Butterfly Surveys

Wall brown butterfly - one of many UK butterfly species that are in decline and are subject to local biodiversity action and conservation plans. Some butterflies are UK protected species.
Populations of butterflies like the Wall Brown are in severe decline, but mitigation measures adopted during development projects can help to reverse the trend and bring more butterflies back into our lives

Some British butterflies are protected species, so they and their habitats must be fully considered throughout all phases of development projects. This page outlines what might be involved in surveys and preparing mitigation proposals, whilst examples of how we have assisted project teams are available elsewhere. If you want to discuss how we might help with your project, please contact us.

Key Info:

  • About 6 species of UK butterfly are fully protected by Schedule 5 of the Wildlife and Countryside Act 1981, thus requiring planning proposals to include evidence of surveys and, where appropriate, mitigation measures and management plans to protect them.
  • Another 20 or so species have partial protection under the same Act, preventing their sale or being advertised for sale.
  • About 30 butterfly species are included as Priority Species in the UK Biodiversity Action Plan, so regional ecologists or environmental agencies may require management plans to be included with planning submissions to protect the insects and their habitats or to make Biodiversity Net Gain improvements to improve their prospects.

Surveys

The presence and significance of distributions of butterflies, its food plants or it habitats might be included in a Phase 1 Habitat Survey or Preliminary Ecological Assessment, dependent on the time of year at which it was completed.

Specific ecological surveys for butterfly populations, or potential populations, might also be required by ecological authorities and could include:

  • Checks of historic records for the distribution of either the butterflies or their main food-plant species.
  • Repeated Timed or Transect counts of flying adults – limited to spring and summer, depending on species.
  • Locating the species’ main food plants – leaves and flowers generally available May through to September.
  • Identifying caterpillars on food plants.
  • Searching for eggs – often limited to undersides of leaves and plant stems, so very time consuming with high possibility of missing them – June and July.
  • In some cases, locating larval webs made by young feeding caterpillars – generally in the autumn.