Overall, this week has been fairly mundane with a couple of rainy days working in the office and the rest of the week removing invasive non-native plants (see Plant of the Week below).
However, on a sunny Wednesday morning a few of us got the opportunity to join the Wales Reserve Ecologist, Gareth Fisher, for a bit of Welsh Clearwing moth surveying. We surveyed known clearwing areas to see if any were emerging and to decide what management would be required to improve the habitat. Welsh Clearwing larvae feed in mature birch trees with the larvae burrowing through the bark and feeding inside until ready to emerge. They are usually found up to 2m from the base of the tree where they are more likely to be exposed to the sun. There were a good number of promising looking trees and a few exuvia (casing of emerged insects) indicating some adults had emerged recently.
Welsh Clearwing exuvia (Photo by Gavin Chambers)
While looking very closely at the bark of one Birch I noticed a small micro moth tucked in to a crevice. Having flicked through the micro moth book numerous times this one didn’t spring to mind. Fortunately Gethin had a camera with a decent macro setting and managed to get a reasonable, OK... very good, image of it given its size of 7mm in length.
Denisia similella (Photo by Gethin Elias)
Once back at home I immediately got the micro-moth book out and found what appeared to match the image. The description also mentioned the fact that the larvae feed on types of fungus, which can be found on old dying Birch. However its range/distribution was classed as being a northern species most commonly found in Scotland and the map showed Herefordshire as being the closest county to have a record with a scattering of records in northern England. So had we found a first for Wales?!?! A quick email to Montgomeryshire County Moth Recorder, Peter Williams, revealed that it is certainly a Denisia similella the first for North Wales and almost certainly a first for Wales!!!! Just goes to show what is still to be found, you've just got to look!
An unlikely birding highlight this week was a group of 7 Collared Doves in the village of Abertridwr which are annual but for some reason rarely seen. The pair of Great Crested Grebes have built a new nest at the top of the lake and a Little Grebe has also been seen feeding from the Lakeside hide.
Plant of the Week
Himalayan Balsam / Ffromlys chwarennog (Impatiens glandulifera) (Photo by Gavin Chambers)
Himalayan Balsam was introduced to the UK in 1839 and is now found across the majority of the country. It is commonly found along riverbanks and in wastelands where it has become a very problematic weed. It does not require much light to grow and once fully grown it can reach heights of 2-3m and smother other plants of light and nutrients which eventually kills them off.
In late summer it produces clusters of purplish pink flowers, helmet-shaped. These are then followed by seed pods which is where the problems start. Each plant can produce up to 800 seeds and it has a coiled spring mechanism, which can fire seedpods up to 7m away once ripe and mean a rapid spread. To add to this seeds can stay viable for 2 years and due to their typical riverbank location, the seeds can be transported downstream and deposited on a new bank to start a new colony.
This week we have started to remove as much Balsam as quickly as possible before they start seeding. Our method, which is the best non-chemical method of control, is to pull the individual plants out. This works because it is an annual plant, meaning it only lives for a single summer then dies and will only grow back from seed.
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