Tuesday, 19 February 2008

Wading birds, pebbles and hagstones

Took a trip to the Shoreham beach yesterday with my daughter to collect some pebbles for a coastal display that I will be running for the Brighton Science Festival on Saturday 23rd February. I started at the footbridge, crossing the River Adur. The tide was on its way out and there was a lot of bird activity. Apart from the various gulls, a large flock of grey plover were feeding on a small island of estuary and mussels.

On the mud flats on the far side of the river there were several redshank feeding. Redshark have relatively long legs and stride over the soft mud probbing every now and then with their long beaks. The display will be mainly about the Shoreham Beach Local Nature Reserve and will also be run by the Friends of Shoreham Beach (FoSB).

This is an exciting new nature reserve established in June 2006 and which I have been very pleased to have the opportunity to be involved with both as a member of the management group and as a honary member of FoSB.The beach is comprised of a large shingle spit, formed as the result of several centuries of wave action and westerly deposition of the shingle - Longshore Drift. Above the tide line, where the shingle is stable, is vegetated shingle, a rare habitat for the UK and worldwide. The shingle plants die back during the winter ready for a dramatic transformation in the spring when the plants will burst back into life.

Anyway, more about the shingle. People often this that the shingle is boring but it is infact very interesting. 98% of the pebbles are flint washed into the English Channel at the end of the last ice age or have been left behind as the chalk coast eroded in more recent times.

In amongst the flint are various other pebbles from inland also washed down when the ice thawed. There are also pebbles left over from the large rocks used as ships ballast from the 13th Century until about the 18th Century.

Pebbles with holes, like the one above, are known as hagstones. They were once worn to protect the wearer from witches. They were also tied around the neck of cattle to prevent witches from riding them off to their secret meetings. Large pebbles with holes were tied at the bow of fishing boats to protect them from witchcraft.

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