‘This isn’t greenwashing’: thousands of butterflies surprise experts on restored West Sussex farmland
An "amazing" abundance of 5,290 butterflies, including rare small blues and dingy skippers, has appeared on Halnaker Hill farm in West Sussex, transforming barren wheatfields into a thriving wildlife habitat in just two years.
The speed with which nature has bounced back at Halnaker Hill farm has surprised experts after 133 hectares of intensively farmed land were transformed into a commercial nature restoration project. The farm's relatively unproductive soils on the South Downs were cropped for wheat for 40 years, but after a final harvest in 2024, the arable land was sown with a special wildflower mix.
Nature restoration project
Seven kilometres of hedgerows have been planted, seven hectares of new woodland created, three ponds dug and 54 hectares of herbal leys seeded, with carefully controlled mob-grazing on existing chalk grassland to improve its wildlife and biodiversity. Halnaker Hill Natural Capital derives its income from selling biodiversity net gain (BNG) credits, which enable houses to be built in the wider region.
Despite being tiny, the small blue is very good at sniffing out its foodplant, kidney vetch. I knew it would come, but what I didn't expect was it to come so soon and multiply so soon.
Biodiversity surge
Surveys found 547 small heath butterflies, and scores of common blues and green hairstreaks, alongside eight sulphur pearl moths, a highly localised species restricted to coastal areas of southern Britain. Hulme recorded 85 small blue butterflies and seven dingy skippers, which have never previously been recorded on the fields.
Some people are a little bit unsure about BNG and the idea of monetising nature, but projects like this are showing so clearly how BNG can deliver nature by the bucketload. This isn't greenwashing; this is the real deal.
Future plans
Halnaker Hill farm, which is delivering more than 850 units of BNG, forms part of the South Downs national park authority's "ReNature" programme, which is tackling biodiversity loss and adaptation to global heating in the region. More than 7,700 hectares of land is being transformed into natural havens.
Next year, Hulme is planning to reintroduce the rare Duke of Burgundy butterfly to the site, with wild pansies also being sown to attract the Queen of Spain fritillary, a once-rare migrant that is increasingly common visitor to southern Britain.
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