Large Tortoiseshell Butterfly Declared Resident Species in the UK

Significant Milestone for Butterfly Conservation

The large tortoiseshell butterfly is now a resident species in the UK after being declared extinct in the last century. This marks a significant milestone for conservation efforts, particularly for Butterfly Conservation, which has documented this change in its 58-year history.

Recent Sightings Across the UK

Recent sightings of the large tortoiseshell have been reported in woodlands across Kent, Sussex, Hampshire, Dorset, Cornwall, and the Isle of Wight. The butterfly’s return has increased Britain’s native butterfly count to 60, highlighting a positive trend in biodiversity.

Historical Context of the Species

The large tortoiseshell butterfly last flourished in Britain during the 1940s before it was considered extinct by the 1960s, primarily due to factors such as Dutch elm disease. Its absence from the UK for decades makes its return particularly noteworthy.

Breeding and Habitat

Confirmation of the butterfly’s breeding in Britain came when caterpillars were found feeding in the wild since 2020. These caterpillars feed on elm, willow, aspen, and poplar, which are essential for their development. The large tortoiseshell hibernates as an adult and emerges in spring to mate and lay eggs, with adult butterflies from this year’s offspring expected to take flight during midsummer.

Reasons for the Comeback

Experts believe the large tortoiseshell’s return is linked to population rises in the Netherlands and France, as well as climate change, which may have created more favorable conditions for the species. Richard Fox from Butterfly Conservation stated, “The signs are really positive, which is lovely,” emphasizing the encouraging nature of this development.

Public Involvement Encouraged

Butterfly Conservation is actively encouraging the public to log sightings of the large tortoiseshell using the iRecord app. This initiative aims to gather more data on the species’ distribution and help monitor its progress as a resident butterfly.

Future Observations and Uncertainties

While the large tortoiseshell has been classified as a resident species, details remain unconfirmed regarding its potential to become widespread across multiple landscapes in the UK. Richard Fox noted, “We’re still in that zone of uncertainty at the moment, but there are exciting signs,” indicating that ongoing observation will be crucial for understanding the butterfly’s future in Britain.