The tide writes. You collect.

Why the islands shell well

These islands do not collect shells by chance. Under the water, a shallow shelf runs out from the shore. Long-shore currents move shells along that shelf, parallel to the beach. Where the water breaks through between the islands, the passes sort that load and drop it on the same stretches of sand.

Reading the tide

Shells land where moving water slows, so you search on the falling tide and the finding peaks at low water. The hour either side of low is your working window. A tide chart is the only equipment that matters, and low water shows you where the shells have settled.

• The wrack line the last high tide left behind.
• The wet apron of sand that runs just below the wrack line.
• The bars and pass mouths, where the moving current sorts shells by weight.

Shelling at first light

First light makes everything better, because the night's deposit is still unpicked and few walkers are out yet. The low sun rakes across the sand, so every ridge throws a shadow. The serious shellers you pass at seven with full bags did not get lucky. They read the same tide chart you now can.

The winter advantage

Summer visitors shell the gulf, but winter residents harvest it. In the cool months, north winds stir the shelf and throw its shells up onto the beach. The mornings after a blow are the best of the season. Summer still shells fine, but winter shells generously.

Pack a jacket, and keep a thermos in your free hand, because cold-morning shelling is one of the coast's best-kept rituals.

• Whelks the size of a fist.
• Banded tulips.
• Angel wings, on the mornings when the sand feels generous.

Pass beaches and long strands

Each island sorts its own shells along its length. Beaches next to a pass catch the heavy traffic, while long, unbroken strands collect the small and delicate shells. Ten minutes of local advice points your morning better than any app, so ask us or ask at the counter of any fish house.

What you will find

The same shells turn up on these beaches again and again, so learn the dependable cast first. Knowing their names makes the morning's bucket easier to sort, and it helps you spot a rare find when one appears on the sand.

• Lightning whelks, the left-handed whelks.
• Lettered olives, as glossy as a good fountain pen.
• Calico scallops, cockles and pen shells.
• Sand dollars, bleaching white in the wrack line.
• Fighting conchs, which are far gentler than their name.

Banded tulips and murexes reward the patient sheller. The junonia is the coast's lottery ticket, rare enough that whoever finds one will talk about it all through dinner.

The live-shell rule

One rule here is absolute: live shells stay. Before you keep a shell, check that nothing lives inside it, and return anything occupied to the water it came from. The beach refills itself on that courtesy, and the collection you keep is better for being honestly emptied first.

• An olive with its animal still at home inside.
• A sand dollar that still feels like velvet and still moves.
• A whelk with its owner still inside the shell.