Our eyes begin to adjust to the strange light. The sand is an eerie shade of grey and the sea and sky are inky black. It is only 7pm, but already it’s dark and our Jersey Walk Adventures guide points to a daisy anemone that glows brightly in the beam of a UV torch. It may be pitch black, but suddenly there’s a firework display at our feet.

We’re here to see bioluminescence on an unassuming beach in Jersey’s La Rocque Harbour, at the south-east tip of the island. This magical effect is provided by elusive small brown worms. They are rare in most parts of Britain, but you can see them in Jersey all year round, as long as it’s dark and the moon isn’t full. The less light, the better. It helps that there are no street lights close by.

Caulleriella bioculata might not look like much in daylight, but by night, when you turn off your torch, the transformation is dazzling. It’s like stargazing, but instead of looking up to the heavens, it’s in the water and along the shoreline.

The worms are about 4mm long and are easy to miss when they are not emitting their strange greenish glow. When disturbed, they light up and continue to glow for up to 20 seconds before switching off to recharge. The glow is the result of chemi-luminescence, a chemical reaction in their bodies. Scientists still aren’t quite sure why the worms glow, but suspect it is for communication or defence.

As we gently sweep our feet across the ground, the sand transforms into a glorious canvas of constellations. Looking up to the stars, and down to the speckled brightness on the ground is a strange and otherworldly experience.

Derek Hairon and Trudie Hairon-Trox are our guides and both are as enthusiastic as Victorian amateur biologists – the Mary Anning and Alfred Russel Wallace of this stretch of coastline. As we walk, they explain about the vital work of the glowworms, which churn through the sand in the same way that earthworms work the soil, keeping it aerated and soft in texture. British beaches wouldn’t be the same without these hardworking creatures. Trudie and Derek suspect that the worms may be present around much of the British coast – they’ve been reported along the east coast and around north Wales. Here on Jersey, however, thanks to the very low light pollution, they are far easier to see.

The couple were, they believe, the first people to officially identify these glowworms on Jersey. Before their discovery, the creatures were almost unknown to anyone except the local fishermen. Even now, despite Derek and Trudie’s enthusiasm for their find, you will struggle to find anyone on the island who has actually seen the phenomenon.

When I mention the bioluminescence walk (at the hotel, in cabs, even at the local zoo), I’m met with blank stares. This aspect of Jersey’s shoreline seems to be a well-kept secret. Even on an island that’s only five miles wide and nine miles long, where everyone seems to know everyone, nature can still surprise you.

There are plenty of other attractions on the island, too, although be warned that taxis are eye-wateringly expensive and the buses seem to turn up when they feel like it. We stay at the Grand Jersey hotel in St Helier, with views over the mysterious Elizabeth Castle (accessible by ferry or a causeway when the tide is out). It’s a guilty pleasure when it rains because there’s so much to amuse at the hotel with its own private cinema, champagne bar, spa and pool – even more delightful as it comes at such a reasonable price outside the summer season.

I induce serious Instagram-envy on a day trip to St Brelade’s Bay – it’s impossible to take a bad shot (believe me) thanks to its pristine white sand and calm waters. We have lunch at the Oyster Box – fresh catches, a glass of champagne for £7 and excellent people-watching.

For me, the true lure of the island has always been its more exotic side. The Durrell Wildlife Park was established by Gerald Durrell, and I’ve longed to visit ever since reading Menagerie Manor, which is all about his life on Jersey. Designed to act as an ark, protecting and breeding endangered species from around the world, it’s now run by Lee Durrell, Gerry’s widow, who shares his fierce passion for all creatures, no matter how strange (among other treasures, he famously gifted her four tarantulas for their 10th anniversary).

The park is set in pretty, undulating grounds and it’s here that I come face to face with the subject of Durrell’s final book, The Aye-aye and I.

The Aye-aye, a lemur discovered in Madagascar, is the world’s largest nocturnal animals and is related to chimpanzees and apes. Once my eyes adjust to the dark of their nocturnal home, I’m privileged to see one peering out, with its alien-looking eyes, before scurrying into the shadows.

Which just goes to show that several of Jersey’s most fascinating sights can all be found in the darkest spots.

Way to go

Bioluminescence walks cost £15.50 for adults and £8.50 for children; they last 90 minutes (07797 853 033, jerseywalk adventures.co.uk). Durrell Wildlife Park costs £16 for adults and £11.50 children (01534 860 071, durrell.org).

Doubles at the Grand Jersey hotel cost from £107 (01534 722 301, handpickedhotels.co.uk). For more information, visit jersey.com

Correction: the picture of the aye-aye was changed as the original was of a lemur (13 March 2017)