Welcome to the Ridgeway Glow-worm Survey.
The chalk hills of southern England are among Britain's most distinctive habitats and home to many rare and charismatic species. The common glow-worm, Lampyris noctiluca, is found in many parts of the UK's downland, but like those of so many other insects, their numbers have been declining over the last century. Even with the hard work of many enthusiastic observers, data on glow-worm populations remains sparse.
Lampyris noctiluca - by Tero Karppinen
The Ridgeway glow-worm survey will run in summer 2027 and aims to get rigorous population data along a 40km section of the Ridgeway - an ancient byway that runs along the northern edge of the hills of the Wessex Downs. In the region we are surveying, the Ridgeway is a car-free path with large grass borders and forms a long, natural transect. We aim to survey the whole of this transect simultaneously on a weekly basis. By doing this we will get data on when and where glow-worms are present, and equally importantly, when and where they are not! This data will help us understand what factors are affecting their populations, and will ultimately help with their conservation.
In summer 2026 we did a pilot study, a report can be found below. This contains summaries of the 2026 data, some analysis, plans for the 2027 survey and motivation for its methodology.
The Ridgeway at Sparsholt - by JimChampion
Volunteering
You don't have to be a glow-worm expert to join in!
One person can only cover a small part of the Ridgeway in an evening. We're looking for enough volunteers to cover the whole of the Ridgeway between Bishopstone (near Swindon) and the A34 at Harwell (near Didcot).
We are looking for about 20 volunteers, but it would be difficult for us to have too many. We can always cover more of the Ridgeway, have bigger groups, and use the greater numbers to plan in a way maximises volunteers' chances of seeing glow-worms.
What volunteering entails:
- Attending a briefing meeting in early June (potentially online)
- Walking along the Ridgeway at night, in groups of at least 2
- Covering a section of 1-4km
- Logging glow-worms with a smartphone
- Approximately 10:30pm to 11:30pm, every Saturday for 4-6 weeks
- June and July, exact dates to be determined based on weather
Other roles:
- Driving people to the start, and from the end of their sections
- Assisting with the site that is monitored every two days and assessing the abundance of males
- Helping with planning, administration, website, etc
Contact
If you want to get involved, send us an email, and we can add you to our list of volunteers. We will be sending out emails with more details in the spring.
2026 Pilot Survey
Download a report about the 2026 pilot survey here.
This contains last year's data, some interpretation, research questions, and an outline for the 2027 survey.
Image Credits
Glow-worm: Tero Karppinen, CC BY 2.0, via Wikimedia Commons
Ridgeway: JimChampion, CC BY 4.0, via Wikimedia Commons