MIRANDA Learning about our coastal heritage

Forest and Bird, Volume 19, Issue 3, 1 August 1988, Page 18

MIRANDA Learning about our coastal heritage

The western shores of the Firth of Thames are internationally recognised for their abundant wading and migratory birds. The Miranda Naturalists’ Trust, formed in 1973, is proposing to build an Education Centre near Miranda in time for the 1990 International Ornithological Congress. Well known ornithologist R.B. Sibson describes the high natural values of the Miranda coast. Ae the New Zealand coast from arengarenga Harbour in the far north to Paterson Inlet in Stewart Island, there are several large coastal inlets with broad intertidal flats of mud, sand and shell, extensive areas of saltmarsh and networks of creeks and runnels. Every year these rich feeding grounds support flocks of shags, herons, gulls and terns; and especially the strong-winged, far flying migratory waders. This diverse and enterprising clan may be divided for our purposes into two groups. There are those which breed in New Zealand: for example, wrybill, dotterel, stilt and oystercatcher. These, when nesting is over, form flocks and migrate internally, for movement is an essential part of survival, although a few local populations are more or less sedentary.

And, there are those sub-Arctic breeders which come from northern Asia or northwest America to avoid the boreal winter and to spend a southern summer in a temperate climate. Sir Walter Buller’s five volumes on the history of New Zealand birds have little to say about the Firth of Thames, which is not surprising since in the nineteenth century most communication between Auckland and Thames was by ship; and the western and southern shores were backed by almost impenetrable swamp forests and the larger rivers were unbridged. However, in his Supplement (1905), Buller graphically wrote of the wrybill "In the summer of 1895 I received a large number of specimens from Captain Mair who shot them on the extensive flats at the mouth of the Piako River’. And another significant reference concerns sharp-tailed sandpipers of which he had received ‘‘some beautiful specimens"’ from the same river mouth. Food and security Now some ninety years after those first reports, how satisfying it is to be able to claim confidently that the Firth of Thames and the Miranda coast still afford ample food and security for these two small migratory species, one an endemic plover and the other a trans-equatorial sandpiper. Indeed they may be considered symbolic of the wader population of the Firth’s muddy foreshore although they are by no means its most numerous inhabitants. We now know that the Firth is both a terminus and a staging post for tens of thousands of long-distance migrants. But its real value and importance were not discovered until the mid- 1940s when a small group of local Nola: (aaah to pay it

regular visits. They did this in order to study the breeding of stilts and dotterels, to count the numbers of godwit, knot and oystercatcher and the rarer waders, as they all varied seasonally, and to investigate their feeding habits and movements in response to the rise and fall of tides. As the number of concerned naturalists increased, the Firth of Thames became a name to conjure with. Study groups from the Forest and Bird Protection Society (not yet Royal) planned excursions. In February 1949 on a tour organised by the Pacific Science Congress and led by local ‘experts’, ornithologists from many countries were able to see birds which they had never seen before. For the bird-watcher, the Miranda coast has earned a reputation for both quantity and quality and such was the interest that it was possible to organise bird censuses, which would take place twice a year as near as possible to June 21st and December 21st, when tides were suitable. At such times of the year migrational activity was at a minimum because the flocks would have settled into the routines dictated by midwinter and midsummer. The most impressive numbers, though,were most likely to be present in Feburary and March. It may be risky to deduce too much from one year's figures, for even a sizeable flock can escape notice in the wide open spaces of the Firth; but when the figures for thirty years are carefully scrutinised, they can gain real significance. Long-distance travellers In the last half centugy much has been written on the birds of the Firth of Thamés fot only in Notornis (the magazine of the Orni-

thological Society of New Zealand) but also in other scientific publications. One of its claims to distinction is that from its shores come the first records in New Zealand of some long distance travellers, namely Asiatic black-tailed godwit, grey and ringed plover, Mongolian dotterel, Terek and broad-billed sandpiper. Among its thousands of what are termed its normal or common species, are usually one or two of exceptional rarity, recent examples of which are Asiatic dowitcher and marsh sandpiper. Naturalists who visit the Firth have good reason to travel in hope. In 1974 the Miranda Naturalists’ Trust was founded by a group of enthusiasts who, backed by many years of experience, were convinced that the west coast of the Firth was an ideal place fora pefmanent observatory, as a base from which others, young andegld, could learn, Something of the won-

ders of our natural coastal heritage. Also of the mysteries of that remarkable phenomenon, bird migration. The annual reports of the Trust contain much detailed information, not only about birds but also about the local botany and invertebrates, especially cicadas. Geography and climate have given the Firth special advantages since frosts are seldom severe. Its shores are therefore all the more attractive to the great flocks of wintering waders. Here, too, the sub-tropical mangrove nears its southern limit. Over the last thirty years the remarkable growth of mangroves may point to an amelioration of the climate. For the birds of the exposed flats, these mangroves now offer shelter against the biting southerlies which from time to time blow down the Hauraki Plains. As the Firth widens northwards to the Hauraki Gulf the many islands of the Approaches support colonies of gannets, terns and shags, including the spotted shag, a southern species here near the northern limit of its range. Over these outer waters, as the seasons come and go, shearwaters and petrels forage with the gannets, shags and little blue penguins and may penetrate far up the Firth when fishing is good. The lowlands of the Firth still hold plants which have become raregglSewhere. On the "west thé/high forested slopes of oo OS five and on the east Fy Coromandel Pe insula, still offer rugged tracts, . spite possums and other atien br@w; mpuxtaas of northern and southern p ants Vay

should delight the heart of any perceptive botanist. Over the millenia, geography and climate have treated the Firth of Thames so generously that it offers unlimited scope for research to naturalists of all disciplines. In all its moods it is artist's country too. Those who have eyes to see and search and persevere seldom come away disappointed. All things in Nature’s vast store must be treated on their merits. For example, sharptailed sandpiper, pectoral sandpiper and curlew sandpiper clearly have much in

common as well as size and general shape. Yet, as years of study have shown, they differ in many ways and their life-patterns are quite distinct. And in New Zealand their diet, a very difficult subject for research, has hardly been investigated. In New Zealand's long archipelago there are few better places to learn about our immensely rich and varied coastal heritage than in the Firth of Thames. y& The Miranda Naturalists’ Trust needs to raise $500,000 towards the cost of the Education Centre project. If members would like to help, write to The Secretary, Miranda Naturalists’ Trust, PO Box 39-180, Auckland West.

Counts of Selected Species from Winter and Summer Censuses Firth of Thames 1978

Endemic Waders South Island pied oystercatcher Banded dotterel Wrybill Pied stilt Migrants Golden plover Far eastern curlew Whimbrel Bar-tailed godwit Turnstone Lesser knot Sharp-tailed sandpiper Curlew sandpiper Red-necked stint Winter 12,091 78 2,011 5,918 256 52 900 Summer 1,131 190 1,101 150 12 21 5,292 141 7,472 23 20