Lake Vyrnwy

Lake Vyrnwy

Lake Vyrnwy
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Lake Vyrnwy

  • Batman and a Great White!

    It is that time of year when birds start to move, those that joined us to breed in the summer are now heading back south for the winter and those that headed north to breed and starting to head back. There are also birds that generally disperse, especially juveniles, in all directions and could turn up anywhere.

    Here at Lake Vyrnwy our location is not ideal for attracting these migraters as the majority will use the coastline. However we did get a rather elegant Great White Egret which was first spotted on 7th August and stayed for just over a week (15th August) at the top end of the lake viewable from the Lakeside Hide. Photos of the bird can be seen on the Montgomeryshire Bird Blog.

    Great White Egret at Lake Vyrnwy in May 2014 (Photo by Gavin Chambers)

    Above is a photo of the bird that we had in May 2014 which was an adult in breeding plumage, whereas this years bird is in immature or non-breeding plumage. Though I did see the bird last year I managed to pick the wrong week to have a holiday!! Despite arriving back on the 16th the bird had done a ‘runner’. I did however find a single Teal, my first of the summer, and a nice flock of 4 male Common Scoters which keeps my run of scoters going having now seen 104 Common Scoters (and a Surf Scoter) over three summers.

    In the woods the summer migrants are now gone with the resident birds starting to flock together. You can typically find Long-tailed, Blue, Great, Coal and occasionally Marsh Tits moving through the trees together with the odd Willow Warbler, Chiffchaff or Treecreeper mixed in. Juvenile birds are also on show with young Bullfinch and Redpoll seen recently from the Centenary Hide, plus a glimpse of a Kingfisher on the 23rd.

    Juvenile Bullfinch from Centenary Hide (Photo by Gavin Chambers)

    You may think the blogs title suggests a story about bats, but in fact it is actually to do with Hoverflies! I have recently become very interested (OK obsessed!) with finding hoverflies and one of the first ones I found to be reasonably easy to identify was one that showed a ‘Batman’ symbol on its thorax.

    Myathropa florea at Lake Vyrnwy (Photo by Gavin Chambers)

    An interesting fact about hoverflies is that you can tell a male from a female by looking at their eyes (for the majority of species). If their eyes meet at the top it’s a male and if there’s a gap it’s a female. So the photo above is of a female Myathropa florea and can you spot the Batman mark?

    Chyrsotoxum arcuatum at Lake Vyrnwy (Photo by Gavin Chambers)

    A number of hoverfly species go for the mimicry tactic to put predators off and my latest find is typical of this. The above Chyrsotoxum arcuatum has a very Wasp-like pattern and takes me to around 35 species that I have found and had ID confirmed by experts on Facebook.

    Plant of the (last few) Weeks

    Broad-leaved Helleborine / Caldrist Llydanddail (Epipactis helleborine) (Photo by Gavin Chambers)

    A nice find by Gethin while heading out to pull Himalayan Balsam..... yes we are still attacking the Balsam!

  • A First for Wales?

    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.

    Previous Blog: Blue Dragons!

  • Blue Dragons!

    Though we a situated in the heartland of the Red Dragon, it has been the Blue Dragons that have been most prominent these last couple of weeks. The soaring temperature, reaching around 25°C, gave dragonflies and butterflies the chance to warm up and emerge from their nymphs and chrysalises.

    So one sunny afternoon I decided to get the weekly Butterfly Transect done which, with the temperature at 23°C, promised great things. The first few sectors were very quiet with only a Large Skipper and Meadow Brown being recorded and moths in the form of Beautiful Carpet, Wood Tiger and Clouded Buff being nice additions.

    Wood Tiger along Butterfly Transect (Photo by Gavin Chambers)

    The end of the transect picked up with a good variety of Butterfly seen but not really in the numbers you might expect in the conditions. A nice patch of Forget-me-knot had attracted a Green Hairstreak and a rather worn Common Blue which isn’t as common at Lake Vyrnwy as its name suggests. Other species seen were: Ringlet, Small Copper, Small Pearl-bordered Fritillary, Green-veined White, Small Tortoiseshell and Small Heath. So 11 species recorded but only 14 individuals in total perhaps suggesting the cold spring in to summer has affected them or there are still many more to emerge.

    Male Broad-bodied Chaser at Lake Vyrnwy (Photo by Gavin Chambers)

    So the Blue Dragons.... at the end of the transect there is a small dammed pool with small stream running in and out of it. It is great for Dragonflies and Damselflies and this was certainly true in the blazing sunshine. The usual suspects were around: Common Blue, Azure, Blue-tailed and Large Red Damselflies and Four-spotted Chasers. There was then a few flashes of chalk blue zipping around the edge of the pool, the largest one was fairly easy to get an ID of – a stunning male Broad-bodied Chaser.

    Male Black-tailed Skimmer, a first for Lake Vyrnwy (Photo by Gavin Chambers)

    The other blue flash was smaller and thinner bodied, so would have to be a male Keeled Skimmer or Black-tailed Skimmer. However Black-tailed Skimmers like pools whereas Keeled Skimmers prefer small running ditches and damp areas. It was soon joined by a female which, after the male had sat for a photograph, also helped confirm ID as a pair of Black-tailed Skimmers. It later transpired that this was the first record of this species at RSPB Lake Vyrnwy!

    Beautiful Demoiselle at Lake Vyrnwy (Photo by Gavin Chambers)

    The final species was a real beauty, a stunning iridescent Beautiful Demoiselle which unlike its close relative, the Banded Demoiselle, prefers running streams to slow moving water.

    On the bird front, the summer migrants are starting to disappear from the woodlands. However a summer migrant was heard for the first time this year - a Quail. This tiny gamebird which is recorded here most years has a very distinctive call/song which is said to sound like 'wet-my-lips' which you can listen to here. A Kingfisher has also been seen off the dam, as were a group of 9 Common Sandpipers roosting on the shoreline and are probably a group on migration south.

    Plant of the Week

    Greater Butterfly Orchid / Tegeirian llydanwyrdd (Platanthera chlorantha) (Photo by Gethin Elias)

    Last week Gethin Elias re-discovered this plant growing on the reserve it hasn’t been recorded since 1986.

    An orchid of hay meadows and grassland it can be found along rides, clearings and edges of woodland. Due to the massive decline in meadows in the country this orchid is struggling to survive and has unsurprisingly greatly dropped in numbers.

    A single spiked plant up to 60cm in height, it has several whitish to green flowers each with spread sepals and petals. The flowers lowest petal is yellowish green and long and narrow with its leaves being spotless, broad, shiny and elliptical. Care should be taken to separate the Greater Butterfly Orchid with its close relation the Lesser Butterfly Orchid, you need to examine the pollinia (mass of pollen)!

    Previous Blog: Future Secured!