It’s Mexican night at the Irish pub.  Never mind cultural confusion, John Brock, the owner of the Currach Irish Pub in Tryphena, has been milking the concept most of the afternoon, driving through the island’s little towns with three sexy senoritas wearing sombreros and bursting from the popped top of his black, pimped ride – a Hilux work-horse on a normal day.

By eight the pub is honking. A quick headcount around the bar, dining room, verandah and the  overflow in the garden indicates that around a seventh of the island’s population of 750 is here.

The tables are into the second round of Mexican-themed meals – the ceviche is soused with tequila – and bottles of San Miguel slide over the bar as fast as the three senoritas can work the cash register.

Many folk have recklessly cut head-holes in blankets to create ponchos and heaven knows where  all the sombreros come from – the nearest $2 Shop is a four-hour boat ride away in Auckland.

Jarrah, son of the island’s yoga teacher, is walking up and down the verandah steps on his  hands.   His feet are where his head should be and his shirt has fallen down to reveal a glorious set of abs.

By 10pm there is full-on flirting between local lads and visiting lassies amid random garbling of   foreign phrases: “Buenos noches”, “viva l’amour”. Whatever. Language murdering doesn’t matter; it’s part of a Mexican wave of bonhomie so rowdy it drowns the music from the two alternating mariachi CDs.

Finally the revellers sleep. Blue sky melds with sea in wide, shallow Pah Bay and the only thing moving in this soft dawn are the birds. Kaka screech, whistle and warble; they bend flax fronds as they sip nectar from flowers, they flap and play on the edges of pohutukawa trees and others fly high and shout across the sky.

Tui sing melodically, their long and complicated songs ending with a series of the same five notes. They compete with the kaka for nectar and, every now and then, a territorial tui gets aggressive and sends off bigger kaka in a flurry of squawking.

Kereru swish by, then seem to stall midflight, before swooping down in great curves for the sheer pleasure of aeronautical acrobatics.

At the end of the bay a stream spreads and ripples over the  beach to the tide. A family of pateke (brown teal) are busy pushing their beaks around boulders for breakfast. These shy little ducks are all but extinct on the mainland, so it’s a joy to see them living in happy, birdy profusion in the middle of Tryphena, Great Barrier Island’s biggest little town.

Sam and I are up with the birds so we can get to the top of Mt Hobson before the heat sets in. The island is, as kaka fly, only 35km long and half that distance at its widest. Its mountainous topography makes it seem bigger and the steep, winding, gravel roads make driving a few kilometres feel like a longer journey.

In the middle, Mt Hobson’s egg-shaped topknot dominates. At 621m, it’s a modest mountain but, on the west side from Port FitzRoy, it rises pyramid-like from the sea. The easier approach is from the east at Windy Canyon, which is the route we choose.

For the first hour we plod through an ancient volcanic landscape with rocks standing stark and tall, dark drippy chasms, cliffs fluted like organ pipes and razor ridges.

The forest is second-growth indigenous, gnarled and hardy, beaten into submission by wind. This area was extensively logged for kauri between 1925 and 1941 and we pass sturdy weathered derricks that once hauled logs up ridges and swung them over into other valleys.

Senoritas are driven around the island to alert locals

to Mexican night at the Currach Irish Pub.

A bach by the beach at Tryphena.

Kaka, rare on the mainland, abound on Great Barrier.

A no-longer-little shag waits for fish from

mum at Whangaparapara.

 Kaitoke Swamp, with Mt Hobson to the right.

The track steepens and the bush thickens until it’s virgin –   too steep for the loggers – and we notice birds again: fantails, tomtits and families of fluttery grey warblers. There are tui, too, and kereru.

The final 15-minute climb is on smart, new, wooden steps. They’re not, a Department of Conservation sign tells us, built for walkers’ comfort but to protect the burrows of endangered black petrels. These largish (they grow to 46cm long) black birds spend most of their life at sea and come to shore only to nest. And the biggest colony of these birds is on this inhospitable mountain top.

From the top we can see forever: to the Poor Knights Islands in the north; Kawau and Tiritiri Matangi islands to the east; Waiheke is a shadow in the distance, as are the Mercury Islands in the south. Hauturu (Little Barrier) has a collar of wispy cloud and the frilled, convoluted skirts of Great Barrier spread below us with dark bush fingers separating curved, sandy beaches. Going down is the hardest part with Thousands of joint-jarring steps – wooden and rock – to Port FitzRoy.

When we get to the second kauri dam our knees are trembling and we rest. Built in 1925, it has been semi-restored; technically minded Sam tells me how it worked. Kauri logs were felled into the valley below the dams where they waited, for up to two years, for a decent body of water to gather behind the dams. On the designated big day the first dam was tripped, water came thundering down the valley to the second one, which was opened at precisely the right moment, and the force of this raging pent-up torrent took the logs – and everything else in the way – to FitzRoy Harbour.

