The bird survey season has now in general come to an end with most birds having now fledged and started to wander further afield. Birds such as pied flycatcher seem to completely disappear once the chicks leave the nest though this is mainly due to their habit of moving into the tree tops to feed making them difficult to spot. However, redstarts are a bit showier and can be spotted by their flicking red tail as they dart from tree to tree often in open habitats such as the walk up to the waterfall along the green trail.
Pied flycatchers (female left, recently fledged right) - archive image by Gavin Chambers
You may have noticed that we are experiencing a bit of a heat wave, though it does slightly depend on where in the country you are. We have experienced the high 20’s in temperature with the occasional damp day but it is clear from the water level in the lake that there’s not been much rain at all. Lower water levels at the top end of the lake can attract more birds since more mud is exposed for birds to feed in. So far there have been 5 common sandpiper, pied wagtail, grey wagtail and 27 Canada geese in the area. A couple of little grebes have also been feeding on the lake seen from the Lakeside Hide.
With current water levels there is a good chance of the odd wader dropping in as they migrate through the country. We have had green sandpiper, whimbrel, redshank, lapwing and oystercatcher in recent years.
One of the last surveys to be completed is our annual Welsh clearwing moth survey to establish the current habitat condition and presence of breeding individuals. They have a very particular requirement to breed which is essentially an old birch tree with a girth (circumference) of 100cm and have at least half the lower 2m of the trunk unobscured from the sun/sky.
Welsh clearwing exuvia/casing emerging from birch tree by Gavin Chambers
In the last couple of years we have failed to find any positive signs of breeding, but thankfully this year I discovered a single tree with 9 exuvia protruding from the bark. These are the casings left behind after the caterpillar emerges as the adult moth. The caterpillar feeds under the bark of the birch tree for two or three years before pupating and then emerging as an adult through the bark to leave distinctive exit holes about 5mm wide. Despite its name the Welsh clearwing can also be found in Scotland and England, but it was first discovered near Llangollen in 1854.
Denisia similella by Gavin Chambers
Three years ago we found what we considered to be the first for Wales (see here), a small micro moth Denisia similella, which we now refer to as ‘Dennis’. Well, while surveying, I suddenly noticed a small moth on my survey sheet and thought – I recognize you! It was Dennis, or at least one of its great grandmoths, which is probably the 2nd record for Wales!
Gavin Chambers, Warden
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