On a moonlit beach at the Wanan islet off southwest Taiwan, a group of tourists gather patiently to watch a green turtle using her flippers to cover the eggs she has just laid in the sand.
The tourists count themselves lucky as the sea turtles, an endangered species in Taiwan, come to the beaches of several offshore islands for nesting for only a few months each year.
And when dawn breaks a few hours later, they watch as researchers attach a tracking device to the back of one turtle before she slowly makes her way across the beach and vanishes into the ocean.
"It's quite a unique experience to see a huge sea turtle coming ashore to nest. I have never seen an endangered animal before," said Linda Wu, who joined the eco-tour in Wanan, part of some 100 islets of the Penghu archipelago in the Taiwan Strait.
Wu, a secretary from Taipei, has been so impressed by the visit that she is planning to bring her 11-year-old daughter to Penghu next year.
"Eco-tours can provide a good opportunity for children who grow up in the city to learn something about nature and experience outdoor living," she said.
The turtle sighting is the latest of a variety of tours attracting nature-loving, ecology-minded tourists to some of Taiwan's remotest regions.
Such tours boast the island's unique landscape and rare animals with programmes such as trekking across volcanic rocks, watching migratory birds and butterflies, or fishing in lagoons.
In addition to nature, some popular eco-tours feature Taiwan's indigenous cultures, such as a trip to Smangus, a remote mountain village surrounded by cypress forests in northern Hsinchu county and home to the aboriginal Atayal tribe famous for face tattoos and weaving.
"I think there is good potential for eco-tourism because the public are more concerned about the environment and more interested in in-depth travel," said Chen Chih-ming, a guide for an eco-tourism travel agency in southern Kaohsiung.
Chen said his clients, mostly teachers and parents eager to turn holidays into educational experiences for their children, are willing to pay more and put up with less comfort "for a chance to interact with nature".
Still, tour operators say it is painstaking to promote eco-tourism programmes which can be more serious and expensive than regular sightseeing packages.
"I don't think eco-tours can become a mass-market product as some people do prefer singing karaoke at their hotel to midnight turtle-watching," said Quinn Hung, who manages green turtle summer camps on Penghu and Orchid islands.
But Hung, a marine biologist who studied turtles in Hawaii, is hopeful the niche recreation will help raise awareness of conservation.
"Most of our customers are better-educated people who can be a seed to spread the concept of conservation, to pass on what they see and learn to their friends," he said.
The inevitable question remains whether eco-travel would do more harm than good to the environment -- whether more tourists will damage the natural habitats or frighten off wild animals.
Tourism authorities, however, are optimistic the risk will be minimised.
"It is necessary to set a quota on the number of visitors depending on the accommodation and ecological capacity of an area," said Li Chia-shing, of the Taiwan Eco-tourism Association.
"We also encourage visitors to practice conservation in simple ways, such as bringing their own forks and water," he said.