The sky is full of seabirds, big fat clumsy squawking birds, swooping, diving and clattering – and most of them seem to be coming straight for me.

Thousands of providence petrels nest on top of the 867-metre summit of Mount Gower on Lord Howe Island, which I have just spent about four hours sweating my way up along with 18 other walkers. Our guide summoned the birds with a high-pitched guttural call and down they came, crashing through the forest canopy to see what the noise was about.

Dozens thump to the ground around us with such force, it’s surprising they don’t injure themselves. One walker, with a mild bird phobia, runs off in horror.

Once landed, they rest for a minute, checking us out before they go back to fighting each other. The birds spend most of their lives at sea, so are awkward on land with their webbed feet, and have no fear of humans. Some of our group can’t resist the urge to reach out and pat them.

It’s an exceptional up-close wildlife encounter but Lord Howe Island, about 200km off the mid-north coast of New South Wales, is like that – a huge outdoor natural history museum, with the curated highlights laid out, but where nature still has the power and beauty to shock the senses.

I have come to Lord Howe to take on the Seven Peaks Walk – five days of hiking that traverses the high points of Lord Howe: North Head, Mount Eliza, the hills of Kims and Malabar, Goathouse (half way up Mount Lidgbird), Intermediate Hill and Mount Gower.

Run by Pinetrees, Lord Howe Island’s oldest lodge, the trip up combines a series of day walks, ranging in difficulty from an easy stroll to the challenge of Gower, with wonderful evening meals with your fellow walkers. There are also fishing expeditions, snorkelling trips, reef walks, barbecues, swimming, golf and plenty of other non-walking activities scheduled for the week.

The accommodation at Pinetrees resort.

The Pinetrees accommodation consists of small bungalows, each with its own veranda and en-suite, and a handful of family cottages, all sheltered by towering Norfolk Island pines. There’s a tennis court, gardens, a huge organic vegetable patch and waterfront boat shed where you can grab beer, wine or champagne, all offered on an honesty system. Bike hire is available a short walk down the road.

Pinetrees is run by Dani Rourke and Luke Hanson. Rourke picked me up from the airport on my first day and told me the story of how the couple ended up here. She grew up on Lord Howe, but left the island and worked as a corporate lawyer in Sydney, where she was required to keep track of her working day in one-minute increments to bill clients. They were married in 2006 and they returned to Lord Howe to take over the running of Pinetrees after the death of her mother Pixie Rourke in 2010.

Just don’t let go of the rope and you’ll be fine.

Hanson is an excellent guide. He trained as an agricultural ecologist and we chat about his previous work, field surveys in PNG, local island politics and renewable energy as well as the wildlife and geology of the World Heritage area. On the first two days of walking – to Kim’s Lookout and Malabar Hill (208m) on Monday and Mount Eliza (147m) and North Head on Tuesday – he assesses the fitness levels of our group. Gower is a challenging climb and there’s not much room for error, so he wants to be confident we’re up to it.

The walk to Mount Eliza and North Head takes you out past Old Settlement Beach and North Beach – both beaches face the lagoon and are sheltered, family-friendly swimming and snorkelling spots. These beaches, and others around the island, are set up with barbecues and Pinetrees will pack a picnic hamper if visitors want to spend the day there. Half of the walkers choose to take kayaks across the lagoon and meet the rest of us there.

Walking back to Pinetrees along North Beach.

On the way back from Mount Eliza, we trek over to the Gulch, a shingle beach where we sight turtles and kingfish racing through the water hunting. There are a series of natural swimming holes called the Herring Pools further around the coast, where we have fun jumping in and taking action shots. Even though it’s late May, the sun is fierce and the water warm.

About 10 minutes walk from Pinetrees is Ned’s Beach, the postcard-perfect view of Lord Howe Island. It’s a famous spot for feeding fish – visitors can grab a cup full of pellets and have reef fish of all sorts swim and munch around their legs.

It’s about 20C in the water – Lord Howe is on the edge of the Tasman Sea, right where it meets the Pacific – so warm water currents ensure the sea temperature never dips below about 18C, although I still grab a wetsuit when we go into the water. I put on my snorkel and mask and swim out, diving down to check out the fish that teem across the world’s most southerly coral reef.

The view from north head with the island’s lagoon and Mount Lidgbird and Gower in the distance.

There are more than 500 species of fish in the waters around the island, and it’s easy to recognise about a dozen of the more common ones – the hyper coloured parrotfish, a huge spangled emperor, and doubleheaders that look like grumpy old men. In close, near the shore, delicate corals and anemones dominate; then, as you swim out past the break, the tougher brain corals and fan-type corals replace them.

