When biology undergraduate David Tan got a call telling him that a sea turtle had been spotted at East Coast Park, he found himself wrestling with two conflicting impulses.
While he wanted a rare glimpse of the endangered creature laying its eggs, he was also wary of disturbing it.
"Excitement got the better of me," said the 24-year-old. After hearing of the sighting from a friend earlier this month, he headed straight to the spot, near East Coast Lagoon Food Centre.
When he arrived after midnight, the keen naturalist saw the creature being watched from a safe distance by several other people, most of whom were National Parks Board (NParks) staff.
The turtle - believed to be a hawksbill - heaved itself back into the sea about an hour later, without laying any eggs. But Mr Tan managed to take a photograph, without using a camera flash to avoid disturbing it. He said it had chosen a "weird spot" to nest, adding: "The sand is compacted and it's quite grassy."
NParks National Biodiversity Centre director Lena Chan said it had been notified of the nesting sea turtle at 11.25pm on July 21. It was the first reported sighting at the beach this year.
Sea turtles sometimes abandon their attempts to lay eggs if the ground is not suitable or if they are disturbed, said Dr Diong Cheong Hoong, 66. The creatures are generally spotted nesting in Singapore once or twice a year, added the retired National Institute of Education biologist.
Marine turtles have long flippers and are adapted to life at sea, returning to shore only to lay eggs. There are several species, with hawksbills and green turtles the two most commonly sighted here. Only the hawksbill has been recorded laying eggs on Singapore shores, perhaps because green turtles are more picky about nesting sites or more sensitive to light.
Both species are critically endangered. They have been losing their habitat to humans, who also harvest their eggs and meat.
Dr Diong said isolated areas such as Semakau should be set aside for hawksbills to nest.
"With fewer natural beaches, and beaches gradually being settled, it's dismal for turtles around the world," he added.
Members of the public who spot a turtle nesting should move away to avoid distracting it and call the police. Officers will then cordon off the area to protect the nest from poachers and animals.
Those who spot turtles or their eggs on Singapore beaches can also call the 24-hour NParks helpline on 1800-471-7300.