28. Diary Resumption – Canal, Tardebigge.




23rd June 2010. After a long period of inactivity, a bright summer day calls us to walk along a bit of the old BirminghamWorcester canal. To be precise, the flight of 30 locks beginning at Tardebigge. It stretches for about two and a half miles, as the canal negotiates the edge of the small plateau to get from Birmingham to Worcester, or vice versa, of course. What does the place-name ‘Tardebigge’ mean? Interestingly, the Oxford Dictionary of English Place-names tells us that in spite of Tærdebicgan being recorded circa. 1000 A.D. and Terdeberie (sic) appearing in the Doomsday Book in 1086, nobody actually knows what the name means – which is fairly unusual. Anyway, above you see the ‘Top Lock’ – number 58 I think – looking back in the direction of the tunnel, of which more anon., and on the right the view downwards from this lock.




Naturally, such a long flight of 30 locks – it is indeed the longest in the U.K. – requires a copious supply of water. Thus we have the Tardebigge Reservoir. The sluice-gate at the left allows water to go from the canal into the reservoir, I suppose in case of prolonged rain – which for once, we haven’t had this year. A little lower down the canal is the overflow or weir or whatever it is which lets water out of the reservoir into the canal; again I suppose, if the reservoir gets too high. But I don’t understand these things and there is doubtless an efficient system of separate conduits and feeders which does the daily task of keeping the canal topped up.




It is quite difficult to photograph a lake – unless you are high up. It just looks like a lot of water. The photo. of a part of Tardebigge Reservoir at the left could be anything really! But Google Earth is certainly high up – so I have er… borrowed from it, the image at right. This shows the size & shape of the reservoir. The canal runs from the top right of centre, and exits near the bottom of the left side. The straight, bottom left bit, of the lake is the dam: the land is descending from north-east to south-west, so that is all fine.



This is an interesting shot, if I say it myself. The canal was being heavily used by pleasure craft, and so lots of water was passing down. You can see that this lock is full to the very top. There are overflow channels that let surplus water by-pass lower locks, but in this case, and I’m not sure why, there was still too much water, and it is flowing over the top of the lock gates. It overflowed in cycles; obviously, long waves were passing to and fro between this lock and the one higher up. We all know that v = f.λ, where v is the velocity of a wave, f is the frequency and λ the wavelength. I should have timed the frequency, and estimated the wavelength, and worked out the velocity in my head. That would have been great fun, but to tell you the truth, I was getting a bit tired, because this little walk had been decided on without prior thought. Thus, in spite of the hot sun in the cloudless sky, I had no hat; was not wearing proper shoes but only sandals, and did not have my back-pack with me, containing a bottle of water. In short, my presence of mind must have deserted me. One group of boaters – of course you say ‘hello’ to everybody you pass on a British canal, did you know that excellent custom? – hailed me, saying affably: ‘Mad dogs and Englishmen go out in the mid-day sun!’ We all laughed, and I confessed my walk had been on impulse, and was indeed ill-equipped. However, they also assured me that there was a pub. at the bottom of the flight, and as nobody would joke about such a serious matter, I duly found it and settled down to a large glass of iced lemonade, a smaller one of Shiraz, and a cheese & onion sandwich.




So: after an hour or so, refreshed, we started back from the Tardebigge Bottom Lock on the left. It’s No.29, as far as I recall. On the right is No.31, framed by a bridge. The swirling water is coming through the lock by-pass. When we were about half-way back – it took us an hour and a half – we realised there was a blister on one foot. Oh dear – we are terribly out of condition, and should never have attempted to walk even 5 miles without proper shoes! However, we were to be presented with a most excellent Reward for our Endeavours. We had attempted to shoot a number of butterflies during the walk, without much success. True, a very worn Red Admiral ‘left over’ from last year, considerately settled on our trouser leg at one point; but it was facing downwards, but in the resulting photo., has raised the rear of its abdomen towards us in a very disrespectful manner. Therefore that shot does not appear here. What does appear below, is a species new to us:



Yes; the aching feet were well pleased with this photo! At first it seemed to be a Small Skipper, Thymelicus sylvestris – but when we consulted our main ‘Butterfly Book’, which is, as you know, Riley *, it emerged that it is more likely to be an Essex Skipper, Thymelicus lineola. This is because the tips of the antennæ are dark on the reverse and underside; while those of the very similar Small Skipper are unicolourous (he said, pompously). This individual is simply at rest, and conveniently remained so while we took no less than 15 shots of it. Still, it would have been better if it was feeding, because then they usually spread their wings and you can tell which sex it is, the males having a small line of scent scales on the forewing. But I’m not complaining. What a super little creature he/she is! And, if our identification is correct, out 10-14 days before usual – they normally appear in early July. But then we have had a lot of good weather lately. Indeed, a ‘forward’ season makes a pleasant change to the backward ones we have had in recent years…




Wearily, our feet trudged back up to the Tardebigge Wharf. Just past there, the canal enters the short tunnel – there are three on this canal I think. It was a profitable outing, not least because we were reminded to go properly prepared on future ones. We relaxed for most of the next day – well, we did clear out and tidy up the cupboard under the stairs, long overdue – , yet there was still an unexpected entomological bonus to come! With our feet propped up on a table in our little sun-room, reading a book and drinking tea, we because aware of a fluttering. A dark butterfly had entered the room. In a leisurely fashion, and with extreme nonchalance, we closed the sliding door, because I had seen one or two such dark butterflies during the summer of 2009, and seriously suspected The Ringlet – another species new to our camera. It proved to be so!



This is a very ‘coarse’ image, shot against the light, an unnatural posture on a plastic window frame… But it will do until a better opportunity comes along. Having said that, the underside of the forewing is almost fully visible, so it’s interesting after all. It is certainly a male: the upperside was extremely dark, and Riley tells us that the males come out in late June, over a week before the females. But if this is a ‘forward’ season, we shall have to keep a close watch on the garden. The ‘ringlets’ are usually well perceptible on the upperside of females.


* ‘British and Irish Butterflies’, Adrian M Riley. Brambleby Books, Luton, Bedfordshire, 2007. ISBN-13: 978 0 9553928 0 1






Page written 24th June 2010.