Rare butterfly hits purple patch at Sussex rewilding project

Ecologists say 283 purple emperor recordings on one day at Knepp signal higher numbers nationwide Elsie McDowell Fri 4 Jul 2025 17.00 BST

A conservation project in West Sussex has had its best day on record for rare purple emperor butterfly sighting, and ecologists say they are confident the species is doing well nationally.

Purple emperor populations steadily declined over the course of the 20th century but they have been slowly recolonising the landscape at Knepp since 2001, when Isabella Tree and her husband, Charlie Burrell, decided to turn the stretch of former farmland into a “process-led” rewilding project.

Ecologists at Knepp recorded 283 purple emperors on 1 July alone. Since the site boasts the UK’s largest population of the butterflies, the ecologists said they were confident the numbers were high nationwide.