Searching for Clubtails at Goring, 1 July

Further to the earlier post on the remarkable Clubtail records from 1 July, I am very grateful to Alan Holmes for providing the following account and photograph.

Note that in addition to their Clubtail sightings, Alan et al reported no less than 3 Lesser Emperors!

Stephen Burch

Clubtails in tandem flight (c) Steve Cham

On Tuesday 1st July, Steve Cham,  John Van-Gowler and myself were looking for larvae and copulating females as part of a scoping exercise to investigate the feasibility of reintroducing clubtail larvae to an old New Forest site. The idea was either to catch enough larvae or alternatively raise up eggs from a gravid female and release them. In the UK, larvae take two years before emergence, though up to 4 years at some German sites. Occasional September adult records indicate that occasionally UK larvae develop fast enough to emerge earlier, late in the season after their emergence.

Four larvae were found by John and Steve in the finer silt round reeds with none being found further out in the river. In common with other Gomphus species, larvae have a special spine or tooth at the tibial tarsal-joint of the front and middle legs which is absent on the hind legs which is thought to help with digging through the substrate.

At least 5 males were seen flying over the centre of the river and one was seen engaging with a female who initially resisted, resulting in the pair hitting the water before flying up into the air above the river and landing in the willows on the south bank. 

Seeing Clubtails at Goring in the season seems fairly reliable on the classic walk along to the railway bridge but the numbers do not seem to be viable for catching a female or getting enough larvae on the Thames. Numbers of individuals seen on the Severn seem to be significantly higher where the season is a little later (the average exuviae record on the Thames is the 21st of May, and the 26th of May on the Severn.) There are records this year on the Thames all the way along from Windsor up to upstream of Oxford but at very low densities.  Often these records are from members of the general public rather than dedicated dragonfly, naturalists.

At Goring, it is very easy in season to find the exuviae on the concrete bridge parapet and in culverts. But this would be much more difficult among vegetation further upstream. This would require a thorough search by canoe as has been done historically. 

Alan Holmes