Enjoying the heron now

By PHILIPPA JONES

The square nose of the flat-bottomed boat makes abrupt contact with the bank. Our ecologist guide reaches for a sturdy flax leaf and uses it to tether the boat's railing with a rough half-hitch.

Ian James steps across and tugs a branch of southern rata close so we can admire its exquisite flower. Into the bargain we get a mini-lecture on the interesting and unusual rata family.

This is the new eco-tourism, alive and well in tiny Okarito in South Westland. As a biologist and former consultant in forest ecology to Timberlands, James is a well-qualified guide. His Okarito Boat Tours take small groups out on Okarito Lagoon.

As New Zealand's largest unmodified wetland, the lagoon covers more than 3240ha of shallow open water surrounded by magnificent kahikatea and rimu lowland rainforest. In perfect weather, the Southern Alps can be seen sprawled beyond like a painted backdrop.

It's a haven for nature watchers and a perfect classroom for anyone remotely interested in the environment we live in.

Since James is a sole operator, a trip out on the lagoon with him can be tailored to whatever it is you're interested in. For us today? Well, we're interested in everything. Having spent three weeks exploring the West Coast by car and on foot, to be out here beyond the river delta gives us a new perspective of the rugged coast.

The main attraction, however, is a tiny population of white herons or kotuku (Egretta alba), the only nesting colony in New Zealand. Though they're common in the tropics (where they're known as Great Egrets), New Zealand is near the extreme limits of their range in terms of geography and climate.

The 50 breeding pairs that nest north of the lagoon on the Waitangiroto River are protected by law. The lagoon is their feeding ground.

This morning, James backs the boat down to the water and slides it off the trailer. It's custom-made for his trips, a modification of the kind of river boats used in Australia for crocodile-watching but without the protective bars on the sides.

"You're allowed to put your hands in the water here," James says. "But in Australia the high sides prevent you - you might lose your whole arm!"

Along with a young Israeli backpacker we board and are issued with lifejacket and binoculars. We motor along the channel, chugging along softly at walking pace, and Ian explains that the sandspit, which protects the still waters of the lagoon from the roaring ocean waves, was formed by the vast movement of gravel and sand northwards along the West Coast.

Geology, plate tectonics, Maori history, fish, orchids, not to mention the 70 other species of birds sighted here: we are tapping into James' encyclopaedic knowledge and the more we're interested the more he wants to tell us. White-fronted terns swoop past: "Little ballet dancers, they are," he says affectionately.

As we motor softly up and down the many paths of the Okarito River delta that carry water from the Wahapo and Mapourika lakes down to the lagoon, James scans in every direction for a first sighting of the herons we've particularly come to see. From time to time the boat scrapes the bottom. A lone kayaker paddles by.

All the time the commentary keeps coming. We learn about the salt marshes which are a perfect breeding and feeding ground for wetland species. The marsh is fed by glacial silt: material is ground down by the movement of the glaciers into "rock-flour" and carried by the rivers out to sea where it is kept in suspension by the roaring surf until it's eventually deposited in the lagoon.

As it spreads out over the mudflats it gradually makes them shallower and the plants slowly advance. Okarito is a stronghold for these brave plants, designed to withstand the harsh, twice-daily inundation by sea water alternated with a baking from the sun at low tide.

While salt marshes are fragile and often tampered with for the sake of reclamation and land development - only 10 per cent of New Zealand's original wetlands are still remaining - here in Okarito's estuary they are safe.

And James knows it like the back of his hand. At a likely spot he nudges again into the rushes and cuts the motor so we can identify birds by their song. As we move on to a lesson on kahikatea forest regeneration he stops suddenly: he's seen herons.

Our first impression is one of contrast: how could this majestic white bird be at home in this primeval setting? As it delicately picks its way through mud and shallow water, its elegance is extraordinary.

Indeed its long feathers, beautiful nuptial plumes, were almost the cause of its demise: they were treasured by the early Maori, like those of the huia, and later Europeans almost wiped out the colony in their eagerness to use them as adornment for women's hats.

By 1941 there were only four nests left in the breeding colony and it was declared a reserve. Thus the continued survival of white herons is said to be one of the early successes in wildlife conservation in New Zealand, though they can probably never flourish the way they do in the tropics.

"The colony numbers 150 birds but it's remained that size for the last five years," says James. "I think it's partly because of unreliable food sources - the whitebait season has been poor in the last few years. It may also be environmental extremes. They're very vulnerable to the ferocious southerly storms with heavy rain and when the chicks are at the fluffy down stage they have no insulation if they get saturated to the skin. They die of the cold."

Our heron stands perfectly still. A solitary feeder, it will wait, poised in this way, until a fish or eel comes within striking distance and with a stabbing movement of its articulated neck it will dart for its prey, swallowing it whole.

But it's seen us and it's wary. This is its territory and we are intruders.

Before long it takes to the air, its big wings flapping slowly and purposefully, taking it to another more secluded place. We wouldn't dream of pursuing it further, we're just thrilled to have seen it.

Case notes

* Where

Okarito is a coastal village 20 minutes drive north of Franz Josef.

* When to go

The best time for lagoon trips is always the early morning - trips begin at 8am or 9am. The weather is more reliable on the West Coast after January (the wettest month) through to early winter. Spring can be beautiful but unpredictable. However, there is whitebait to be had then.

* What you will see

The birds that can be seen vary with the seasons. White herons can be seen all year round at Okarito, although many more are present during spring and summer. Waders are present between October and March.

* Cost

A 2 1/2 boat tour with Okarito Boat Tours costs $65 (adults) and $25 (children under 16).

Ph: 0800 524 666

okarito@minidata.co.nz

Westland District Council