As well as seeing the reef from below the waterline, when the tide was extremely low, we trekked out over the reef on a day so still that the surface looked like sheets of glass. From the surface, we can see all types of coral and other creatures, including an extravagantly red Spanish dancer nudibranch stranded in a rock pool and an octopus attempting to keep itself submerged as the tide drops .

A spanish dancer nudibranch encountered during a reef walk in Lord Howe Island’s lagoon.

The fourth day of the trip is Gower day. It’s the most difficult of all the peaks except the off-limits 730-metre Mount Lidgbird, so there’s some trepidation. The night before, I stay up chatting and having a few drinks at Pinetrees with the other hikers.

At the bar, a fellow walker tells me the Gower walk is the hardest thing they’d ever done. There’s one part of it known as ‘the get up place’ – a thin ledge where the ocean is about 450 metres below and you need to haul yourself up a cliff face using just a rope. I ask Luke what would happen if you fell at that point: “Would it spell certain death?”

“Well, not straight away,” he replies. “You would hit a ledge first ... and then fall to certain death.”

“Just don’t let go of the rope and you’ll be fine,” he says.

At breakfast the next morning, I tell the other climbers that if I don’t make it back, to tell my family I love them and to pretend I’d been brave in my final moments. All I can think about is my legs turning to jelly, halfway up an overhang with nothing but circling seabirds and distant ocean below.

Goat House Cave, 400m up Mount Lidgbird’s eastern cliff, has views out to Ball’s Pyramid in the distance.

The Rourkes’ children climb the frangipani trees above the breakfast table with the guests’ children (before walking to school in bare feet), reminding me of my own children who I will probably never see again.

We meet Dean Hiscox from Lord Howe Island Environment Tours at the base of the mountain. He is one of only two qualified guides for the Gower climb and knows every part of it.

The first part of the walk takes us along the coast through palm groves and cathedral-like banyan trees for about a kilometre until we reach the goat track, a thin ribbon of a trailalong a cliff face. We’re given helmets to protect us from rock falls and there’s a rope to hang on to. On one side there is a sheer drop down to the sea about 100m below.

Climbing Mount Gower: walkers use ropes to haul themselves up steep sections of track.

A little further on, we reach Erskine Valley, an isolated wilderness of Kentia palms, Tall Mountain palms and tree ferns. We rest here and refill water bottles straight from the creek.

At the ridgeline of Mount Gower, the serious climbing begins with the roped sections. There are about 17 of these sections leading to the infamous “get up place”.

In truth, this isn’t nearly as difficult as I had been led to believe but it still requires some courage to overcome the thoughts of dropping to one’s death. That said, I’m the youngest hiker on the walk. The oldest, at age 70 , doesn’t seem to have too much trouble.

Orchids at the top of mount Gower.

We reach the forest on the high plateau of Mount Gower and the environment changes. Every surface is covered in life – mosses, wood fungus and stunningly beautiful epiphytic orchids with bunches of small white flowers. The island is known for the native Kentia palm of the valley, easily the most successful indoor palm in the world. It spawned an industry of seed collecting that created an income source for islanders for decades. But the palm growing has moved to huge commercial indoor greenhouses, destroying the local industry. Ikea now sell them for $15 a pop.

Up here, the summit is home to one of Australia’s most endangered plants, the little mountain palm. While it’s just as graceful as its popular cousin, it’s hard to cultivate and Lord Howe Island’s rat population mean that the seeds are eaten before they get a chance to reproduce. A plan to cull the rats using aerial baiting is still under consideration, although islanders are deeply divided over its merits.

Pinetrees’ boat shed – walkers have a drink while watching the sunset over the water.

We spend about an hour at the top of Mount Gower, but it’s not long enough. The views are magical, particularly on a rare, clear sunny day. The islands that make up the Lord Howe group rose from the sea through volcanic activity some 6m years ago. Fringing reefs then grew around the volcanoes, later forming the lagoon as the island sunk.

When it’s time to leave the summit and head back down the track, I dawdle at the back of the pack, taking photos, enjoying the solitude – just me and thousands of seabirds hanging there, never wanting to leave the island.

• The writer travelled as a guest of Pinetrees. The Seven Peaks Walk is now part of the 10 Great Walks of Australia, which takes in other famous walks such as the Larapinta Trail in the NT and Cradle Mountain in Tasmania.