Field Cricket Reintroduction

To breed and reintroduce field crickets into their former range in the UK


The field cricket, Gryllus campestris, is considered in Britain as an isolated genetic population of the Southern and Central European field cricket which lives in early to mid successional grassland. The species has very specific requirements for short and tussocky grassland with areas of bare ground. Its population in the UK has undergone a steep decline in the last century due to habitat loss caused by a number of factors including inappropriate management (under and over grazing), fragmentation and land development. By 1990 the population was reduced to a single surviving colony numbering fewer than 100 adults. In 1991 the species was placed on English Nature’s Species Recovery Programme (now known as the British Field Cricket Biodiversity Action Plan BAP).


The British Field Cricket Biodiversity Action Plan (BAP) was initiated in 1991 as an English Nature Species Recovery Programme with the mission to facilitate the establishment of ten viable field populations in areas of the crickets historic range. The goal of the associated conservation breeding programme is to provide the large numbers of nymphs necessary to establish new field populations. Appropriate sites within the cricket's historic range are selected by ’Natural England’, and managed by government or local conservation groups to maintain the grassland at an early successional phase (involving ground disturbance and grazing or mowing). As the surviving population was too low to support direct translocations the development of a conservation breeding programme was essential for providing the large numbers of late instar nymphs required for establishing (and where necessary subsequently enforcing) new field populations. Monitoring of released stock is carried out by field biologists.


The ex situ element is carried out at the Zoological Society of London’s Invertebrate Conservation Unit, with accompanying interpretation to educate and raise public awareness. To help clarify natural health profiles a faecal screening and post mortem protocol is in place and all crickets are screened before release. Between 1992 and 2005 the breeding programme has provided in excess of 17'000 late instar nymphs for the field establishment programme. Four of the seven field colonies established are still extant, the longest of which has persisted to the eighth generation.


WAZA Conservation Project 06014 is implemented by the Zoological Society of London with the support of/in collaboration with BIAZA, the Natural England, the Hampshire Wildlife Trust, the Sussex Wildlife Trust, and the British Museum of Natural History. 


> to project overview