With all preparations complete, the plan was to relocate the Grizzled Skipper eggs from Warwickshire in early June, but the hot spell throughout May caused the eggs to hatch earlier than expected. After a last-minute change of plan, 10 adult butterflies were transported to Calke and released into vegetated areas, with another 11 eggs placed in secure conditions, where they will grow into adults and be released into the Calke Estate next year. Following a bout of heavy rain, the rangers returned to the relocation site the next day to create further egg-laying sites, by placing stones and pieces of wood underneath wild strawberry plants. This is called ‘stone seeding’ and provides better conditions for the butterfly to lay eggs. At this stage, it’s difficult to measure the success of the reintroduction of the Grizzled Skipper, but the ranger team at Calke are hopeful to see more of this rare butterfly next summer.
Butterfly project at Calke Abbey
The Grizzled Skipper was recorded in the wider Calke Estate during the 1940s and 50s. Over time, tree and shrub cover increased in the area, closing off much of the open floor and banks that contained the butterfly’s food plants, wild strawberry and bugle. Now, the National Trust is working in partnership with Butterfly Conservation and Natural England, to embark on a project to reintroduce this increasingly rare butterfly species to the estate.
Looking after the habitat
Since the National Trust took over the management of the Calke Estate, it’s been a priority to restore a healthy, natural environment where wildlife can thrive.
In the site where the Grizzled Skipper will be introduced, several trees were removed to open up the area, then Hebridean sheep were introduced to graze off the regrowth. This has encouraged the growth of grassland and plants that love the calcium-rich soils, such as the Common Spotted Orchid and the Fragrant Orchid.
Preparing for the Grizzled Skipper
Due to its geology, the Calke Estate was suggested by Butterfly Conservation East Midlands as the first site in Derbyshire to reintroduce the Grizzled Skipper.
" Before this lovely butterfly disappeared from Derbyshire in 2007, Calke was an important site for the species and it was once there in good numbers, so it’s very fitting that this was chosen as the location for the re-introduction."
In recent weeks, the ranger team at Calke have removed some more tree cover from shading the spoil heaps and banks. The butterflies need lots of sunny areas for the caterpillars to develop and thrive. We’ll also be raking the grass banks to open up bare soil, to encourage more of the caterpillars’ main food plant, wild strawberry, and reintroducing wild strawberry in open areas that don’t currently have any.
Looking after the Grizzled Skipper
The project to reintroduce the Grizzled Skipper is in partnership between Natural England, Butterfly Conservation and the National Trust.
The project is also being overseen by Butterfly Conservation’s Mike Slater, who’s been involved with successful wildlife reintroductions in other counties.
" I visited Calke in March and was extremely pleased with the work carried out so far – the project has now been approved and the Grizzled Skipper eggs will be relocated from Warwickshire to the Calke Estate in June this year. This really is a great opportunity to bring this butterfly back to Derbyshire. "
How will we know if the re-introduction had been successful? Every week, the rangers at Calke complete a butterfly transect – a survey to record butterfly species in the area, and their numbers. The route is walked once a week between 1 April and 30 September, and the results are sent to Ken Orpe, the County Butterfly Recorder.
This year’s transect, which is completed with the help of our volunteers, will give us an idea of what we have now, before we introduce the Grizzled Skipper later this year. It will also help us to monitor how well the Grizzled Skippers do, and allow us to alter our management of the project accordingly. We hope to see lots of butterflies over the summer!
Keep an eye out for more updates to this page, coming soon.