several are either rare visitors or stragglers or else confined to the outlying islands, so that there are only seven which- are sufficiently numerous to be of any economic importance. These will be dealt with in turn. The Pukeko (Porphyris melanotus (Temm.) ). This handsome bird follows the rule formulated in another publication by one of the present writers that if we take two related species of New Zealand indigenous birds the one which is the least related to foreign birds will .be the rarer. Thus the birds which have . suffered

most from the adverse influence which our civilization has consciously or unconsciously brought upon them are those which are most peculiarly New Zealand's own. In the present case the pukeko is an abundant species over large portions of the country, while its interesting relative, the takahe (Notornis hochstetteri Meyer), is one of the rarest birds in the world. The pukeko, pukaki, or swamp-hen, with its magnificent blue breast, red beak, forehead, and legs, and black back, is familiar not only to many New-Zealanders but also to dwellers in Australia,. where it is known as the “ red-bill,” a term applied in this country to a totally different bird— oyster-catcher (Haematopus spp.).

The nest is built on a niggerhead {Carex secta) or similar situation, usually in a swampy locality, and may contain a considerable number of eggs not all laid by the same female. . In Australia Cleland and his co-workers found the stomach-contents to consist of vegetable matter, presumably not further recognizable. In New Zealand the pukeko, unless present in large numbers, is a harmless or even beneficial species. Buller states that it. subsists principally on soft vegetable substances, but feeds also on insects and grain. “It frequents the Maori plantations in considerable numbers and proves very destructive to the young crops, and later in the season it plunders the potato-fields and kumara-beds.” But Buller noted also

that this bird often leaves its home in the marshes to travel over the sand-dunes amongst the tauhinu bushes in quest of' grasshoppers.”' The berry of a small Coprosma is also eaten.

Although formerly considered a game bird the pukeko has of recent years been protected, and probably as a consequence of this has in some districts increased allegedly to the' proportions of a pest. One of the writers found these birds tame and plentiful near Whangarei 5 in February, 1923, and was informed that they were a great nuisance treading down oats and . eating the grain. Much of the damage is probably due to trampling rather than to actual eating of the crop. In October, 1923, a paragraph appeared in the Press, at Auckland, to the effect that "complaints which have been repeatedly made by farmers of recent years that the native swamp-bird, the pukeko, did much mischief to growing crops have culminated in the Department of Internal Affairs informing the acclimatization societies that permits might have to be granted to farmers to shoot the birds on their properties. The bird has been protected for some years, and has rapidly increased in some localities. When the matter came before the Auckland Acclimatization Society a report was received from one of the rangers that the birds picked out the young-shooted. seeds from oats, wheat, and other cereal crops, and they also plucked off the thatch of stacks. Members of the council thought that the position might be met by having a general open season for the shooting of the birds in May, June, and July of each year, and it was decided to again suggest to the Department that such open season should be declared/’ Guthrie-Smith, a farmer and a competent observer as well, writes ' On a large run the damage the pukeko can do is trifling. Circumstances, however, alter cases ; perhaps if even I myself possessed but a few acres I should feel annoyance at rape of oats, theft of straw, ravages amongst green maize, wholesale cropping of clover and grass. As man is constituted, the intelligence and high ethical standard of the pukeko may not atone for mischief even on this petty scale/’ The Smaller Rails. . ' Three species of the smaller rails 'occur throughout New Zealand, but all three have suffered considerably at the hand of cats, rats, and probably other ground vermin, and are far less plentiful than they once were. Even in the localities where ‘they are still abundant, however, they- are very rarely seen unless caught and brought home by the domestic cat. The note of the landrail, or pectoral rail, or mohopereru (Hyj)otaenidia philippensis (L.) ), is a piercing scream, often heard at night but not generally recognized by country dwellers. This moderate-sized species occurs in a wider assortment of localities than do either of the very small birds or crakes —the swamp-rail, or putoto (Porzanoidea plumbea (Griff et Pidgeon) ), and the marsh-rail, or koitareki {Zapornia pusilia (Pallas) ), which are practically confined to swamps. All three species are purely beneficial, being almost entirely insectivorous. In the stomach of a landrail Buller found insects, seeds, and the succulent parts of . various grasses. Unfortunately, the ground-frequenting habits and low nesting-places of these rails render them especially liable, as already mentioned, to the attacks of rats, weasels, and other vermin,

and their consequent decrease in the phormium swamps of the Manawatu has probably been a factor in the development of the phormium grubs (Xanthorhoe praefectata Walk, and Mdanchra steropastis Meyr. into pests of importance.

