Hampstead Heath butterfly monitoring

Did you know that Hamsptead Heath is home to 28 species of butterfly? As we come to the end of our ecological monitoring season, find out about our butterfly monitoring programme from one of our volunteers, Leyla Wilson.

Small white

One way I could tell the seasons were changing this year was by seeing what butterfly species were flying on Hampstead Heath. I watched as the spring Orange Tips Anthocharis cardamines turned into the July boom of Gatekeepers Pyronia tithonus which led way to the Speckled Woods Pararge aegeria, and now, only a few migrants and Whites Pieris spp. remain. In fact, taking part in butterfly monitoring with Heath Hands was the highlight of my summer. While some of my friends went on holiday to exotic destinations, I stayed close to my flat and visited the Heath weekly for surveys.

I was already doing my own way of surveying Hampstead Heath before I started volunteering with Heath Hands. This involved me walking around the Heath trying to find butterflies and other fascinating insects to photograph. So, joining the Heath Hands wildlife monitoring program was a natural next step and gave me more structure. It has also been a great experience for me as I aspire to be a field ecologist after completing my studies. When I first started, I had no experience in butterfly identification, but the staff and volunteers at Heath Hands were very encouraging. Soon, with the help of a few handy ID guides, I was identifying butterflies in flight.

On survey days, the weather was carefully considered (temperature, the amount of sun and shade, the wind force and direction) and was in fact often the best and sunniest few hours of the week. Walking the transect, I kept my eyes open for any movement on and around the ground, as well as on hedges/bramble and on the lower branches of the trees. After a while I got the hang of it and was sharp-eyed at spotting butterflies.

Peacock butterfly (Aglais io) near Parliament Hill

This summer I was fortunate enough to observe 17 out of the 28 butterfly species recorded on the Heath. Perhaps my most amazing find was the Purple Hairstreak Neozephyrus quercus by the Oak tree near the model boating pond in August. The species name ‘quercus’ refers to the fact that their caterpillars feed on Oak Quercus spp. and adults are most often seen fluttering high up in oak trees on warm summer afternoons. Although I didn’t manage to get a picture, the butterfly rested on a branch long enough to ID it. Other favorites include the majestic Peacock butterfly Aglais io, aptly named for the eye-spots on its forewings, and the Common Blue Polyommatus icarus whose caterpillars feed on Bird’s foot trefoil Lotus corniculatus in the Heath’s grasslands

Common Blue (Polyommatus icarus)

Although the survey focused on butterflies, we saw some dazzling day-flying moth species as well, such as the Silver Y Autographa gamma, Six-spot Burnet Zygaena filipendulae, and Jersey Tiger Euplagia quadripunctaria. While we may differentiate between butterflies and moths by features such as clubbed antennae, smaller bodies and larger wings, there is actually no difference between them. In fact, butterflies and moths both belong to the order Lepidoptera, with butterflies belonging to one of several superfamilies within it (the Papilionoidea). So butterflies are technically a group of moths!

Six-spot burnet moths (Zygaena filipendulae) - photo Leyla Wilson

Monitoring butterflies is important to observe trends in populations, as unfortunately there is an overall decline in butterflies across the UK. This can be attributed to habitat loss and fragmentation which reduce and limit the available habitat for all stages of their life cycle, while the use of pesticides and herbicides directly affects butterflies and their food plants. However, Hampstead Heath provides a diverse patchwork of habitats for butterflies from sandy heaths and meadows to covered forest, so it is an ideal place for many species to live and to survey for them. The records gathered on the Heath help to inform the work of the City of London’s conservation team to manage the Heath’s habitats.

I would encourage everyone to go out into nature, maybe in search of butterflies, but if not, I think every little bit is beneficial. You can find out more about Heath Hands wildlife monitoring and get involved here. For more information on the butterflies of Hampstead Heath, read our ‘Beautiful butterflies’ blog and to find out more about nature on the Heath, check out Heath Hands’ regular nature walks.