Port FitzRoy is now a drowsy waterside village with 20 houses tucked into bush, and a wharf where Aucklanders’  ostentatious boats are busy refuelling. There’s a shop, too, and after the six-hour hike Sam and I gobble ice cream and chug down beer. We hitch back to our car, catching a ride with a builder within minutes of standing on the roadside.

The track steepens and the bush thickens until it’s virgin –   too steep for the loggers – and we notice birds again: fantails, tomtits and families of fluttery grey warblers. There are tui, too, and kereru.

The final 15-minute climb is on smart, new, wooden steps. They’re not, a Department of Conservation sign tells us, built for walkers’ comfort but to protect the burrows of endangered black petrels. These largish (they grow to 46cm long) black birds spend most of their life at sea and come to shore only to nest. And the biggest colony of these birds is on this inhospitable mountain top.

From the top we can see forever: to the Poor Knights Islands in the north; Kawau and Tiritiri Matangi islands to the east; Waiheke is a shadow in the distance, as are the Mercury Islands in the south. Hauturu (Little Barrier) has a collar of wispy cloud and the frilled, convoluted skirts of Great Barrier spread below us with dark bush fingers separating curved, sandy beaches. Going down is the hardest part with Thousands of joint-jarring steps – wooden and rock – to Port FitzRoy.

When we get to the second kauri dam our knees are trembling and we rest. Built in 1925, it has been semi-restored; technically minded Sam tells me how it worked. Kauri logs were felled into the valley below the dams where they waited, for up to two years, for a decent body of water to gather behind the dams. On the designated big day the first dam was tripped, water came thundering down the valley to the second one, which was opened at precisely the right moment, and the force of this raging pent-up torrent took the logs – and everything else in the way – to FitzRoy Harbour.

Port FitzRoy is now a drowsy waterside village with 20 houses tucked into bush, and a wharf where Aucklanders’  ostentatious boats are busy refuelling. There’s a shop, too, and after the six-hour hike Sam and I gobble ice cream and chug down beer. We hitch back to our car, catching a ride with a builder within minutes of standing on the roadside.

The rule for the rest of the day is “no more walking” so we go to Harataonga Bay for a lazy late picnic lunch. I remember it as paradise, from my first trip here 25 years ago, and it’s even more beautiful now with the farm fenced off from the beach and the bush grown tall.

The tui and kaka choir is in full chime and pateke paddle in a warm stream behind the beach. The long arc of sand is bright white and we have it to ourselves except for oystercatchers, terns and a pair of dotty little dotterels running frantically, peeping loudly and pretending to have broken wings. They are trying to distract us, not knowing we would never walk above the high-water mark during their nesting season.

Medlands village and beach.

Harataonga Bay, bird heaven and

a quiet paradise for people.

An island 500m from the beach reduces the surf to gentle effervescent waves; the water is cool and refreshing and my overwalked body is in heaven.

Whangaparapara, on the west side of the island, is home base for the night and on the drive there, at Kaitoke Bridge, we stop to pick up two lads aged about 12, hitching a ride. I ask them what they’ve done today.

The more voluble of the pair pipes up: “I got up at 6.30 and went pig hunting with dad. We got a pig but we let it go because it was a sow and she’ll have more pigs later. Then we went home and had breakfast and I mucked around for a while, then this afternoon we went to the beach and went swimming and mucked around.”

Even on the basis of this thin slice of life, a mucking-around summer sounds good for Barrier boys.

We part company outside the Claris Club, alternative watering-hole to the Irish pub, where folk are gathered for a late-afternoon drink or two. Some work the barbecue while herds of children fool around on the sports field below.

The harbour at Whangaparapara is a bush-edged ribbon of sea loved by fishermen and sailors as a haven in all weathers. Great Barrier Lodge, on a grassy knoll a few metres above the water, is an island institution, and its restaurant, bar and little shop are well-patronised by seafaring folk.

A walk around the harbour edge is a nice thought that never happens because we’re both too knackered to move. As the sun goes down, we perch at the picnic table in front of the lodge and watch the watery comings and goings.

There’s a kerfuffle in a nearby pohutukawa tree when a mother shag flies in and two chicks as big as her flap, squawk and shove each other in an effort to get her fish. Mother chooses one and gives it the fish by putting her beak and whole head down its throat in a bizarre snaky action. Then she flies off to hunt again.

Sam spots a pod of porpoises fishing too. There are three gently surfacing, breathing and then sliding under water again. They loll and linger, easing closer to our side of the bay. Sam chinks his beer bottle to my wine glass. This is island-style mucking around perfection.

The SeaLink ferry, a vital connection to the mainland,

causes a flurry when it arrives at Shoal Bay.