Red List of Butterflies in Great Britain

Red Lists are standard, objective way of assessing the extinction risk of species at global, continental and country levels. Butterfly Conservation has recently revised the butterfly Red List for Great Britain (butterflies in Northern Ireland are covered by the Ireland Red List) using data kindly provided by thousands of volunteers via our recording and monitoring schemes. The new Red List categorises half of Britain’s remaining species as threatened (Endangered or Vulnerable) or Near Threatened.

The current GB Red List category for each resident, former resident and regular breeding species is given in the table below, alongside brief reasons for qualification and the category in the previous Red List published in 2010. More detailed information on the qualifying criteria for each butterfly species can be found here (downloads as an Excel document) and an overview of the whole process in Fox et al. 2022.

It is worth noting that the IUCN Red Listing process is complex and prescriptive. Some key points to bear in mind are that it is an assessment of extinction risk and not conservation priority, that rarity alone is not sufficient for Red List qualification (at least for the IUCN criteria that are applicable to GB butterflies) and that historical declines that have now ceased are not relevant. We used smoothed trends for abundance and distribution data to minimise the problems associated with measuring short-term trends for species, such as butterflies, with populations that naturally vary greatly from year to year.

Richard Fox
Head of Science