Despite all the searching I never did spy a bittern. That was a disappointment because I've never seen one of these big, cleverly camouflaged, endangered birds, though I have heard their booming call.
But during my bittern hunt I did get to see many other rarities, such as an ancient hilltop pa, the flower of the endangered sand daphne and a giant puriri tree with a big hollow full of cave wetas, as well as a host of other birds, many of them also rare. The place we were staying on, an old dairy farm on the coast just north of Whangarei, is now home to 63 bird species, 45 of them native, and 23 under threat.
My guide to these treasures was John Craig, professor of environmental management at the University of Auckland, and in my opinion one of New Zealand's environmental heroes. It was he who came up with the plan to restore the forest cover on Tiritiri Matangi and turn it into an open sanctuary where visitors can see rare species in their natural habitat.
Now John is using his skills to restore this 300ha farm, in Pataua North, bought six years ago by the family-funded Craig Trust.
Exploring the place with him is like a trip back to the future, watching the land reverting to what it was like before the arrival of European settlers.
The wetlands which once covered the coastal flats are being recreated, 160,000 native trees and shrubs have been planted, there's an intensive trapping and poisoning programme to remove pests, and stock has been fenced out of waterways and bush. As a result the birdlife is coming back.
On the biggest of the newly formed lakes waterbirds are thriving. Three kinds of shag, all uncommon, perch on branches round the edge. John points out rarely seen native shovellers and dabchicks. On a beach created by water levels falling due to the drought is a nervous flock of New Zealand's rarest duck, the pateke or brown teal. And there are pukeko everywhere.
The bush, too, is once again echoing with birdsong. As we wander round a loop track through the areas of forest - including some impressive stands of kauri - I notice tui, kereru, grey warbler, fantail, silvereye, pipit, bellbird and an amazing number of kingfishers.
"I have seen a kaka here," says John. "And I know we have kiwi because we found a kiwi egg."
Down on the foreshore, where great surf waves roll into the long, sandy beach, there are lots of seabirds, including the endangered New Zealand dotterel, a variable oystercatcher and a flock of whitefronted terns under the grumpy eye of a blackbacked gull.
John hasn't, unfortunately, been able to bring back the moa but it's clear they were here because he runs his fingers through the sand in the dunes and quickly finds a couple of fragments of moa eggs left behind by early Maori.
Failing a moa, the bird I'd most like to see is the bittern and this is a good place to find them. In the paddocks behind the dunes is a drainage ditch where one regularly dines.
We tiptoe up to the ditch, cameras at the ready. "There he is," says John. "Oh, no, it's only spider webs on the grass."
Fortunately there's another bittern hangout in a paddock across the road. Again we tiptoe up to the drain and this time I have a brief surge of excitement when another damn pukeko emerges from the shadows.
But, by way of consolation, there's a "tut tut" coming from a clump of grass signalling the presence of the very shy fernbird. This is one bird I can imitate so we stand around the grass tut-tutting until, too quickly for us to click our shutters, a fernbird pops out and disappears again.
Never mind, I saw another fernbird during an early morning walk round the property, and this one stayed long enough for me to photograph it. I also got some quite nice photos of a brightly coloured chaffinch perched on a flax bush, a pair of paradise shelduck swimming across waters glowing gold in the early morning sun and pied stilts stalking the shoreline for food.
Clearly the changes being wrought on the property are remarkable but - as the locals are apparently asking while they watch a viable dairy farm slowly disappear - where's the money going to come from?
The plan is to develop develop the farm - now known as Tahi, a name taken from the major pa on the site, O-hua-tahi - into "Australasia's first ecosphere retreat". Two old farm houses have been transformed into luxury accommodation - sites have been marked out for eight more - there's a network of roads, tracks and boardwalks so visitors can explore and, of course, a fabulous surf beach.
The number of guests is increasing steadily, mostly from overseas and often attracted by the retreat's emphasis on sustainable development. That has been boosted by Tahi getting a Qualmark Enviro-Gold rating and being selected by the Zeitz Foundation as one of nine global ecosphere retreats worldwide.
John's partner, Anne Stewart, herself a highly qualified biologist, now runs a small stud based on German warmblood horses, and there are riding trails and three performance arenas. Tahi also makes manuka honey, runs a small avocado orchard and has a surplus of carbon credits it hopes to sell.
It's a great idea but is it working? "Commercially," says John, "not just yet. Let's say we're getting closer to having a positive cash flow."
Jim Eagles was guest of Tahi retreat.