Many of you will have passed by “The Warren” – the steep slope along Valley Drive by Livingstone Road shops in Gravesend. But how many of you have stopped to explore this small open area of grassland? The grassland is sympathetically managed to encourage meadow plants and now would be a good time to visit. The 490 bus from Gravesend stops by the entrance. Sally and I visited a few weeks ago and we counted almost 30 flowering plants in the grassland. The large knapweeds looked good (it’s a good insect attractant too) and other highlights were Lady’s Bedstraw and the blue flowered Chichory.
Wild carrot was everywhere. We also saw some nice butterflies. But it was here at the Warren that Kevin found the white-letter hairstreak butterfly feeding on marjoram. So when he told me about this we just had to go back again! We had a great couple of hours. We found the butterfly feeding on marjoram, just as Kevin had found it. However the caterpillars feed on elm leaves – if we could find elm then it would be almost certain that there was a breeding colony of this very local butterfly on the Warren. Tall elms are a thing of the past. In Kent the tall majestic elm trees were killed, about 50 years ago, by the lethal combination of a beetle and a fungus – Dutch Elm Disease. However the remaining roots throw up fresh growth each year so new trees are produced. Sadly after a few years growth these young trees become susceptible to the disease and they die. This does look rather untidy and many landowners have now grubbed out the old rootstocks and replanted with other tree species. But there are many places where they have been left in situ. And that is what we found at the Warren. Adjacent to the surfaced path going diagonally across the site is a line of dead, dying and some healthy elm. Our white-letter hairstreak was only about 5 metres from the elms!
When I got home I started thinking. In Kent, tall elms were a feature of field edges not woodland. I thought perhaps the surfaced track on the Warren might be an old route. Indeed it is. It’s on the route of a public footpath branching off of Valley Drive and after getting a bit lost in Riverview Park estate reemerges to cross open ground (soon to be interchanges for the new Thames Crossing) before getting to Thong Lane and Randall Heath in Shorne Country Park. I checked on a old map (1860s) and this was one of the main paths out of Gravesend. No point going all the way into the valley as the steep climb at the end would have been very difficult for walkers and horse drawn carriages etc.
“Mr Bennet (a good botanist) called and we walked over to Cobham Hall and on our way caught some fine butterflies (the admiral) on the elms at Parrock and oaks on Randall Heath.” 1822
For a few moments I thought his elms might refer to those on the Warren but I suspect not. But the route is very clear on a map and so Pocock must have passed through the Warren. But he does not mention white-letter hairstreak anywhere in his journal. In the Victoria County History of Kent (1908), a Mr Goodwin is reported as having found the butterfly in Gravesend – but no more detail is given. The white-letter hairstreak was next reported in Gravesend in 1923 and 1925 by F. T. Grant. (source Chalmers – Hunt).
Grant was a well known entomologist and he worked as the Borough Engineer and Surveyor for Gravesend. He lived at 37 Old Road West. Not that far away – perhaps his records were from the Warren! Finally I looked at Eric Philp’s Atlas – The Butterflies of Kent (1993). This covers the period 1981-1990 and there are no records for the Gravesend area. It should be possible to find out if there are more modern records (Butterfly Conservation?) but as I mentioned in the previous post I am only aware of Julie’s record from her garden in Riverview Park and now Kevin’s sighting on the Warren itself.
I think it is highly probable that the elms were there when Pocock walked through. Could the butterflies have been there all this time? Quite possibly. Five sightings in 200 years. Well done Julie and Kevin!
Thanks to Sally for the photographs.