Captive-bred crickets released into the wild

NOT OUT FOR A CENTURY
London Zoo-bred animals a singing success on the cricket field!

On Wednesday 30 August the Zoological Society of London (ZSL), of which London Zoo is an integral part, will be involved in a further animal release to the wild. Two thousand captive-bred British field crickets (Gryllus campestris) will be released in the Hampshire County Council nature reserves Broxhead Common and Shortheath Common. This is likely to be first time they will have been heard singing in these areas for over a century.

Following previous releases of captive-bred British field crickets into the countryside, a number of colonies are successfully establishing themselves. In the first release of this species this year, London Zoo will provide two new re-introduction sites (Broxhead and Shortheath) with about 1,000 crickets each, whilst releases to three other sites will occur later. Eggs produced from three pairs of wild caught crickets were nurtured to provide crickets for these sites by keeping staff at the Web of Life, London Zoo’s biodiversity centre.

"The Web of Life team here at London Zoo are delighted to continue to re-introduce captive-bred British field crickets into the wild" comments Dave Clarke, Head Keeper of the Web of Life at London Zoo. "It is great to show that all species, including British field crickets, are important. Few people know that the population was down to less than one hundred individuals in the 1980s and we are proving once again the importance of the role of captive breeding for re-introduction andthat we can bring them back to the British countryside."

In 1991 it was estimated that, without action, these indigenous insects of Britain would have died out within six years. The species was included on the English Nature Species Recovery Programme by Dr David Sheppard, an Inverebrate Ecologist for English Nature, with the aim of creating six new colonies in sites around Southern England. London Zoo’s Web of Life team has worked hard with English Nature to find suitable sites and this year Broxhead Common and Shortheath Common have been chosen and are thought to be ideal by Hampshire County Council. Both are Sites of Special Scientific Interest (SSSI) and have been chosen as they have the ideal conditions for the crickets to thrive. Rangers at the reserves have cleared bracken and stripped turf to help provide the perfect habitat.

The Zoological Society of London has conducted thorough testing of the British field crickets to ensure that all the individuals are healthy when they are released. This is an essential process when re-introducing captive-bred animals to their natural habitat, as it reduces the risk of introducing diseases that could threaten resident populations. ZSL is also involved in vital investigations to identify the amount of remaining genetic variation in the British populations of field crickets compared with continental populations.

"This is yet another important step in one of London Zoo’s conservation programmes and also the wonderful on-show breeding facilities in the Web of Life," adds Dave Clarke. "British field crickets are a great example of global biodiversity and of the variety of life we can find in our own countryside. It’s great to be re-introducing them to the wild -- a real conservation success story for the Zoological Society of London."

ZSL has been involved in a number of release programmes this year. In June, wart-biter crickets were released in West Sussex and in early July, ZSL’s veterinary staff were involved in a red kite release. As well as these projects, ZSL is involved in on-going reintroduction programmes abroad, including a ruffed lemur project in Madagascar, Arabian oryx and sand-gazelle re introduction in Saudi Arabia and Partula tree snails to Polynesian islands.

Visitors to London Zoo can see ‘Conservation in Action’ in the Web of Life exhibition itself. The glass fronted breeding rooms allow visitors to watch the keepers as they work to save endangered species such as the British field cricket and the Partula snail.

Notes to Editors

British Field Cricket Facts:

Length:
17-23mm
Habitat:
Short tussocky grass and bare ground, which may be grazed by farm animals or rabbits, on chalky or sandy soils in the south-east of England.
Food:
Omnivores, feeding mainly on wild grasses.
Threats:
Modern farming methods in Britain have resulted in the loss of suitable management of heath grassland and down-land, with grassland becoming too tall and dense, or being invaded by bracken and scrub.

For further information and transparencies, please contact the Zoological Society of London’s PR Office:
Peter Beatty: 020 7449 6361
or Joe Laing: 020 7449 6236