Lake Vyrnwy

Lake Vyrnwy

Lake Vyrnwy
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Lake Vyrnwy

  • 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

  • All about Ffridd

    The past week has been dominated by ffridd surveys. But what is ffridd? Well, ffridd is the Welsh name used to describe the habitat margin between the lowlands of good grazing and the moorland. It is generally slopes dominated with bracken with scattered trees and potentially scattered gorse and heather. Due to its nature of being the margin between two habitats it can be very variable and consist of different vegetation types and density depending on location and any management taking place, typically grazing.

    Lake Vyrnwy ffridd in March by Gavin Chambers

    Ffridd can support a good range of species including whinchat, ring ouzel, tree pipit, fritillary butterflies and ivy-leaved bellflower, all of which we get on the reserve. Given the three bird species mentioned are all Red Listed it highlights the importance of this habitat. So bird surveys taking place this year are aimed at understanding what our current population levels are on ffridd and can be used in the future to see how management that will take place in these areas has affected bird numbers.

    Male whinchat on ffridd by Gavin Chambers

    Good places to see ffridd and its associated species are along the Dinas Mawddwy road and Bala road by bridge over river.

    Recent Sightings

    With the arrival of some warmer weather the final summer migrants have arrived back. This includes whitethroat, garden warbler, spotted flycatcher and swift screaming over the village. Insects have been more noticeable with the first green hairstreak seen on the moors, green tiger beetle and some interesting looking nomad bees which look a lot like wasps!

    Nomad bee by Gavin Chambers

    Other highlights have been an adult hobby low over the village on 12 May and an osprey circling high over the Dinas Mawddwy road on 13 May.

    Adult hobby over Llanwddyn by Gavin Chambers

    Previous Blog: Expect the unexpected!