Project Aims

The Expanding Painswick Valley’s Dukes and Blues project will build on Butterfly Conservation’s successes in the Painswick Valley landscape in Gloucestershire.

Further improvement and restoration of lowland calcareous grassland will help Large Blue and Duke of Burgundy butterflies strengthen existing populations and expand to become well established across 11 sites.

Key species

This project addresses the major conservation challenge of managing grassland sites for two rare species with different ecological requirements.

The Large Blue is the UK’s rarest and a globally endangered butterfly. This species has very specific habitat requirements and an extremely complex life cycle. Large Blue caterpillars feed on Wild Thyme and Wild Marjoram but plants are not the only nourishment they require. The caterpillars trick a particular species of red ant, Myrmica sabuleti, into thinking they are ant grubs in order to be carried into their underground nests, where they feed on the ant grubs before pupating. 

The Duke of Burgundy thrives where Cowslips and Primroses grow in high numbers. Their caterpillars prefer to feed on large plants, which do not dry out during hot weather.

Both butterfly species require shelter which can be provided by scrub, such as Blackthorn, Hawthorn or Bramble, but if this scrub begins to dominate, a site will quickly become uninhabitable. In the Painswick Valley the Duke of Burgundy is threatened by scrub and tree encroachment (particularly Bramble and Ash). Grazing livestock can also impact on habitat suitability.

Measures taken to support the Duke of Burgundy and Large Blue in the Painswick Valley will also benefit Dingy Skipper, Grizzled Skipper, Small Blue and Adonis Blue butterflies, as well as Burnt Orchid, Field Fleawort, Juniper, Purple Milk-Vetch, Slender Bedstraw and Adder.


The conservation work planned will:

  • Restore four hectares of lowland calcareous grassland, by clearing trees, thinning vegetation, scrub cutting, installing fencing and weed control across nine sites
  • Increase the breeding area for Large Blue and Duke of Burgundy butterflies by propagating and planting out 1,000 Wild Thyme plants on one site for Large Blue, and by collecting and scattering Cowslip seeds for Duke of Burgundy on two sites
  • Provide management advice on 11 sites and conduct habitat assessments on at least five sites; surveying for Large Blue caterpillar foodplants and host ants, plus butterfly monitoring
  • Reintroduce Large Blue to at least one site (subject to findings from habitat assessments)
  • Run two species monitoring workshops, to train local volunteers and land managers to monitor and manage for the target species. Ensuring conservation work is continued after the project ends.


Expanding Painswick Valley’s Dukes and Blues is managed by Butterfly Conservation’s Species Team, based at our Head Office in Dorset and overseen by Dr Caroline Bulman. The Project Officer, Sarah Meredith, coordinates the work; overseeing local contractors and volunteers to help with site restoration work, which includes scrub management, weed control, food-plant propagation and planting.

Highly experienced ecologist and expert on the Large Blue, David Simcox, is leading the research that underpins the project; undertaking surveys of food-plants, butterflies and ants and advising on targeted management, including scrub clearance and grazing regimes. The management and grazing on the project sites is carefully targeted using the results of habitat assessments, butterfly monitoring and ant surveys. Every site manager and or owner receives detailed advice on where to target scrub management with a tailored grazing regime according to the livestock used by their grazier.

Delivery period: July 2016 to December 2017


This project was developed by Butterfly Conservation in collaboration with Butterfly Conservation’s Gloucestershire Branch, Cranham Common Trust, Gloucestershire Wildlife Trust, National Trust, Natural England, Painswick Golf Club, Stroud Valley Project Group, Upton St Leonards Parish Council and private landowners.

Project Funders

Biffa Award, Summerfield Charitable Trust, Cotswolds AONB Sustainable Development Fund, Mackintosh Foundation, Cranham Common Trust

The project has also been made possible thanks to the generous gifts of Butterfly Conservation members and supporters. 

Where to Visit

The best site to see the Large Blue butterfly is at the Gloucestershire Wildlife Trust site Daneway Banks. This site is located just outside the project area.


Sarah Meredith, Conservation Officer (Large Blue), Butterfly Conservation


Large Blue Priority Species Factsheet

Duke of Burgundy Priority Species Factsheet