The landrail was one of the species examined by Cleland and his colleagues in New South Wales, which is a portion of the range of this widely distributed bird. He states that this bird appears of some value, as grasshoppers and cutworms have been found in the stomachcontents. Needless to say, these birds are rigidly protected by law throughout the Dominion ; but from the ground vermin which are their chief foes nothing is done to save them. The. Wekas (Galliralius spp.). The wekas, woodhens, or Maori hens, of which we have three distinct species, are large rails, which although possessing ample wings are yet incapable of flight. It is supposed that long isolation in New Zealand,, with an accompanying absence of predaceous mammals. or snakes, rendered flight unnecessary to the ancestors of these birds, and disuse led to atrophy. Their considerable size, coupled with their rich-brown, black-streaked plumage, differing in intensity according to the species, render them easily recognizable. The nest is built on the ground in a variety of situations. GuthrieSmith, who has . made a special study, of wekas, and whom we shall therefore quote considerably, states : “ The whereabouts of the weka’s nest is largely determined by the food-supply of the vicinity, and in spring-time if a beast has got bogged or a fat sheep got trapped in an ‘ under-runner ’ it is quite worth searching for a nest in the neighbourhood. ’ Even after the flesh is no longer fit to eat a great supply of maggots, beetles, and grubs, attracted by the carrion, provide for wekas an ample food-supply.” Discussing further the situation of the nest he says : “ One was on a dry limestone shelf sheltered by a huge projecting peak of the same rock. .' . . Three other nests were built beneath ancient clumps of hill rush and sheltered with a natural ..thatch, of many inches depth and of many years’ accumulation."

Like our other flightless birds, though to a less extent than with the kakapo and the kiwis, the weka has suffered considerably from the influences of colonization. Dogs are its inveterate enemies, in the writer’s' experience rendering impossible the existence of wekas in settled districts, unless dense swamps or impenetrable cover such as gorse thickets are in abundance. So close are the interrelations of nature that we have here, in the case of the gorse, and the wekas, an introduced plant protecting an indigenous bird from the. attack of an introduced mammal.

The food of wekas will be considered in some detail, since in the opinion of all who have given the matter serious study these birds are among the most important economically of all the indigenous birds. In the discussion which follows our remarks will be confined to the common North Island, South Island, and Stewart Island species (Galliralius australis Sparr, and G. hectori Hutton), since the black woodhen (G. brachypterus Lafresn.) inhabits a special locality and exploits a more or less peculiar food-supply. .

The weka functions beneficially, firstly as a destroyer of vermin and insect pests, and secondly indirectly as a-protector of most of the other indigenous land-birds. ' Its crimes lie chiefly in the direction of egg-stealing. It will eat fowls' eggs when it can get them, and, according to evidence quoted by G. M. Thomson, has been a serious obstacle to the establishment in this country of pheasants and wild geese. But W. W. Smith, quoted by Hutton and Drummond, believes that the weka should be held in more esteem, as “ the mere destruction of a few eggs in or near the poultry-yard, or the disturbing of a few pheasants in reserves, may be overlooked when it is remembered that the weka renders inestimable services in destroying vermin.” He goes on to show that the weka eats large numbers of the grass-grub {Odontria spp.), one of the worst enemies of pasture in New Zealand, and states that “ they are also death to rats and mice and help in the destruction of young rabbits.” Similarly, G. M. Thomson writes : Mr. H. B. Flett states that, a good many rabbits which had escaped from captivity at Waitahuna found their way to the open country and increased to a slight extent, but eventually died out completely. He attributes their extermination to the weka or Maori hen (Ocydromus) . . . They used to go into the holes and eat the young rabbits. I have seen a weka killing a -grown rabbit.” So, then, on clear country the weka is an enemy of those two important pests of our grasslands, the grass-grub and the rabbit. Yet it is on just such country that its numbers have been most seriously thinned. Buller found that the weka ate large numbers of berries, worms, grasshoppers, crickets, beetles, mice, full-grown rats, and lizards. Guthrie-Smith writes as follows regarding the food of the Stewart Island weka (Gallir alius australis var. Scotti (Grant)) ■; “ Eggs and young birds of certain species, no doubt, he takes in spring or summer, rats and mice when obtainable, but beetles, grubs and snails, slugs, and roots and berries are provided at all seasons by the forests and open lands, whilst the stony beeches of the inlets and coasts' furnish shellfish and crabs. It is when these ' birds are seen prowling along wet shores, .dislodging stones as large as turnips in their open bills (the weka does not pull them towards him, he moves them entirely by grasp of mandibles) — is then, or when rising to full height, he delivers with his bill a blow worthy of Porthos or Ivanhoe, or when he stands over a bone holding it down with one foot like a dog, and like a dog wrenching from it muscles, meat, and tendons, that you can believe that a weasel might fall before him.”

