On a warm summer’s evening I love to wander over Cobstone Hill, above Turville in the Chilterns, looking for glow worms.
Our first summer here was 1988 and we saw our first glow worm on 20 June (my first ever). I can see from my diary that I was ecstatic. Two days later the glow worm was there, in the same place! The following day I record that ‘I walked up to the glow worm but it wasn’t switched on tonight’.
The glow worm is in fact a beetle, Lampyris noctiluca, and it is the female which glows to attract her mate.
Skimming back through my diaries it seems that the best year was 1999. We saw the largest number ever, 24, on 25 July 1999, and on many evenings the sightings were in double figures. It wasn’t very scientific but we tended to walk the same round, up through the wood, along an open track and down across the grassy hillside.
My earliest sighting was 12 June in 1989; the latest by a long way was 23 September in 1997. I have good numbers from the end of June to mid-August many years, though fewer in the last ten years. It could be that I am getting lazier in the evenings, or that the grass has grown longer—or both. One year we saw a glow worm four feet up a tree.
In this part of England the poor glow worms have to compete with the blazing security-lights from the village. Our planning laws don’t prevent this ghastly nocturnal pollution.
Inspired by The Living World, on radio 4 on Sunday 4 August, I recorded the glow worms I have seen this year on the UK glow worm survey website. Robin Scagell, who runs it, has since asked me to provide my past records for Cobstone Hill, so it’s lucky I kept those diaries. If you have seen any glow worms, do complete the online survey form.