White-letter Hairstreak Recording Project

Welcome to the home page of the White-letter Hairstreak (Satyrium w-album) Recording Project

The White-letter Hairstreak butterfly is a Priority Species in the UK Biodiversity Action Plans [BAP], due to population declines picked up by the British Monitoring Scheme [BMS]. However, this is a small and somewhat elusive arboreal species that can be quite difficult to monitor effectively when using the standard transect recording method.

Given an adequate level of targetted surveying for both elms and White-letter Hairstreaks in a number of random sample areas, the project aimed to provide enough information to create a reasonable model for estimating the likely spatial distribution and occurrence of White-letter Hairstreaks at a landscape level. The project also established the likely present range of the species, and to what degree elms could be used as a proxy for White-letter Hairstreak distribution.

The three year project period ended in 2009 but we hope the following pages will encourage recorders to continue looking for this elusive butterfly in future years. We would like to thank everyone that has contributed.

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The Future?

Since the project ended, there has continued to be an interest in recording White-letter Hairstreak, although the distribution maps show that their are now many gaps. We have not been able to dispel the myth that the species is really hard to find!

The range of the species is expanding as was first being noted by our project, especially in Cumbria where we only found two new 10 km squares in the south. The butterfly is now quite widespread along the River Eden and its tributaries, although unlike some other river systems in the north, the river flows northwards, thus not connecting with known areas.

An adult butterfly was recorded in East Scotland in 2017 near Berwick-upon-Tweed. On 4th February 2018, the first eggs including a hatched egg which would have been laid in the 2016 season, were confirmed in Scotland beside the River Tweed near Coldstream. These records represent a jump of between 25 and 30 miles from the previously known most northerly site at Rothbury. Two weekends later, more eggs were found along the River Teviot in three different 10km squares! In the hot summer of 2018 further adult finds were made and more eggs have been found this winter (2018/2019).

There has also been a notable return to Cornwall although it would appear at a slower pace.

With additional survey work by Iain Cowe, helped by Ken and Jill and Martin Greenland, more eggs and adults have been found in 2019 and the 2020 season is still young (9th July 2020)

In 2019 Ken and Jill recorded White-letter Hairstreak on Anglesey, possibly the first known record!

What is signficant though is the interest in planting Disease Resistant Elms to replace elms that have succumbed to Dutch Elm Disease. Many Butterfly Conservation Branches are actively involved with projects to plant more elm in their local landscapes and to raise awareness with planning authorities and other bodies of the continued importance of elm and the White-letter Hairstreak butterfly! Copperdock surveys http://www.copperdock.co.uk/index.php