River dipping again: messing about on the river 2014

A joyful sunny day down by the River Tale near Escot House, with youngsters and adults
engaged in all sorts of fun. My fun lies in looking in nets and buckets.

I like to try and identify what I see: I’m better with the big obvious stuff, to be honest, but I can tell the difference between a fox and a badger at least nine times out of ten…

There is a temptation on the part of youngsters to pull up a net and, if it hasn’t got any fish in it, to dismiss the net as empty. But if you look closer, and see what comes out of the debris at the bottom, you will find another layer of adventure and discovery. (And another one again, if you have some magnification to hand.)

The most spectacular insect we saw last year was also the first and last species I saw yesterday: a golden-ringed dragonfly (Cordulegaster boltonii) came to inspect me as I stood on the bank at the start of the day, and escorted me off the premises when I left.

Other dragonfly varieties were spotted during Sunday, but I couldn’t identify them with any confidence: I would guess they were from the genus _Libellula_, the chasers. With a decent photo I might have visited http://www.british-dragonflies.org.uk/ or
http://www.surfbirds.com/dragonfly-guide.html which I am sure would have sorted out the species.

We didn’t see much by way of butterflies: some small whites and a tortoiseshell passed through during the day. I expect more butterflies were up at the main gardens.

Lots of bees: the white-tailed bumble bee Bombus terrestris and carder bees Bombus pascuorum(?), as well as honey bees and a sprinkle of small solitary bees. A plant I didn’t know was absolutely covered in common wasps (Vespula vulgaris), and a couple of their kin were chewing at the wooden posts to make their carton nests.

I know little about flies but was attracted by a little blond sepsid abundant on the burdock: they have spots on their wings and wave them slowly, in a manner that irresistably reminds me of ground crew signalling to aircraft taxiing on a runway.
http://moving-wildlife.blogspot.co.uk/2010/07/insight-into-new-world. html

https://www.flickr.com/search/groups/?w=413853@N21&m=pool&q=sepsid nor http://www.ispotnature.org/search/node/sepsid were hugely useful in tracking it down and I couldn’t find a free key from
http://www.royensoc.co.uk/content/out-print-handbooks but a flick through the latest books by Chinery
http://www.amazon.co.uk/dp/0002199181/ and
http://www.amazon.co.uk/dp/0007298994/ turned up
a grass or cereal fly of the genus Geomyza as a likely ID, and they are Opomyziids, not Sepsids at all.

There were several specimens of the showy Banded and Beautiful damselfly species Agrion virgo & A. splendens – sometimes called demoiselles or jewelwings. I discover these days they are properly referred to as in the genus Calopteryx, meaning beautiful-winged. They mingled all day with the raft-builders and dam-makers and gold-panners. Other species were around too, maybe the Blue-tailed or Variable Damselflies.

The damselflies were also a group which were found in the river itself, as larvae: we found three vaguely different-looking examples, but this time I expect we would need not just a photo but a lens or microscope to identify them properly. Some nice clues are to be found at

The star turns of the day for me were two juveniles of the water scorpion, Nepa cinerea. I hadn’t seen one for 30 years or more, so finding one was a joy, then someone turned up another. We didn’t catch any, but there were many pond skaters of around; there are nine species I believe, although http://www.britishbugs.org.uk/systematic_het.html lists only seven. Gerris lacustris is literally the Common Pond Skater, but others are common too.

Several whirligig beetles were brought in, fun to watch whizzing around like dodgem cars on the surface of the water. Joke of the Day: “Oh, that’s a whirligig beetle. I’ve no idea why they are called that”. (The Latin is as good: Gyrinus natator =”swims in circles” – yes, they do.)

We turned up another fine water beetle, which I think now might have been Agabus didymus as being the species of Agabus that is most often found in running water.
(H/T Watford Coleopterists Group http://www.thewcg.org.uk/ )

Snails were pretty abundant: the only ones big enough for me to risk a ‘spot’ were I believe _Lymnaea stagnalis_, the UK’s biggest snail, but the ones we found were hardly that.

Among the rest were a number of fly larvae: worms swimming with twisting movements, and maggots weaving through the detritus. With a hand lens I might have had a better go at the two water mites I spotted, but I would have needed a microscope to do anything with the ostracods. And creating a bit of a stir were two leeches: I believe many leeches are vegetarian, but I chose not to put our specimens to the test.

The greatest excitement, of course, was created by any find of fish.

I was first off the mark with a couple of bullheads (Cottus gobio), which as a boy I would have called a Miller’s Thumb, a flat-spread fish of stones and gravel, which is pressed to the river bed by the flow of water over its body and fins. Also, a bit of a British speciality, I’m told.

We also turned up a couple of stone loach (Barbatula barbatula).

Small three-spined sticklebacks (Gasterosteus aculeatus) were found in in abundance, their little pectoral fins going nineteen to the dozen. We also pulled up a male and female of breeding size: a colourful red-bellied blue-eyed male and a grey pregnant female.

Other joke of the day: a young man proudly invited me to look in the bottom of his net, in which he had captured… a bubble. I explained that bubbles were quite rare in the river, but you could find them at this time of year as they migrate upstream to breed.



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One response to “River dipping again: messing about on the river 2014

  1. Pingback: Messing about on the River, 2016 | minorityattack

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