A wildlife charity has been hit by an 'appalling' theft that has seen rare caterpillars and plants stolen from an internationally important nature reserve.

Eastern Daily Press: A swallowtail butterfly at Hickling Broad. Picture: David RounceA swallowtail butterfly at Hickling Broad. Picture: David Rounce (Image: Archant)

The swallowtail caterpillars were on up to five milk parsley plants that were stolen from Norfolk Wildlife Trust's Hickling Broad site on the east coast.

Milk Parsley plants are the only foliage the green and black striped caterpillars of Britain's largest butterfly, the swallowtail, eat.

The plants are scarce and the swallowtail is only found in the wild in the fens of the Norfolk Broads.

Police are hunting for those responsible and an appeal has been made by the wildlife trust for anyone with information to come forward.

Eastern Daily Press: Norfolk Wildlife Trust CEO Brendan Joyce at Hickling Broad. 'This is an exceptional response by our supporters to this urgent appeal.' Picture: Nick ButcherNorfolk Wildlife Trust CEO Brendan Joyce at Hickling Broad. 'This is an exceptional response by our supporters to this urgent appeal.' Picture: Nick Butcher (Image: �archant2017)

Brendan Joyce, chief executive of the Norfolk Wildlife Trust, said: 'This is an appalling wildlife crime to dig up these rare plants from an internationally important nature reserve and deliberately take rare swallowtail butterfly caterpillars.

'Britain's vulnerable wildlife faces enough challenges without people callously exploiting precious plants and animals for commercial or personal gain.

'It is very unlikely that the plants or the caterpillars will survive for any significant amount of time away from the reserve.

'The police are investigating the incident and we would urge the public to contact them if they see swallowtail butterflies in an unusual or previously unknown location or if they are approached to purchase any butterflies or plants.'

Milk parsley is listed as vulnerable under the World Conservation Union Red List.

A trust spokesman said: 'Norfolk Wildlife Trust has reported the uprooting and theft of five milk parsley plants from its nature reserve at Hickling Broad.

'Most if not all of the milk parsley plants had rare swallowtail butterfly caterpillars feeding on them and the plants were deliberately removed from the site to acquire the caterpillars.'

Hickling Broad is a Site of Scientific Special Interest and a National Nature Reserve. It is designated as a Special Protection Area under the EU Birds Directive and as a Special Area of Conservation under the EU Habitats Directive.

Anyone with information call Norfolk police on 101.

Swallowtail butterfly facts

Swallowtail butterflies are the country's largest native butterfly and live only on the Norfolk Broads.

Their caterpillars have a unique organ behind their heads, called the osmeterium.

Normally hidden, the osmeterium can be used when the caterpillar is threatened to emit smelly secretions containing terpenes.

The adults are often tailed like the forked tail of some swallows, giving the insect its name.

As a butterfly it prefers areas of mixed fen usually dominated by sedge, or sometimes reed, which are cut periodically and contain tall, prominent food plants.

The Butterfly Conservation organisation describes swallowtails as 'one of our rarest and most spectacular butterflies'.

During the 20th century fenland management ceased and much of the butterfly's habitat was lost.

Today active management of the fenland plays an important part in the survival of the swallowtail in Norfolk.

Hickling Broad

Hickling Broad is on the Upper Thurne river system and plays host to a significant percentage of the UK population of common crane.

Bitterns, marsh harriers, bearded tits and Cetti's warblers, barn owls and kingfishers can be spotted on the reserve.

Mammals that call it home include Chinese water deer, red deer and otters.

As well as swallowtail butterflies, the land is also home to the Norfolk hawker dragonfly.

In April the Norfolk Wildlife Trust raised £1m in an appeal to buy the 655-acre Hickling Broad estate.

That purchase meant Norfolk Wildlife Trust owned 1,400 acres at Hickling Broad, about 60pc of the total area in one of the most wildlife-rich wetlands in the UK.

It regularly attracts visitor numbers of 10-12,000 a year.

Prince Charles lent his support to the £1m Hickling appeal in a rallying call to members as the appeal reached its climax.