By mid June glow worms were being reported daily from widely scattered parts of the country. At Capenhurst in Cheshire on 16 June, Terry Wroe saw 79 on the former marshalling yard. When Pat Powell's car broke down on 19 June on the westbound A31 at St Ives near Ashley Heath she was surprised to see a glow worm at the bus stop layby – the first glow worm I've heard of waiting for a bus!

Sadly, many sites have very few glow worms this year. People are reporting sightings in single figures, rather than the dozens that many have seen in earlier years. For example, at Aston Rowant on 12 July I saw 12 in an area where in 2001 on 11 July I recorded 68, while on Gwithian Towans in Cornwall only two were seen in an area where numbers are usually well into double figures. The 2003 drought may well be responsible, as the larvae that hatched in that year should be maturing this year. But many may have expired shortly after hatching during the drought, being unable to find food. Glow-worm populations may be at greater risk these days than ever before, as many colonies are now isolated and the larvae are unable to spread to find better conditions.

However, it is always risky to compare one bad year with another very good one. The early 1990s for example seem to have been good, and at Aston Rowant I could see 40 glow worms at once from a single spot where today I would see none. But those occasions may have been as exceptionally high as this year was exceptionally low.

Dave Beech of Malvern reports good numbers seen in his garden this year so it's not all doom and gloom. And the autumn has brought quite a few reports of bright glows which turn out to be larvae revelling in the mild October, sometimes glowing almost as brightly as adults. It will be interesting to see if we get good numbers in 2006 and 2007 -- this autumn is completely the opposite from that of 2003 when we had drought conditions, so the mild, damp conditions should be ideal for glow worms. A few autumns like this one could result in bumper numbers again.

2004 reports
Reports were received from a number of sites that were new to me, plus many old favourites. If you saw glow worms during 2004, please let me know where you saw them by filling in the report form or simply by sending me an email saying where and when and how many. A grid reference is really helpful. I never publish details of sites on private land, so the location will not be revealed to all.

Population crash?
Two sites local to me near High Wycombe have no glow worms in mid July for the first time since I began studying them 10 years ago. A site that normally has a dozen or so in the peak of the season has only had two separate individuals earlier in July. Ann Sharp of Bourne End also found none at all in her garden, though she has reported them to me for the past 10 years. The major drought from July to October 2003 may have affected numbers. However, those in the car park at the Loudwater Travel Inn, the Papermill (see below) are still there – I counted four on 14 July, well away from the car park lights. The site at Aston Rowant had no glow worms at all on 28 July – normally I would expect to see at least a couple of dozen, if not many more, on this normally prolific site.

However, sites in other parts of the country have reported good numbers, suggesting that local conditions did play a part.

Here are a few individual reports of interest:
We live in Brittany, France (22810 Plougonver). We had not seen glowworms before as we have only just moved here and left the light on with window open only to find 20 or so males had come in. It was only when we were catching them to put back outside that one of them glowed green that we realized what they were! We will now make sure the shutters are closed so our lights don’t distract them’ -- Helen Hotson, 11 June[Comment: Only rarely do we hear of such large numbers of males in one place in the UK, though swarms have been reported previously. It would be interesting to know how close are the nearest female glow worms. This shows how easily glow worms can be distracted by artificial lighting]

We also hear that a site at Letty Green, Herts, has been virtually wiped out by the laying of a pipeline down the middle of a disused railway track. Where there were 11 glow worms last year, this year only one was seen. Hopefully the site will recover.

2003 reports

Thanks to all of you who sent in reports during 2003. As usually happens, these are mostly from ‘new’ sites – that is, new to me, not new to glow worms. They have probably always been nearby, but no-one noticed them before.

For example, Pam has found them in her garden in a secluded valley in Flintshire, the first one being spotted on 5 June. I have had no reports of glow worms for many miles around. She had never seen them before, and asks ‘What I would like to know is, how if from your survey on sites of glow worms you haven’t had any from this area, then how would they get up this far?’ For the answer, please see our Frequently Asked Questions page.

Two other interesting reports have been received from areas where glow worms are not common. In the past, glow worms were fairly widespread throughout Yorkshire, but recent reports have come only from the North York Moors area, plus one site near York. But in June, 16 glow worms were seen at Kippax, not far from Leeds, and a report was published in the Yorkshire Evening Post. Anyone in the area is encouraged to visit other possible sites – there may well be others. See our Counties list for a listing of formerly known sites in Yorkshire.

Jonathan Bell saw his first glow worm in 2002 near Sandown in the Isle of Wight. Now he writes (2003):

‘This year I've concentrated my efforts closer to my home town of Buckingham. I looked at the county records and noted that there was a sighting at Station House, Swanbourne, nr Winslow, on railway track (SP 800293)  June/July in 1967 ( bit of a long shot but thought it was worth a try – only approx 6 miles from Buckingham.)

I had a go at the end of May and early June but sadly no joy. Not to be put off I decided to visit the same site tonight (5 July) at approx 11.30 pm. Again no joy but after approx half an hour search and little further west / south west of (SP 800293) approx to grid ref (SP 796290) much to my delight I spotted a glowing female – shortly followed by another 3!

