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The native red crabs on Christmas Island stage a mass migration around the end of November.

Forests are usually places of dappled light and muted colours, where the wildlife cleverly camouflages itself. Not so on Christmas Island, a volcanic speck stranded in the Indian Ocean, 2 575km north-west of the Western Australia capital, Perth.

Here, the forest floor is stained crimson thanks to its seething carpet of native red crabs, unique to the island.

During the breeding season, which starts around the end of November, they stage a mass migration from rainforest to ocean. It’s one of the world’s great natural spectacles, once drawing awed admiration from Sir David Attenborough, who called the place “the kingdom of the crabs”.

Apparently up to 120 million of them may live here, and it seemed so when I visited. The large crabs – the island has 20 native species, including the red variety – seemed to be everywhere: on beaches, roads and in the national park that covers two-thirds of this island.

My guide was Lisa Preston, from Island Explorer Holidays. She drove me through the narrow bush tracks to the island’s national park with extreme care but was unable to avoid the occasional casualty. Hearing a crunch beneath her tyres, she let out a wail: “I’m a Cancerian and it strips my heart out every time! “

Our destination was The Dales – a dreamy area of wetland, streams and waterfalls. Lisa led the way through an enchanted forest. Vying for attention were arenga palms, strangler figs and elegant Tahitian chestnuts. Hundreds of crabs scurried among rotting leaves, including the coconut crab, the world’s largest land invertebrate, which can be the size of a small dog.

The former British territory was first spotted on Christmas Day, 1643, by a British sea captain, William Mynors. Australia has controlled the island since 1957. Yet Christmas Island is closer to Java, Indonesia, than to Australia.

Ethnic Chinese and Malays, the descendants of indentured mine workers, make up 85 percent of the population. Buddhist and Taoist temples, scattered around the island, testify to its mixed heritage, as do the noodle shops and trilingual road signs. On the world stage, though, Christmas Island is known as the site of Australia’s main offshore processing centre for asylum-seekers. One camp can accommodate up to 2 000 people, which is more than the island’s permanent population.

This remote spot hit the headlines just over a year ago when a boat carrying Middle Eastern asylum-seekers travelling from Indonesia was shipwrecked, killing up to 50 people. Visitors may well see a navy patrol vessel planted in the main harbour, Flying Fish Cove, or even the latest group of would-be refugees being ferried ashore.

Christmas Island is undergoing a makeover. Since it was settled in the late 19th century, the mainstay of the economy has been phosphate mining. You can still watch phosphate, which is used to make fertiliser, being loaded on to ships via a striking cantilever at Flying Fish Cove. But with reserves dwindling, the islanders need another way to make money. The local tourism authority is promoting the island as a “green” destination, playing on its profusion of endemic species to sell it as “the Galápagos of the Indian Ocean”.

The conventional approach to Christmas Island is a four-hour flight from Perth. Travellers will discover a place of subtle charms. Party animals will be bored, because the nightlife consists of a few low-key bars and restaurants, most of which shut early. Sunbathers should look elsewhere, too: the few available beaches are small and rugged. But it’s the perfect place for twitchers, who flock to Christmas Island from all over the world.

Wandering along a coastal path to a place called Margaret Knoll, we saw golden bosuns and endangered frigate birds soaring on the ocean breezes. The terraced cliffs encircling the island are studded with white dots: colonies of nesting red-footed boobies.

The island is a popular destination for venturing beneath the surface, too, as I discovered on a snorkelling trip in deliciously warm water at West White Beach, a half-hour boat ride from Flying Fish Cove. The marine life – which includes green and purple parrot fish and, in season, whale sharks – is extraordinary.

We spent an hour drifting through a pristine coral garden. “I remember the first time I dived here, I nearly flipped,” says Linda Cash, who runs the local tourism association. “It was so clear, I swear I could see Indonesia.”

Beyond Christmas Island, at least from the perspective of Perth, lies the archipelago with the curious name of the Cocos (Keeling) Islands. This Australian external territory is the place to go if Christmas Island is too lively – and the two are easily combined on a round trip.

Consisting of two atolls, one a wildlife sanctuary, the other a necklace of 26 coral cays, Cocos is a tropical haven, if an eccentric one. Just two of the sunburnt specks of land are inhabited: Home Island is home to 500 or so Cocos Malays whose ancestors worked on the copra plantations; West Island is inhabited by about 130 Europeans. The two are linked by ferry.

Home Island was settled by the Scottish Clunies-Ross family, which established the plantations and brought over the Cocos Malays. West Island was settled separately after World War II, hence the effective segregation. West Island has all the tourism infrastructure; the Cocos Village Bungalows are excellent. A dawn “canoe safari”, led by a resident Australian couple, Ash and Kyle James, explores offshore islands.

For visitors to this quiet backwater, there is sailing, diving, fishing and beachcombing. West Island has one restaurant, one café and one supermarket. The focus of community life is the one pub, the Cocos Club – a tin-roofed building that doubles as the cyclone shelter and as the pint-sized airport’s departure lounge.

Locals include Johnnie Clunies-Ross, a sixth-generation descendant of the original Scottish settlers, who ruled Cocos as a fiefdom for 150 years. Clunies-Ross’s father sold the islands to Australia in 1978; his son – obliged to abandon the family’s ancestral mansion, Oceania House – became a clam farmer and now lives in a modest bungalow.

If you want to hear his story, Johnnie can be found in the Cocos Club most nights. He appears to harbour no bitterness.

“This isn’t the end of my family’s story. It’s just a different chapter, or perhaps a different book. I wouldn’t say I would not enjoy being rich. But you can only drink so much beer, and what else is there to spend money on?” – The Independent.

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