Author: By M. R. Montgomery, Globe Staff

Date: SUNDAY, February 21, 1999

Page: M18

Section: Travel

These southern lands had no native land mammals. Human intervention has brought a plague of four-footed things. Bambi and his cousins are among the most destructive. Introduced European red deer are such pests that there is no closed season and no limit on how many red deer a hunter can take. Rats and cats, ferrets and weasels, even the intensely cute Australian possum -- all have changed the landscape by chewing on the native plants and animals.

Generally speaking, aptly named South Island is more ``natural'' than North Island. But to get close to how things really were, visitors with a taste for natural history will go a little farther south.

Even closer to the Antarctic than South Island lies an archipelago consisting of a single inhabited isle, Stewart Island, and a scattering of seldom-visited and lonely islets. Of these, for many reasons, little Ulva Island is the best-known secret place, served by water taxi and crisscrossed by walking trails sensitively sited by the national Department of Conservation.

Yes, you could get there on your own, but that would be a serious error. After all, Americans have come halfway around the world in both directions -- east/west and north/south -- and no matter how many field guides we read and carry, there is no substitute for local knowlege. Even travelers who have already toured the temperate rain forests of South Island will be out of their element on Ulva. Fortunate is the visitor who is introduced to Ron Tindal, a retired Department of Conservation officer who can take some credit for the uniqueness of Ulva Island and who, for a very reasonable fee (some $25 US, including the water-taxi fare) will show you a dozen or a hundred (depending on how well you pay attention) things that would otherwise escape your eyes.

The uniqueness of Ulva Island is not in its vegetation or its bird life as such but in the incredible richness of both. The original owner of the island, Charles Traill, was an amateur and enthusiastic naturalist who recognized long before most New Zealanders that introducing foreign animals was a great mistake. He kept deer off the island, and rabbits as well. Ferrets and weasels, both introduced to try to cut down the rabbit population in most of New Zealand, never made it to Ulva.

The remarkably destructive Australian opossum was introduced to New Zealand in the late 1920s. It is a nectar and pollen eater, putting it in direct competition with almost all of New Zealand's land birds. When someone asked Roy Traill, Charles's nephew and second owner of the island, what he would do if someone put possums on Ulva, he replied:

``First I would shoot the person who brought the possums. Then I would shoot the possums.''k

The only alien animals on Ulva were rats and mice, including the Norway ship rat, the common house mouse, and the Polynesian rat, introduced deliberately by the Maoris, who ate them with gusto. Beginning in the early 1990s, the Department of Conservation undertook a serious program to remove the rodents and return Ulva to a pristine past unequaled in any New Zealand reservation open to the public.

Tindal, at 70, with the fine shock of white hair that implies a vigorous outdoor life, remarked to a slightly younger traveler: ``Perhaps you are of an age to remember the old military term `rolling barrage.'

``That is what was done here, rather than trying to poison the entire island at once, they began at one end with successive `barrages' of poison across the width of the island.''

As he led a trio of tourists through the woods (``bush'' in New Zealand-speak), he pointed out the occasional pieces of bright yellow plastic tubing near the footpath. These were monitoring stations and poison dispensaries in case a rodent should reappear, most likely from a visiting boat. ``This being New Zealand,'' Tindal offered with a grin, ``naturally we use butter as a monitor. It works quite well, the natural diet is low in fat, so butter is attractive, and we can tell by the teeth marks whether it has been visited by a mouse or a rat, or just nibbled at by one of the local birds.''

The forest floor on the island was the first clue that visitors had entered a renewed primeval landscape. Along the path, for the first time in New Zealand, the ground was sprinkled with the just-ripened fruits of the trees high above. Elsewhere, either the possums had gotten to the flowers first or the scavenging mice and rats had gleaned every nutritious bit from the leaf litter.

The second clue was the sheer abundance of birds. On South Island, it is true, there were bell birds and tuis, the former an inconspicuous green bird heard more than seen and the latter a striking black bird the size of a robin and decorated with white plumes on its neck like a tuxedo-wearing diner who has decided to tuck a linen napkin into his shirt front. On the big island, a tui was a bird to be remarked upon.

On Ulva, the inquisitive tuis amounted almost to a nuisance, they all wanted to approach the visitors and announce their interest and defend their territory with a peculilar loud wingbeat combined with melodious, but noisy, whistling. Bell birds were so frequently encountered that one could count on seeing a bird, not every one would be nestled in amid camouflaging green foliage.

The largest land bird on Stewart Island and its smaller neighbors, a green and rusty-red parrot, the Kaka, was nesting and feeding young wherever we walked. They too announced their presence and our arrival with a bellicose and unmusical screech. As we entered their territory, one of the adults would fly close, clearly interested in keeping an eye on the large and curious visitors. We watched one fly up to us, land in a tree over our heads, and then begin to preen itself. A visitor remarked to Tindal that the bird seemed calm enough to stop calling, and start arranging its feathers.

``Probably not,'' Tindal said quietly. ``That bird's actually quite nervous. The preening is a displacement behavior. They are just like people in that respect. Perhaps you have noticed that an uneasy public speaker will run his fingers through his hair when called upon, or touch up her face or eyebrow with a finger, before talking.''

In a half-hour, we had seen two of New Zealand's three native parakeets (the third was not to be expected in any case), been shown kiwi tracks in a muddy spot on the trail, and been visited by a flock of birds so uncommon that lifelong residents of South Island had never seen one. This last bird was the New Zealand brown creeper, about the size of, and with many of the habits of, a North American chickadee. They were two-tone brown, the body a sort of milk chocolate, and the head a really striking chestnut, almost auburn colored in the right light. They came in little waves of 10 and 20 birds, mewing to each other and passing over and beside us, just parting to get around our human obstacle, as they foraged on trees and ferns for the small insects that make up most of their diet. Winter walkers in North America will remember chickadees moving so sociably through the woods.

One occasionally visits woodlands with naturalists who announce things like: ``There are more than 20 kinds of ferns native here.'' Tindal knew the names of several dozen ferns and tree ferns, he could offhandedly identify the mosses, lichens, and such obscure families as the liverworts and spleenworts. ``Spleenworts,'' he remarked casually, ``are rather interesting because they hybridize so easily.'' He then pointed out several hybrids, a level of knowlege not commonly encountered in the company of ``experts.''

Too soon, it was time to get back to Post Office Bay and catch the water taxi to Stewart Island. Tindal was asked whether he thought someone else would take up his style of guiding someday when he was retired again from this second career. He thought not. ``People specialize too soon now,'' he said. ``They just do not have the same general knowlege as the older generation.'' He said it uncritically; it was just another keen observation of the natural world. ``By the way,'' he added, ``if you have time some day, you might like to go along on one of our marine trips. We do all the seabirds and penguins and stop and pull a few rocks and do all the intertidal zone stuff.''

Probably, one imagined, including the hybrids.

Tindal, should you want an answer for everything you ever wanted to know about the ecology of New Zealand's finest temperate rain forest, can be reached at PO Box 109, Halfmoon Bay, Stewart Island (no postal code needed). His telephone for both voice and facsimile is, after reaching your international carrier: 64 (New Zealand) 3 219 1453.