"OH no," wails Lisa Preston, hearing a tell-tale crunch beneath her tyres as she negotiates her jeep along a narrow bush track. "I'm a Cancerian and it strips my heart out every time I kill a crab.
"Sometimes when I close my eyes at night, I see a sea of crabs in front of me."
It's impossible to avoid the occasional casualty on Christmas Island, even when driving as carefully as Preston, a keen environmentalist.
Dubbed the "kingdom of the crabs" by David Attenborough, the British naturalist, the island is seething with them: 20 species in all, including the famous red variety, which stage a spectacular annual migration from the forests to the ocean, and the robber or coconut crab, the world's largest land invertebrate.
It is the crabs, above all, that make beautiful, remote Christmas Island - an Australian external territory 2600 kilometres north-west of Perth - a special place.
Then there are the birds, which draw twitchers from around the globe. The marine life, too, is exceptional; the island - dubbed the Galapagos of the Indian Ocean, thanks to its profusion of endemic species - is a top diving destination.
Lately, of course, Christmas has been in the news for other reasons: the site of Australia's offshore immigration detention centre, it has witnessed a flurry of boat arrivals this year. Visitors should be prepared for such sights as the Navy patrol vessel planted in the main harbour, Flying Fish Cove, but don't let that put you off visiting this wonderful island, whatever you think of Australia's immigration policies.
First spotted on Christmas Day 1643 by a British sea captain, William Mynors, the territory is a place of subtle charms. Party animals will be bored (the nightlife consists of a few low-key bars and restaurants, most of which shut early), and dedicated sunbakers should look elsewhere: the island's few beaches are small and rugged.
But if you love wildlife, and tranquillity, and history, Christmas - a four-hour journey from Perth - is worth the trek, and the flights, now operated by Virgin Blue, have become more affordable.
With the traditional phosphate mining industry on the wane, locals hope Virgin's takeover of the route will boost the fledgling eco-tourism business, regarded by some as crucial to the island's economic future.
Preston, the manager of Island Explorer Holidays, is a great guide. She took us walking in an enchanted forest of arenga palms, strangler figs and elegant Tahitian chestnuts.
Hundreds of crimson crabs scurried among the rotting leaves - a bonus, since I hadn't expected to see them outside the breeding season, when they carpet the roads and beaches. Their migration has been described by Attenborough as one of the world's great natural wonders.
The forest is part of the Dales, a dreamy area of wetlands, streams and waterfalls inside the national park, which covers two-thirds of the island.
Lisa also escorted us along a coastal path to Margaret Knoll, where we saw golden bosuns and rare frigatebirds soaring on the ocean breezes. The terraced cliffs encircling Christmas are studded with white dots: colonies of nesting red-footed boobies.
After a snorkelling trip off West White Beach, a half-hour boat ride from Flying Fish Cove, I understood why the place is a mecca for divers. The water is deliciously warm, the visibility averages 30m, and the marine life - which includes green and purple parrot fish, pale blue long toms and, in season, whale sharks - is extraordinary.
We spent almost an hour drifting through a pristine coral garden. "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."
The island was settled only in the 1890s, after Britain realised it contained rich stores of phosphate. You can still watch phosphate, which is used for fertiliser, being loaded on to ships via a cantilever at Flying Fish Cove.
About 85 per cent of the population is ethnic Chinese or Malay, descended from the 19th century indentured mine workers; Buddhist and Taoist temples scattered around Christmas are testament to its mixed heritage, as are the noodle shops and the signs in three languages.
Virgin's flight between Perth and Christmas Island also takes in the neighbouring Cocos (or Keeling) Islands, so it's convenient to visit the two destinations in the same trip. Cocos - two atolls, one a wildlife sanctuary, the other a necklace of 26 coral cays - is very different from Christmas: far more akin to a conventional tropical haven, although prone to rough weather in cyclone season.
Just two of the sunburnt specks of land are inhabited: Home Island by 500 or so "Cocos Malays", whose ancestors worked on the copra plantations, and West Island by about 130 Europeans.
The two islands, situated on opposite sides of a lagoon, are linked by a ferry, which also travels to unpopulated Direction Island, the site of a World War II battle, now a popular spot for snorkellers and picnickers.
Most activities on Cocos (also an Australian territory) revolve around the water: sailing, diving, fishing, beachcombing, surfing and windsurfing, depending on the season. A dawn canoe safari, led by resident Australian couple Ash and Kyle James, explores several islands, and also features an excellent breakfast, complete with champagne.
You can, though, choose to do nothing on Cocos, or just lie in a hammock and read: it's an exceedingly chilled place.
But don't expect a lot of facilities; on West Island, where tourists stay, there is one restaurant, one cafe and one supermarket, all of which appear to open only sporadically. The focus of community life is the Cocos Club, the lone pub, housed in a tin-roofed building that doubles as the cyclone shelter and also as the departure lounge of the tiny airport.
When we visited, the annual lagoon swim (from Home to West Island) had just been cancelled, for the second time in a week, because of massive swells. However, a celebratory barbecue went ahead at the Cocos Club, where would-be competitors were congratulated on their "intention to participate" and awarded certificates stamped with the word "cancelled".
The locals include John Clunies-Ross, the sixth-generation descendant of a Scottish family that settled Cocos and established the copra plantations, ruling the place like kings for 150 years. John's father, also John, was forced to sell the islands to Australia in 1978; he sank most of the proceeds ($6.25 million) into a shipping line which collapsed in a sea of debt.
The Clunies-Rosses had to give up their ancestral mansion, Oceania House, on Home Island; it is now owned by a former Perth taxi driver.
While John senior went into exile in suburban Perth, John junior - groomed for absolute power and a multi-million-dollar fortune - remained on the islands, where he lives in a modest bungalow and farms giant clams, which he sells to aquariums.
Where to stay:
* On Christmas, stay at the Sunset Bungalows from $100 a night.
* Explore the island and rainforest with Island Explorer Holidays.
* A good dive operator is Christmas Island Diving.
* On Cocos, stay at the Cocos Village Bungalows, $97.50 per person twin share, minimum three-night stay; or Cocos Castaway from $165 a night for a three-night stay.
* Ash and Kyle's canoe safaris run daily.
More information: The Christmas Island Tourism Association has a website at christmas.net.au and the Cocos Islands Tourism Association is at cocos-tourism.cc.
Kathy Marks travelled as guest of Virgin Blue and the Christmas Island Tourism Association.