One is a poisonous but striking yellow plant, another an alien snail blamed in part for reducing oyster stocks and a third was once marketed as a prickly aphrodisiac.

One is a poisonous but striking yellow plant, another an alien snail blamed in part for reducing oyster stocks and a third was once marketed as a prickly aphrodisiac.

And you could play a key part in helping work out just how many of each species exists along the Norfolk coast and finding exactly where they are.

For bosses at Norfolk Wildlife Trust have identified five coastal species they want to survey this year and produce distribution maps for each one.

The public have been asked to take a central role in the work as they go about their business of enjoying the beaches and waters from south of Yarmouth to west of King's Lynn.

The five species are:

t Grayling butterfly, which often tilts its wings sideways to avoid casting a shadow. Look for its silver-grey underside with a lighter gray zigzag mark.

t Harbour porpoise, the smallest and probably the commonest cetacean found in the UK, only reaching a maximum of two metres in length.

t Yellow horned-poppy, which has crinkled grey-green leaves often visible all year and extraordinary long, thin, usually curved seedpods up to 25cm long. All parts of this plant are poisonous.

t Slipper limpet, with its oval shell of white, yellow, cream or pink. They live on top of each other forming curved chains of up to 12 individuals. They compete for the same food as oysters but more importantly research suggests they also smother them because of their vast numbers.

t Sea holly, the roots from which were once sold as an aphrodisiac. Look for the very prickly holly-shaped leaves and attractive metallic-purple-blue flowers.

The trust's education manager David North said: 'Our coast is home to some amazing plants and animals, five of which Norfolk Wildlife Trust wants to map the distribution.

'These are sea-holly, grayling butterfly, harbour porpoise and yellow horned-poppy with its beautiful yellow flowers. All are believed to be declining in the county.

'The fifth species in our survey is the slipper limpet, a non-native that is spreading into Norfolk waters. We are appealing to local people and tourists to keep their eyes peeled and contact us with any sightings.'

Trust director Brendan Joyce said: 'If you are at the coast this summer, whether on holiday or just enjoying Norfolk's beautiful countryside, keep an eye out for these five species and get involved in coastal wildlife conservation.

'The survey is really simple to take part in and every record really does count. For help with identification and to learn more about coastal wildlife, come along to one of our special marine events this summer, or visit the trust website.'

The survey runs until the end of October and ties in to a season of coastal events, which include exploring the life in rock pools, walks to Blakeney Point and discovering the nocturnal world of dunes.

The trust is working on the project in partnership with Norfolk Biodiversity Information Service. The project received grants from the Heritage Lottery Fund and European Social Fund.

Survey forms are available from the trust's information service on 01603 598333 or submit sightings online at www.norfolkwildlifetrust.org.uk/naturalconnections.