brown hairstreak butterfly spotted by katy eager-Nash

This article was written by Katy Eager-Nash who carried out an Environmental Survey at the Community Garden in 2023.

After spending many hours on my hands and knees rummaging through the grass, staring at tree trunks and shaking branches in search of bugs for my Masters dissertation, I decided that I wanted to do it all over again…and I knew exactly where! Nestled away at the top of the university grounds, hidden by its dense hedgerows, lies the Exeter Community Garden – a communal garden made up of individuals from the community, along with students and staff at the University of Exeter. Here, the gate is always open. Whether you want to eat your lunch listening to the birds chirp, go on a ladybird hunt, have a moment of mindfulness, or grow produce. The space is yours, to find your own special moment of joy in.

In Exeter, you treasure the days when the sun finally decides to make an appearance. One such day, while everyone was gardening, I was enjoying looking for bugs in the long grass, when one crawled right onto my arm, transporting me back to the traditional meadows of my childhood village. We sat and bonded for a while, enjoying the sun. It was then that I decided I wanted to delve deeper into the hidden life of the garden.

A beautifully sunny week in early September marked the beginning of my garden adventures. After a few hours sat under the medlar tree photographing beetles, bugs and spiders in the grass, I moved onto something a little bigger – butterflies. The weather was perfect for spotting some butterflies soaking up the sun, I thought. I was right! Within the first ten minutes, I had already seen around six meadow browns and large whites, gracefully dancing in their delicate manner. Deep in the middle of the vegetable garden, I saw another flash of orange come closer to me as it landed. Another meadow brown? It was clearly enjoying soaking up the sun, and stayed perfectly still for a little over a minute, revealing itself as one of the UK’s most elusive butterflies – the brown hairstreak.

Brown Hairstreaks are ‘nationally scarce’, having fallen victim of declining ash tree populations and drastic declines in hedgerows. Despite this, we are lucky enough, here in Devon, to have a stronghold of the UK’s population of these elusive animals. The brown hairstreak begins its life in the autumn, as an egg, found exclusively on young shoots of blackthorn trees – the exact place that brown hairstreak eggs were found at the garden a couple of months after my sighting. As spring arises, it begins munching the blackthorn leaves, in its new bright green caterpillar form, fattening up, ready for a short spell in its penultimate form, a chrysalis. By July, it has emerged as a butterfly. Now, in its most elusive form, the brown hairstreak will spend the majority of its time high in the tree tops and within dense hedgerows, making itself incredibly difficult to spot. Adults depend on one ‘master tree’, usually an Ash tree, where they will mate and feed on aphid honeydew. If you are lucky enough to see one come out of the tree tops, you might see them feeding on pollen from hemp-agrimony, fleabane, thistles and brambles.

Protecting this species is a crucial step towards conserving biodiversity and should be at the forefront of UK conservation efforts. Exeter community garden plays a vital role in these conservation efforts and can contribute greatly towards halting the UK’s rapidly declining biodiversity. The brown hairstreak is suffering a housing crisis, due to the increasing loss of woodlands and the annual destruction of hedgerows. The community garden provides an essential habitat for this rare species, containing many mature hedgerows and plants that are critical to the hairstreak’s lifecycle. Preserving habitats like the community garden, along with planting more species that the hairstreak relies upon, can help to provide a healthy home for the brown hairstreak and contribute greatly to UK conservation efforts.