I later walked back to the original location (SP 800293) and spotted another glowing female – 5 in total! This site is typical of the sites that you mentioned that are worth looking at – although this is a disused railway the track and wooden sleepers are still intact, and all the glow worms I saw tonight were in the open on the track. Some were either perched under the sleepers at the edge of the track or amongst the loose stones – this made them difficult to spot so I may have missed some.

Weather conditions were good with clear skies, no real problems with artificial lighting here apart from the odd farm house. A road is nearby but really only a country lane so no real traffic to speak of... it’s reassuring to know that since the last recorded sighting here in 1967 they are still going strong!

It’s great that I found a site so close to home – will keep an eye on it and obviously let you know of any developments.’

Hopefully this will encourage other people to look at the old county lists and search former sites in future.

Reports have come in from many parts of England and Wales, and two from formerly unreported sites in Scotland. From my own point of view, things on my local sites near High Wycombe got off to a slow start, but by mid July numbers were well up. One surprising site was in the car park of the local Travel Inn, where up to seven glow worms were seen on the fringes of the well-lit area. It remains to be seen for how long this small colony survives with nearby lighting.
 

Glow worm at Travel Inn, Loudwater, Bucks, July 2003

2001 reports

Thanks to all the people who sent in reports. This is a summary of some of them.

Here is a report from Ron Beech of Portslade near Brighton:

Last Friday evening 22nd June 2001 we visited Southwick Downs above the tunnel that passes through the Southwick Hill on the A27. It was a calm night and we visited the site as we went with a party during our local Portslade Festival last year. Then the party found 12 female glow worms. We were not so lucky and found only five. On Tuesday 26 June we again visited the same part of the Downs. On the way up we found some. On the top where there was least light interference from the surrounding "town" we found most. The side that faced South had the most. Some we found as high as 18 inches from the ground but most were on short scrub plants  and some in the grass. We found 45 in the hour we were there. Such a wonderful evening. I have promised to go again next week.

One bonus on the Friday evening was we saw Mars very clear in the sky.

Should others wish to visit a good place to park a vehicle is on Mile Oak Road by the Mile Oak Pub. It is then possible to climb up to the top past the pylons between two bungalows on the short rise up from the pub.

As for my own records, the site at Aston Rowant, Oxfordshire (chalk downland) has finally begun to pick up in numbers, with 70 being recorded on a standard walk on 11 July, much better than at the same time in recent years.  This was once a prolific site, but in recent years numbers have been very disappointing. The wardens and I are keen to discover if changes in sheep grazing patterns or the increase of traffic on the nearby M40 (the hill is illuminated by car headlights) have affected numbers.

There is some evidence of a drop in numbers of glowing females in early July. We think that as the males tend to hatch out a week or so after the females, numbers of glows build up until the males all hatch out, then there is a mass mating and numbers of glows drop for a week or two. This makes it look as if numbers are poor, but in fact the colony might be very successful. See the picture below for evidence of what can happen when all the males appear.

Visits to the gravel pits at Harefield Place in Middlesex (adjacent to Frays Valley Nature Reserve) on 24 and 29 June resulted in no adult glow worms at all, though a few larvae were visible. This compares with 44 on 26 June 1995! This shows what a wide variation you can expect, and the message is that you should not write off a site on the basis of one visit.

The annual London Wildlife Trust glow-worm walk at this site yielded a count of 33 this year, compared with 71 in 2000 and 63 in 1999 on similar dates. So what has happened to them all? There are signs that parts of the site were heavily waterlogged earlier in the year (boards put out for anglers to walk over), so maybe many drowned when hibernating under leaf litter. But part of the site is an old embankment which should be well-drained. Maybe some predator had a particularly good year. When I first discovered the site in early July 1990 numbers were poor, so this is probably just part of the natural cycle.

On 2 July I saw no glow worms at Hitchcock's Meadows near Danbury in Essex. If I didn’t have other reports to go on, I might conclude that this was a very bad year for glow worms. But here’s an e-mail from Seth Gibson of Epsom, Surrey, dated 4 July:

'Last night after leaving the pub I was walking along the edge of the common and mentioned to my mate that glow worms should be visible sometime soon and that we ought to make a concerted effort to find and count them...with which he cried," Bloody hell! There's one!" In fact there were 13 glowing females in long grasses with 2 more on recently mown grass. The nearby sodium lighting did not appear to bother them although none were located in a similar area a mere 100 metres away.'

The picture below was taken on 1 July at Creeksea, Essex. Count the glow worms!

Answer: there is one female, who has three males clinging to her. She is facing away from the camera with one male clinging to her back, one on her tail (probably mating), one on her front and one in the grass to the lower right. There were several other females on the site which had not attracted a male.You can draw your own parallels with human behaviour. Photo copyright Robin Scagell

A visit to Stow Maries nature reserve in Essex on 15 July yielded 11 female glow worms, four males and two larvae. People often ask ‘how do you get to see the males?’. The answer is, ‘by looking at the females’. A brief look by torchlight doesn’t seem to disturb them, and you may notice the smaller male insect. Quite often by this time the female will have started to descend into the grass or some crack in the ground, so her light will be less visible even if it is still shining brightly.

Larvae are visible in dark conditions when they twinkle briefly – sometimes right on the path in front of you!

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For the major report published in 1992, please click here.