www.ukbutterflies.co.uk

Does anyone know of any mitigation sites in the UK for Grizzled Skipper? This may are may not have been successful or necessarily involved the translocation of Grizzled Skipper. We are trying to find examples to inform a proposed development on the margins of the only Grizzled Skipper metapopulation in Essex.

We only know of the one at Over, Cambs.

regards
Rob Smith
BC - Cambridgeshire & Essex branch

Hi there
I'm certainly no expert at this topic. But I do remember reading a bit about it in relation to Grizzled Skipper colonies on an industrial site near Wrexham. From what I remember, there were previously two colonies on Brownfield sites. However one was built on, and as part of the planning permission, had to relocate the colony to another site nearby. Sadly it failed. I have no idea whether the relocation was monitored or carried out properly, but disappointing all the same. Might be worth contacting Butterfly Conservation North Wales to find out if they have more info about this particular case, or Butterfly Conservation HQ for official national advice. I'm pretty sure they'd be able to help you out with advice as I'm sure this sort of stuff happens all the time.
Paul

I too only know of the Over Cutting site in Cambs...

The mitigation site there is a very brave attempt to help the skippers from the original cutting and there has been a lot of work done to make it as acceptable as possible. If there are any take-home messages about similar projects, I think one of them might be to try to shelter at least part of the site from wind. Being on the edge of the fens, the nearby fields are often affected by strong winds... Thats why there's a windmill within a few yards of the place! Sheltered areas with horse-shoe shaped piles of rock/soil and an embankment along one edge of the (flat) mitigation site have been built, but these are not very high and it is often still windy up there. The few Grizzled Skippers I've seen on the mitigation site itself (so far) have been very close to the cutting itself and they don't seem keen to travel too far from the protection of the main cutting. I'm sure the fact that the edges of the cutting were spared the dreaded concrete mixer during the building of the guided busway has been the real secret and the species is still using the plants growing there in preference to those in the adjacent field. The dark clinker from the original railway track was kept and scattered on the cutting edges and this helps to heat the ground up in the sunshine. I did wonder whether the bus track was going to be dark, but that may have encouraged the skippers to sit on it to warm up there in the mornings which may have led to numbers being hit by the busses. As it is, the light-coloured track reflects a lot of the sunshine and heat onto the slopes and that must surely be good. It is a pity that a concrete bus-route had to be built along what was already there - an old railway track, but thanks to many people, the Grizzled Skipper has been helped as much as possible in that area.
Patches of large stones criss-crossed with wire (to stop the rabbits eating right down to the bases of the low-growing plants) have been tried to encourage the creeping cinquefoil to flourish on the mitigation site. The population of rabbits normally helps to crop the vegetation as it grows and to allow the low-growing foodplants of the Grizzled Skipper to keep a foothold in the cutting. This year, the wet weather has caused very fast growth of taller plants and (in common with the known venues in Essex I think) a lot of the foodplant seems to have been swamped. I hope this doesn't affect the population next year, as I believe the species had a poor season in the two counties this term. I have my fingers firmly crossed for "Little Griz"


NB: On a personal note, I really wish the authorities would stop using their preferred method for counting the guided bus "passengers" when the subject is mentioned in the media... The figure quoted on the news last week was 5 million passengers since the busses started running(!?). There have obviously been a considerable number of people using the busway, but to suggest that taking someone from one bus-stop to the next constitutes a "passenger" (and therefore allows them to multiply the people on the bus by the number of stops they go past) smacks of extracting the urine somewhat. Anyway, nuff said.

Trev

Thanks very much Paul & Trev.
All good ammunition. I can understand that you would have to put a lot of work into a nearby site, otherwise it would have been colonised already. Creating the windbreaks would be a cheaper way of keeping any scraped topsoil on site.

Rob