Phillip Cullen, 57, a butterfly collector from Cadbury Heath, Bristol, was convicted on Thursday 16 March of capturing and killing large blue butterflies at two nature reserves in 2015.
Witnesses said that they saw him attempting to catch the large blue butterflies with a net, though he claimed he was trying to catch parasitic wasps.
When police searched his house in February 2016, they found a collection containing dead large blue butterflies, and a number of other protected species, including heath fritillary, high brown fritillary and swallowtail.
“The Large Blue is a globally endangered species,” said Nigel Bourn, one of the directors of Butterfly Conservation, “and a long-term effort has been made since 1983 to re-establish the butterfly in the UK.”
“We welcome this prosecution and commend the hard work of the National Wildlife Crime Unit in bringing together evidence for this important test case.”
The large blue butterfly went extinct in the UK in 1979 and has since been reintroduced to selected sites in southwest England.
This species is one of six butterfly species in the UK which are fully protected and cannot be collected, killed or sold.
Cullen will be sentenced on 7 April at Bristol Magistrates Court.
Main image: Large blue butterfly © Alex Berryman