Exciting news for the Elms & Hairstreaks project, with our first two confirmed White-letter Hairstreak (caterpillar) sightings and a significant donation received meaning that he project will continue, with more trees due to be planted in the winter
It is with great excitement that we share these (rather poor) photographs of a White-Letter Hairstreak caterpillar (the first in 6 years) that was discovered during a nighttime survey, with a team of us staring up into the branches of mature Elm trees. Using specialist UV lamps, we were able to highlight the extremely well camouflaged White-letter Hairstreak (WLH) caterpillar fluorescing under a leaf. Following on from this confirmed sighting, a second WLH was found plus a small number of other fluorescing objects high up in branches have been seen which we believe to also be WLH.
We also saw various other fluorescing wonders, including the rather odd-looking egg sacks of Sputnik spiders, and shining bright white and pale green groups of shield bug eggs, all set against the strangely red underside of the elm leaves. Following training we received from the Butterfly Conservation charity back in October in identifying white-letter hairstreak and use of UV lamps, this was the first time we had put the lamps into action and dealt with the practicalities of surveying in the dark which does provide its challenges, not least in trying to get a clear picture!
White-letter Hairstreak butterflies are a rare sight locally and a high conservation priority in the UK, listed as section 41 species of principle importance. The adult butterflies are only 19mm (wings closed) and illusive, spending almost their entire life high up in and around elm trees, which are themselves at risk due to Dutch elm disease (a fungal disease spread by the elm bark beetle, that devastated the trees in the 1970s). There have been just 20 (now 21) records for the butterfly in the Quantocks area over the past 71 years, the last being in 2019.
Elm trees used to be a prominent tree in the Quantock landscape prior to Dutch elm disease, and the butterfly with it. Now, whilst small hedgerow elm are actually quite common, the disease also remains common, attacking and killing the trees around the time they reach maturity such that flowering trees around 20 years old (on which the butterfly breed) are an increasingly rare sight and one that the majority of people have never seen.
Thankfully the seeds (samaras) form prior to the leaves, covering the trees in light green cascades, and are quite a prominent sight once you know what you are looking for. Thankfully during March and April we identified more than 120 mature, flowering elm, the majority of which have been found in and around West Bagborough and Holford, with a scattering elsewhere, including East Quantoxhead, Cockercombe and Bicknoller.
Once we knew where the mature trees were, we were able to survey these trees for the caterpillars and make our discovery. Plainly we hope that many more exist and that we will go on to discover adult butterflies in the coming months.
Whilst it is great news that we have good numbers of mature flowering elm, the sad fact is that we have also seen an alarming number of dead elm and one of the flowering elm we discovered in Holford had signs that it was infected with Dutch elm disease. This was in an area with significant numbers of mature healthy elm, which could now be at risk. It is a sobering reality that it appears that most of the locations where WLH have been seen in the past have already lost the trees that the butterflies were seen on.
However, earlier this year we completed an initial planting of 141 disease resistant Elm trees, spread across 6 farms and estates between Cothelstone and Crowcombe and we are happy to report that these are looking very healthy. These then, when mature (in the next 5-10 years) will provide future habitat for these butterflies and all the other fantastic wildlife that also exist on them, hopefully growing into ancient trees free from the disease.
The next stage of the Elm and Hairstreak project will see us out surveying for the butterflies themselves which emerge from mid-June and fly until the end of July/early August, so please do keep your eyes open and let us know if you see any yourself.
The combined data that we have collected during the year will be used to select prime locations for a further planting of disease resistant elm which we hope to plant this coming winter. We already have a number of landowners that have requested to have trees planted on their land and it is our hope that many more landowners will come forward allowing the project to grow and have a significant impact.
It was a huge encouragement that we have recently received a significant donation to the project from Mr Peter Groves of Pennsylvania, USA, who as a young man lived and worked in the Quantocks Hills area and hiked these wonderful hills. His gift, along with grant aid we plan to apply for, should allow us to take the project forward into the coming years.
Friends of the Quantocks membership subscriptions and donations like Mr Groves’s allow this and other projects to continue and expand, providing a positive environmental impact now and for generations to come.
If you own land around the Quantocks and are interested in planting elm on it, or would like to make a donation or leave a legacy for the charity please contact us on [email protected]