~ Robin Stamp
The Quantocks is a great place to see butterflies with 31 species regularly recorded including 4 of the UK’s rarest and most threatened species. Another three rare species (White-letter Hairstreak, Dingy Skipper and Grizzled Skipper) are still considered local but have not been seen in recent years which, if included, brings our tally to 34 of the UK’s 59 species!
What is more, our new ‘Nature of the Quantocks’ book (due to arrive in March 2025) highlights a further 6 varieties which were known to have been locally present but are now extinct and the three mentioned above also at risk (or even also now lost), meaning we may have lost almost 25% of our butterfly species within the 75 years that Friends of the Quantocks has existed.
Sadly, butterfly surveys carried out throughout the year on our own Quantock land (many thanks to our butterfly transect walkers) showed a 50% decline on 2023, mirroring the national results of this year’s Big Butterfly Count run by Butterfly Conservation and leading to Butterfly Conservation declaring a national butterfly emergency in September.
Whilst the weather is likely to be the greatest factor over the past year, habitat loss is certainly one of the factors affecting two of our rare Hairstreak butterflies. In the case of the White-letter Hairstreak (not recorded on the Quantocks since 2019), the butterflies like to lay their eggs on elm flower buds, however sexually mature elm trees are being lost to Dutch Elm Disease and very few young hedge elm are being allowed to grow on. In the case of Brown Hairstreak butterflies (no known records this year and only low single-digit numbers over the previous few) these butterflies tend to lay eggs on young stems or where new growth meets an older stem on blackthorn bushes. This location means that eggs are often destroyed as hedges are flailed.
The Elm & Hairstreak Project
So it is with the above backdrop that we have recently launched our Elm and Hairstreak project which aims to gather fuller data on White-letter Hairstreak (WLH) and Brown Hairstreak (BH) butterfly numbers; to plant trees and to encourage farming practices that preserve and enhance the habitat they require.
Hairstreak Butterfly ID Training day
On the 29th October we held a Butterfly ID training day in Combe Florey. We had 25 people attend and more that wanted to take part but couldn’t make it on the day.
Max Anderson from Butterfly Conservation provided the main training and was excellent as we all learned lots about the butterflies and how we can spot them throughout the year. Max pointed out that although small and hard to see, butterfly eggs have the advantage that they don’t fly or hide when the sun goes in, so looking for these and the caterpillars can really help to fill in the gaps in sightings of adults.
After the main training we all went out to Ash Priors common to look for (AND FIND) Brown Hairstreak Eggs in reasonable numbers plus Max was even able to show us a Purple Hairstreak egg which he found on a low hanging oak tree on the common. The day was a great success and we now have a decent-sized team of people ready and waiting to get started searching for butterflies and helping with the project as a whole.
How to spot White-Letter and Brown Hairstreaks (adults, caterpillars and eggs)
Adult butterflies -Hairstreak butterflies are among the smallest of our UK butterflies, all of which have a wingspan of less than 40mm, thus they do take some spotting. In the case of White Letter Hairstreak and Brown Hairstreak, they also only tend to be active when the sun is out and spend most of their lives up a tree which is not where you tend to look for butterflies, so it is unlikely you will see one without specifically looking for one on a sunny day!
White Letter Hairstreak spend almost all their life cycle in or very close to Elm, whilst Brown Hairstreak spend much of their time on Ash but do come down to lay their eggs on blackthorn.
Oh, just in case you thought 40mm was small, the reality is that for White-letter Hairstreak, what you are looking for is an 18-19mm triangle, as they always rest with their wings closed, simple eh!
Caterpillars- plainly caterpillars are even smaller than the adults, and again the WLH in particular don’t make finding them easy, as they live up a tree and are ridiculously well camouflaged. However they have recently been discovered (by Max) to fluoresce under UV light and thus we will be going out after dusk using UV torches to find them
Eggs-well surprise, surprise these are crazy small and certainly for the WLH this is really difficult as again they are found up a (mature) tree. As Brown Hairstreak lay their beautiful white eggs usually fairly low on blackthorn bushes (sometimes in groups), these are easier to find, particularly in the winter after the leaves have dropped.
Elm Tree and Blackthorn planting
We will be planting a mix of three different disease-resistant Elm tree cultivars (140 trees in total) and blackthorn bushes across the area between Bishops Lydeard and Crowcombe (6 separate farms/estates), which is the area where the last known sightings of WLH were recorded. The trees are expected to arrive in December and be planted (and protected by tree guards) in January, some by the landowners and some by our own team of volunteers.
This part of the project requires a significant financial outlay which has been largely covered by a successful FiPL (Farming in a Protected Landscape) grant application, with the remaining funds coming from our charity reserves and hopefully via new memberships and donations (hint hint).
Hedgerow management
In addition to the planting of new trees our hope is that we can encourage landowners to allow elm already present in many hedges to grow on and up into trees. We would also like to encourage landowners to allow areas of blackthorn to grow without being flailed on a 4-5 year rotation, such that some untrimmed blackthorn always exists.
Surveys
Our trained team are already out looking for (and finding) Brown Hairstreak eggs and will be out looking for eggs, caterpillars and butterflies in the new year, but a key focus for the new year will be the task of finding as many flowering Elm as possible.
Butterfly surveys
- November – March – Brown Hairstreak egg surveys, WLH are also possible but far more difficult!
- March – early June – White-letter hairstreak caterpillars surveys using UV torches; these can also be used to look for Brown (May-July), Purple (April-May), Green (May-July) caterpillars.
- Late June – end of August – White-letter Hairstreak on the wing surveys
- Late July – end of September – Brown Hairstreak on the wing Surveys
Please help us look for flowering elm
Mature elm trees do exist in hedges and woods across the area, although sadly many do seem to have recently died. Elm flowers emerge before the leaves in late February/March and then go on to set seed.
What we would like everybody to do is let us know of any Elm trees you see that have flower or seed on them (please make sure you don’t access land that you do not have permission to). This information will then allow us to focus our search for White-letter Hairstreak eggs, caterpillars and then butterflies where they are most likely to be present.
You can record any such sightings via the iNaturalist app, (making sure you share the location) or you can send us an email including grid coordinates or what3words location to [email protected]
If you would like to help with the any of the surveys or the project in any other way or if you own land and would be interested in planting elms, please do contact us on [email protected]
Join us today to help support this exciting project