Lake Vyrnwy

Lake Vyrnwy

Lake Vyrnwy
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Lake Vyrnwy

  • Lake Fernwy

    In our recent RSPB magazine, Natures Home, it stated that 16,000 species have been found on RSPB reserves across the UK. It then breaks it down to the top 10 reserves and also the reserve with the most species of a certain taxonomic group (birds, dragonflies etc.). Lake Vyrnwy turns out to be the RSPB reserve with the most ferns, with 22 species, which I immediately saw as a challenge!

    Given my limited knowledge of ferns I thought it would be a good summer/autumn project to learn how to identify ferns while at the same time trying to find as many of the 22 species as I could. There are only 64 species found in the UK with many of these being fairly distinct which meant I could get off to a quick start without too much head scratching.

    Probably the easiest species, which I would suspect the majority of you reading this will have already seen, is bracken. To be honest it hadn’t crossed my mind that it was a fern but having now studied all ferns it quite clearly exhibits fern characteristics.

    Wall rue (left) and maidenhair spleenwort (right) on office wall - by Gavin Chambers

    Old mortared walls are a good place to look for ferns with a few limestone species liking the lime mortar. Around the shop/office I found maidenhair spleenwort, wall rue, and hart’s tongue. The local graveyard wall has in the past been known for its ferns and from what I have found it still is, with some nice species such as: rustyback, black spleenwort and brittle bladder fern (my latest find). Another rocky species, though not requiring limestone, is the parsley fern which as its name suggests looks a little bit like parsley.

    Parsley fern likes rocky screes - by Gavin Chambers

    Identification gets a little trickier when looking at woodland species, especially the ‘shuttlecock-shaped’ species. So far I have identified male, lady, broad-buckler and lemon-scented fern along with the scaly male fern, but this is split into three species which I am yet to fully understand. Other woodland species found are beech, oak and hard fern as well as common polypody which is often found growing on tree branches and trunks.

    Lemon-scented fern which has a citrus smell when young - by Gavin Chambers

    Perhaps the trickiest species that I have found is the wilson’s filmy fern which is one of the smallest ferns and grows over damp rock, often in the splash zone of running water. Fortunately I had a rough idea where it had been found and after a couple of visits to the area found three rock faces which had it growing. It wasn’t at its best given the recent drought but it was good to see it was still present.

    Wilson's filmy fern, curled up due to dryness - by Gavin Chambers

    So I have currently found 18 of the 22 species on the reserve in around 2 months of searching. Two of the four remaining ferns are tricky to separate and will require more studying and a third species, the narrow-buckler fern, I may have found but it hasn’t completely unfurled yet so will have to go back for another look.

    Previous Blog: Mimics and Migrants

  • Mimics and Migrants

    In the last month we have enjoyed some nice warm sunny weather which has given the many invertebrates, from moths to hoverflies, a chance to emerge and not forgetting the midges! This has been great for the breeding birds as they relentlessly forage for food for their hungry chicks including the newly fledged pied wagtail chicks outside the volunteer accommodation.

    Pied wagtail chicks waiting to be fed outside volunteer accommodation – by Gavin Chambers

    Given invertebrates are the prey item for so many predators, such as birds and other invertebrates, some have come up with ways of reducing their chance becoming breakfast. The hoverfly volucella bombylans (photo below) is one of the better mimics which looks a lot like bumblebee species, and amazingly has more than one colour form as shown in photo below. Incredibly this species lays its eggs in the nest of bumblebees which makes you wonder if the bumblebees themselves are fooled by the mimicry? However, it is generally thought that mimics look like bumblebees and/or wasps to make them look noxious (i.e. distasteful and likely to have a sting) to put predators off eating them.

    Volucella bombylans (hoverfly) at Lake Vyrnwy – by Gavin Chambers

    Moths are also good at mimicry to try and avoid predation. In general they use camouflage to blend into their typical habitat such as the buff-tip which looks a lot like a birch twig. Others will use bold flashes of colour to warn off predators with a few species having the larges ‘eyes’ as seen on the peacock butterfly.

    Buff-tip – by Gavin Chambers

    Despite their size invertebrates can travel very long distances, using weather systems to blow them to a new location. Species such as the painted lady butterfly and humming-bird hawk-moth are well known for their movements from Africa and the Mediterranean. However, this year has seen a mass movement of a tiny moth, plutella xylostella (diamond-back moth), with a wingspan of only 15mm. It is thought that millions have arrived from Continental Europe though we have only had a maximum of 7 in the moth trap.

    Plutella xylostella (Diamond-back moth) – Archive photo by Gavin Chambers


    Previous blog: Bank Holiday Stroll

  • Bank Holiday Stroll

    The prospect of a sunny Bank Holiday had me off to the top of the lake and a wander along the Green Trail to see what was around. Drop in to our shop and visitor centre to collect a trail guide to all our trails and find out the latest information before going out to explore the reserve.

    My first sighting was of Tom, an ex-intern from a couple of years ago who had popped over for the day, which may have been the biggest surprise of the day! After a quick chat it was back to the real wildlife with singing redstart around the car park and a distant view of a spotted flycatcher. Along the stream both a grey and pied wagtail were bouncing along the rocks only as a wagtail can, tail going like a metronome.

    Pied wagtail below waterfall by Gavin Chambers

    Looking skyward the local pair of peregrine were hanging in the strong wind and a couple of raven soared over with their distinctive deep croaking call. Another redstart decided to really show off and sit proud at the top of a tree and burst out its song while clinging on as it swayed in the wind.

    Male redstart singing along Green Trail by Gavin Chambers

    The woodland section of the trail started with a distant cuckoo calling and a male pied flycatcher keeping guard around its nest box. Unlike the pied flycatcher a singing blackcap made itself extremely difficult to find despite sounding very close and a spotted flycatcher sang directly above in a dead tree.

    Common sandpiper below dam by Gavin Chambers

    A walk to the Centenary Hide produced an energetically singing garden warbler which showed very briefly and a newly fledged grey wagtail chick. Walking back to the car park a dipper gave a burst of song and a common sandpiper floated downstream, they have also recently been seen feeding along the dam wall.


    Previous Blog: All about Ffridd