Jim Eagles enjoys the company of the rare birds that thrive on Tiritiri Matangi Island.

Gnarly old Greg, the oldest takahe on Tiritiri Matangi, turned 18 on Saturday, but the festivities probably won't be chirpy as far as he's concerned.

For one thing, Greg's long-time mate, Cheesecake, has just run off and had two chicks with a hunky newcomer called Te Mingi, so he's feeling a bit lonely.

For another, the volunteer guides who show visitors round Tiri (in return for a $5 donation) will be enjoying birthday cake and other goodies every day this week to mark the occasion, but Greg won't be allowed to join in because as much as he might enjoy human food it isn't actually good for him.

And those killjoy volunteers aren't keen on the way the old fellow has sought consolation by nicking food from unwary picnickers or becoming affectionate towards the occasional visitor wearing blue jeans - probably because they're about the same colour as Cheesecake - and they've set up a special roster of Greg monitors to try to stop him having fun ... or getting into trouble, as the guides see it.

So it was no great surprise that when I bumped into Greg on Tiri last week he was stomping out the door of the visitor centre with a face like thunder.

We had just unpacked our lunch after a truly fantastic walk through the bush of this wonderful island sanctuary and I had a brief panic that he might jump up on to the table and pinch one of my sausage rolls.

But, fortunately, Greg seemed to be thirsty rather than hungry because he charged past our table and headed straight for his paddling pool - the one right under the sign saying "Do not feed the birds" - where he had a drink and a bit of a splash around.

That seemed to cheer him up because he posed agreeably enough for a few young fans - understandably keen to get get photos of a bird once thought to be extinct and even now officially endangered - then strolled off towards the old Tiri lighthouse in the hope of finding someone with a spare ham sandwich lying round.

The takahe are certainly one of the great attractions on Tiri - after all, where else in the world can you get your lunch stolen by a supposedly extinct bird? - but even with Greg on patrol and the other takahe off raising their chicks there was still plenty to see.

It's amazing to think that just 25 years ago this place was mostly bare farmland and, now, thanks to the volunteers who have planted more than 250,000 trees, it is covered in forest and alive with birds, many of them, like Greg, rare or endangered.

As if to underline the point, as we sat munching our sausage rolls a fine fat kereru perched on a treetop behind us, several hihi (stitchbirds) and whiteheads flittered through the leaves looking for insects and a chorus of bellbirds provided background music.

It had been like that all day, really, with birds popping up everywhere. Our ferry was still pulling into the wharf at the end of the 80 minute cruise from Auckland (via Gulf Harbour) when we spotted a kingfisher perched on a flax bush and a pied oystercatcher nesting on the rocks.

And we had no sooner landed and been introduced to our volunteer guide, Donald Snook, than he was pointing out a whitehead nest in the wharf shed, a couple of kereru resting in a nearby tree, a saddleback calling from just up the road and what he called "the rare orange-crowned tui" - a tui with its face covered with orange pollen - feeding greedily on the flax flowers.

As we wandered down the track from the wharf to Hobbs Beach there were two more such rarities: orange-crowned saddlebacks and bellbirds, all taking full advantage of the fact that the flax were in full bloom.

Their refined nectar sipping was in sharp contrast to those of a small flock of kakariki who, their beaks not having evolved to fit inside the flowers, simply ate the blossoms whole.

There were even more birds on display when we came to a huge old pohutukawa tree which was covered in crimson flowers.

Bellbirds, saddlebacks and kakariki were all feasting on the nectar of the flowers and suddenly a swirl of wings announced the arrival at the banquet of two kokako, identified by Donald as Te Rae and Chatters.

They were an amazing spectacle, climbing round the tree on their long legs, looking almost clownish but actually amazingly sure-footed, their blue-grey plumage and bright-blue wattles standing out vividly against the red of the flowers, their heads constantly disappearing as they tucked into the nectar.

We watched, entranced, and even Donald, a Tiri veteran, was astounded. "I've made over 300 trips to the island," he said, "but it's the first time I've seen that. Amazing."

When I've visited Tiri previously, the sugar-water feeding stations dotted through the bush have been the best places to see birds but this time they were deserted.

"Usually the feeding stations are the highlight," agreed Donald. "But who wants Chelsea sugar when you can have pohutukawa nectar?" Of course as soon as he said this a flighty hihi, resplendent in its Taranaki colours of yellow, black and white, popped down to the feeding station beside us for a drink.

But Tiri hadn't finished with its surprises. As we walked into one of the few remnants of the island's original forest cover, I noticed bits of wood and bark falling from high up in a tree alongside the path.

"That's strange," I said to Donald. "That's what you'd expect from a kaka. But you don't have kaka on Tiri, do you?"

Donald didn't answer and a few moments later a large brown parrot fluttered down, landed on a branch and started enthusiastically tearing at the bark with its powerful curved beak.

"I didn't mention it, because I don't like to disappoint people," said Donald with a grin, "but there have been a couple of kaka hanging around for the last two to three weeks. We're hoping they might stay and nest."

It's surely the ultimate tribute to those who transformed this island into a wildlife sanctuary that a bird that is listed as nationally endangered, the North Island kaka, should make its own way there for a holiday and maybe to live.

Further into the old bush, we watched three North Island robins bouncing along the forest floor, spotted a couple more kereru chilling out on high and applauded as several tui engaged in a noisy battle for supremacy.

About the only thing I didn't see was the rifleman, New Zealand's smallest bird, 31 of which were introduced from Little Barrier last year. They've apparently settled in well but, despite checking out a couple of their nesting boxes, we saw no sign of them.

"Ah well," said Donald. "The ranger saw one in the workshop the other day inspecting the tractor engine.

"Perhaps they prefer nesting on a John Deere to the nesting boxes we built." I thought of checking the tractor out but when we got to the workshop the tractor shed was locked. Pity.

Instead, just as we got to the visitor centre there was one final delight: a couple of neat brown quail. Surely these couldn't be the New Zealand quail, thought to have become extinct about 160 years ago?

"No," said Donald. "There was at one stage a hope that might be the case. They did some DNA tests to check and found they're actually Tasmania quail, probably brought here by one of the early lighthouse keepers.

"But from what we know from the drawings of the New Zealand quail, they are pretty much identical ... so these are the next best thing." It was worth a try.

If the extinct New Zealand quail were going to be found anywhere it would have to be on Tiri, playing with grumpy Greg.

Further information: 360-Discovery cruises visit several Hauraki Gulf islands including Motuihe, Rangitoto and Tiritiri Matangi.

Fullers will be running a series of special cruises to explore rarely visited parts of the Hauraki Gulf in late January. These will include cruises around Little Barrier, Great Barrier and the Noises, guided walks on Rotoroa, Kawau, Motuihe and Motutapu islands, and a walk around historic Coromandel town.

To find out more about the Tititiri Matangi project visit tiritirimatangi.org.nz.

Jim Eagles visited Tiritiri Matangi as guest of 360-Discovery and the Supporters of Tiritiri Matangi.