Conservation Projects

Returning the Chalk Hill Blue to Warwickshire

This innovative project will restore the threatened Chalk Hill Blue butterfly to Warwickshire after an absence of over 100 years.

The Chalk Hill Blue has not been a resident species in Warwickshire since the 19th century, however in recent years, individual butterflies have been sighted in the south of the county, and it is believed that the species is looking for new sites to colonise. Conservation measures in neighbouring Gloucestershire and Oxfordshire have allowed the Chalk Hill Blue to recover some of its former range, meaning that colonies are now found very close to the Warwickshire border.

The main threat to the Chalk Hill Blue is loss of habitat through inappropriate habitat management. In the UK between 1972-82 and 1995-2004 its distribution declined by 36%, and from 1995-2004 its population declined by 34%.

The larval food plant of this threatened butterfly is Horseshoe Vetch, a plant restricted to well-drained, mainly south-facing calcareous grassland slopes; this plant is currently extinct in Warwickshire. Locally-sourced plug plants of Horseshoe Vetch, the Chalk Hill Blues larval food plant will be planted on eight project sites, creating breeding habitat and enabling this beautiful butterfly to recolonise the county.

Through this project, scrub clearance will be undertaken by specialist contractors, ensuring that the habitat is optimal for the Horseshoe Vetch, and locally-sourced plug plants will be planted on each of the eight ecologically-linked project sites.

Other scarce butterfly species will also benefit, including Small Blue, Dingy Skipper, Grizzled Skipper, Green Hairstreak and Dark Green Fritillary, and other threatened invertebrates including Chalk Carpet moth, Dotted Bee-fly and Large Garden Bumblebee.

Volunteers will deliver a programme of targeted habitat management in order to create suitable breeding areas for the Chalk Hill Blue.

In summary, work will involve:

• A programme of scrub management to create open habitat and increase connectivity between project sites. This will be undertaken by specialist contractors and volunteers.
• Monitoring of habitat condition and butterfly responses undertaken by volunteers.
• Recruiting new volunteers through a programme of public events including guided walks and talks.
• Delivering a programme of training days for volunteers.
• Working closely with Butterfly Conservation’s Warwickshire Branch, landowners and other local community groups to raise awareness of the Chalk Hill Blue and other rare and threatened species in the area.
• Producing a final report for distribution to landowners and funders.
  
  

The long-term success of this project will be measured through ongoing species surveys, monitoring and habitat condition assessments which will record:

• The area of suitable habitat restored.
• The habitat quality and abundance of Chalk Hill Blue on project sites; the target is three established colonies by 2022.
• The abundance of other moth and butterfly species across the project sites.

This will allow us to make a careful evaluation of species and habitat recovery across the project sites and prioritise future conservation effort and ongoing sustainable management in this important project to restore a currently extinct species to its former range.

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