When we come to the forest country we find the weka playing its second beneficial role, that of an efficient bird-protector, as first described by Guthrie-Smith in the lines quoted below. Guthrie-Smith and many other students of our birds believe that the black rat and the brown introduced into New Zealandare perhaps the most serious enemies of the indigenous birds, and have penetrated , into haunts otherwise untouched by civilization. No nests are safe from their wholesale depredations. -

■ “Itis to such species as the crows, the robins, the tits, the warblers, the thrushes, the saddleback, the bush-creeper, the yellowhead, the whitehead, the wrens, the tui, the bell-bird, the .pigeon, and the parrakeets that the presence of the weka is an unmixed boon. If they

still continue to survive it is to his ceaseless vigilance, his policing of the woods, his eternal patrol of them by day and night, that' we owe their lives ; and these species, we may say, he watches without reward. . From other kinds aided in the struggle for life, such as rails, ducks, pukeko, possibly, and from the fern-bird and ground-lark, certainly he does take fair toll. It is a tribute levied fit and fair, and the merest fraction of what is robbed by rats ;. a mere nominal fee, in fact, charged for life insurance. “ The ' larger kinds of birds, such as kiwis, hawk, falcon, &c., under normal conditions watch their eggs too carefully to give the weka a chance. If in any way his presence in the woods - affects these birds it is to- ensure a high degree of faithful incubation. To them he is a tonic against sloth and carelessness. in our native birds, the most efficient method of preserving the smaller tree-breeding species, lies in the propagation of the weka. ‘ Of all the birds that deserve our care he comes foremost, and assistance withheld from him is help denied to half the indigenous birds of New Zealand." If, then, the present writers have demonstrated in the previous pages of this series the overwhelming proportion of good in the activities of our indigenous birds, they have at the same time proved the economic necessity of efficient protection for the weka. All wekas are protected by law; but an intelligent appreciation by country dwellers of the birds' claims to such protection is also desirable. The black woodhen (G. brachypterus) is ■ largely a shore-frequenting species, found only in the south-west of the South Island and living largely on marine productions, but Philpott has described its behaviour during a plague of mice, which the birds were “ snapping up ” in large numbers. -THE SHORE-BIRDS. The indented coast-line of New Zealand, its numerous lagoons and mud-flats, and the extensive valleys of the large South Island rivers support a large population of shore-birds, Limicolae, or plovers and their allies. They include twenty-nine species, some of them notable the world over for the tremendous journeys they accomplish twice annually on migration. Here we are concerned with themor rather with only a very small proportion of them, since many are very rare, or only accidental visitorsfrom two viewpoints. Firstly, practically all are insectivorous to a certain extent, some . almost wholly . so, while others subsist largely on molluscs (so-called “ shell-fish "). and crustaceans'(shrimps, crayfish, crabs, and their allies) ; and, secondly, they form a source of food-supply which has not yet been developed so extensively in New Zealand as elsewhere. A few common species may be taken as examples. The Godwit (Vetola lapponica (Linn.) ). The godwit, commonly known as “ curlew ” or “ snipe ” (both erroneously), arrives in New Zealand in enormous numbers in spring from its breeding-haunts in Siberia, to which it. returns when our southern summer draws to a close.

In spite of its great abundance, the godwit enters into little actual relation with farming operations. Its food is sought on the mud-flats exposed at low tide on estuaries and inlets. Under the Animals Protection and Game Act this species finds a place in the Third Schedule as native game. The Banded Dotterel (Cirrepidesmus bicinctus (Jard et Selby) ). This plentiful and beautiful- little plover, with its greyish back and black-and-chestnut barred white underparts, is a familiar inhabitant of the beaches and sand-dunes in many parts of New Zealand, and a very frequent visitor to cultivated and pastoral country. On occasion it may even choose a nesting-place on arable land, laying its

beautifully blotched dark-brown and olive eggs in a mere depression of the ground, sheltered perhaps by an overarching leaf of turnip or rape. Few birds are so entirely harmless and at the same time so positively beneficial to agriculture as this little species. The diet is very largely insectivorous.' Like its rarer cousin the other dotterel (Pluviorhynchus obscurus (Gm.) ), the banded dotterel is absolutely protected.

Other Shore-birds. The knot (Canutus canutus (Linn.)), which in the Nelson Province at least (H. Hamilton) shares with the godwit the incorrect title of “snipe,” is another migrant plover, far commoner in New Zealand

during the summer than has hitherto been generally realized. Together with the less plentiful turnstone {Arenavia • intevpres (Linn.)) and the ■eastern golden plover (Pluvialis dominions (Muller)), the knot is placed on the Third Schedule as native game.

The stilts [Himantopus spp.), of which two kinds, a pied and a black, ■occur in New Zealand, are remarkable in that they possess longer legs in proportion to their size than any other bird. The edges of lagoons, the shores of lakes and of the larger rivers, and portions of the coast itself are the haunts of these birds and the source of their food, which consists largely of aquatic or semi-aquatic insects and small molluscs. They are absolutely protected.

The oyster-catchers {Haematopus spp.), sometimes called torea or red-bill, are almost entirely birds of the shore and river-flat. As in the' case of the stilts, one species'is pied and the other black. Their diet consists chiefly of crabs and molluscs, for opening which the long .wedge-shaped bill is especially adapted.- Both species receive permanent protection.

REFERENCES. .Animals Protection and Game Act, 1921 (No. 57). 'Buller, W. L. (1882) : Manual of the Birds of New Zealand. (1887) : A History . of the Birds of New Zealand, 2nd ed. . - ; •Cleland, Maiden, .Froggatt, . Ferguson, and Musson (1918): The Food of Australian Birds. N.S.W. Dept. of Ag. Sci. Bull. 15. ■Guthrie-Smith, H. (1910) : Birds of the Water, Wood, and Waste. Whitcombe and Tombs, Christchurch. ■ (1914) : Mutton Birds and other Birds. Whitcombe and Tombs, Christchurch. (1921) : Tutira —The Story of a New Zealand Sheep-station. Edinburgh; and London, William Blackwood and Sons. ■ Hutton and Drummond (1905) : Animals of New Zealand. Whitcombe and Tombs, Christchurch. ’ . . Myers, J. G. (1923) : The Present’Position of the Endemic Birds of New Zealand. N.Z. Jour. Sci. & Tech., 6, pp. 65—99. • • Philpott, -A. (1919) : Notes ,on the Birds of South-western Otago. Trans. N.Z. 1 .- Inst., 51, p. 216. ' Thomson, G. H. (1922) : The Naturalization of Animals and Plants in New Zealand. Cambridge University Press.

Contagious Mammitis.- —The last annual report of the Department of Agriculture ■states that this disease is still giving considerable trouble in dairy herds throughout -the Dominion, and the advice and assistance of the Department’s officers has been much sought after. Unfortunately, however, before the cases are reported they are, in a large number of instances, in an advanced stage of the disease, and little help can be given. Of 1,051 samples of milk received at the Department’s Veterinary Laboratory during 1922-23 from cases of suspected contagious mammitis, 404, or 38 per cent., proved on examination to be of the contagious •form ; 218 were from cases of the non-contagious type ; and the remainder (429) were normal. Wrong handling of milking-machines is often responsible for setting tip udder troubles, and also for the spread of contagious-mammitis infection. The ■necessity for the exercise of every care cannot be too strongly emphasized. IH h ' Rabbit-proof-fencing District. The constituting of the Te Aria Rabbit-proof-dencing District, South Auckland, has been gazetted.

* We are indebted to Mr. Elsdon Best for the exact identification of several of Buller’s plant-names. Two, however — “waowao” and “whao” —are not known to Mr. Best.