Lockdown Pond

During lockdown, I fulfilled a long-standing ambition and built a pond.  I'd been promising myself that I would do this for years, but never got around to it. During April I bit the bullet and made a start.  

The result is a modest affair, 3m x 2m with a maximum depth of 0.4m in a very flat grassy garden bordered by fields.  

Lockdown Pond

I added water on 16th April and within a matter of hours, it had attracted three different species of water beetle.  Within this short space of time, there were around 50 tiny 2-3mm Helophorus, four medium-sized Hydroporinae and a couple of larger Dysticidae.  On the 19th a Pond-skater (Gerridae) visited briefly, but did not stay.  The Helophorus mass-attacked anything organic that fell into the water and the Helophorus could be heard hitting the plastic liner where they immediately started mating furiously.

Left Dytiscidae and a mass of voracious Helophorus demolishing a slug

Hydroporinae

The birds like it. All species seen in the garden have used the pond to drink or bathe with a blackbird seen gathering damp mud to line her nest and once a couple of swallows skimmed low but did not stop to drink.  Birds seem to gather near it, frequently settling comfortably in the grass.

I wanted the pond to colonise naturally, which it is doing for the fauna, but I admit to helping the flora.  I have replanted a couple of  Common Rush Juncus effusus and Water mint Mentha aquatica at the bog end of the pond and acquired three Common Spike Rush Eleocharis palustris plants which I planted in the shallow water's edge, and I've also added a small piece of Common Water Moss Fontinalis antipyretica.

The last couple of weeks have been challenging through lack of rainfall.  I could almost watch the water level falling as the contents of the pond evaporated.  Last week, I emptied the last 75 litres out of my water butt but still the level continued to fall.  I have joined the Wildlife Ponds UK  Facebook group 

https://www.facebook.com/groups/2122154031407805/ and looked there for advice.  The recommended strategy was to use tap water but fill the pond through a spray nozzle to help remove the Chlorine from the tap water.

This morning (28th May) I sprayed the pond and raised the level by a couple of inches, a much more acceptable depth.  Once done, I contemplated my satisfyingly deeper pond and spotted another new arrival.

Lesser Diving Beetle - Acilius sulcatus

This was a much larger and very busy water beetle.  It was about the size of a thumb-nail with yellow horizontal markings across its head and broad grey stripes along the elytra - a Lessser Diving beetle, Acilius sulcatus!

As if this was not enough, an hour or so later, two female Broad-bodied Chasers Libellula depressa had found the pond and were ovipositing in it.

Broad-bodied Chaser - Libellula depressa

Never mind the South West Water bill, I'll have to keep topping up the water level to ensure the survival of their nymphs.

Shark! Shark!

Friday night is the night chosen for co-ordinated moth trapping for those who submit their records to the Garden Moths Scheme (GMS).  This gives a nation-wide comparison of the diversity and abundance of moths throughout the year.  This week, (22nd May) was unseasonably windy, which is not the best weather to catch moths, and continued the same through Saturday.  So, I delayed my GMS until Sunday night when the weather was expected to improve.

I was not disappointed.  The wind had dropped and there were no clouds.  This meant that it was not very warm overnight, but with a minimum of 7℃ it was not too cold for moths.

My trap is a Skinner design 20 Watt twin blue light bulb type.  As such, it will never attract the multitude of moths that a Robinson trap with Mercury Vapour bulb does.  Over Sunday night, it did not do too badly attracting 26 moths of 11 species.

The largest number of  a single species trapped, was eleven Heart and Dart - named somewhat imaginatively for the two dark marks on each wing of a dart shaped mark above a heart shaped mark.

Heart and Dart 

Next in number came four of the prosaically-named Treble Lines, named for the three horizontal lines across both wings.

Treble Lines

Apart from three Flame-shoulder (not illustrated) the remainder of the moths were all single records.  Moving away from the predominantly brown moths, there was a very attractively marked, and appropriately named, Broad-barred White  

Broad-barred White

Other single specimens were Pale Tussock, Common Pug, Brimstone and Flame.  The final three were huge moths.  Those who visit Lundy or walk the North Cornwall cliffs may be familiar with the large, brown, hairy caterpillars that feature there for most of the year.  These are the caterpillars of the Fox Moth, but the moth itself is more elusive.  It is a big moth with 34mm long wings and has a large fat body and similar colouring to a Fox.

Fox Moth

Another large 34mm long moth is the aptly-named Great Prominent.  As well as having big wings and a large body it has heavy hairy legs.

Great Prominent

Finally, a slightly smaller moth around 30mm in length but much slimmer and more streamlined.  This is  a grey finely marked moth - the Shark.  It is so named because of the prominent crest projecting over the head of the moth resembling the fin of a Shark.  It was not Jaws, but a shark in the garden is a most unexpected first for me.

The Shark

Of course, it being May, there were three of the almost obligatory large Maybugs or Cockchafers.

Weather wise?

After the fabulous weather that brought all the butterflies out, I was not sure that the last couple of days would come anywhere near that.

Yesterday it was so hot that we shortened out usual walk.  We did not see many invertebrates at all but were very pleased to see this newly hatched batch of Garden spiderlings Araneus diadematus</.  They can easily be dismissed as a flower head until tickled with a piece of grass when they disperse symetrically from the centre.

Garden spiderlings - Araneus diadematus

Today (22nd) was even less promising with quite a strong wind and overcast.  Nevertheless we completed out usual walk and were delighted to find new invertebrates along our normal route.

A Blood-vein moth Timandra comea was sheltering deep in the roadside vegetation and made no move while I took an extreme clos-up.

Blood-vein Moth - Timandra comae

Similarly, slightly further on,we spotted a Leaf beetle of the Chrysomelidae species.

And, just to round things off, a Wasp mimic Longhorn beetle Clytus areitis was found clinging on tightly to Hemlock Water Dropwort alongside the road near Stanbury Cross.  It is harmless without a sting, but uses its wasp-like colouring to deter predators

There is always something to be seen no matter the weather.

UNLOCK!

No, it's not the sound of Mr Speaker, Sir Lyndsay Hoyle MP, announcing the end of a division in the House of Commons.  It is what has happened over the last week in the surveying world.
British Trust for Ornithology were the first to announce the lifting of surveying restrictions which had been in place since late March.  They were followed by Riverfly and UKBMS.  All them caveated the lifting of surveying restrictions with government advice on social distancing and a maximum of two people surveying.

I must admit to slightly preempting the Riverfly announcement by surveying my Tidna site on 14th May.  Water levels were falling and I didn't want to risk missing the opportunity to survey while there was still some water flowing in the stream.  Despite my misgivings, there was an abundance of invertebrates in the stream giving an abundance score of 12, 4 over the trigger level with Baetidae contributing an abundance score of 3 with over 250 individuals counted.

My Riverfly survey site on the Tidna - May 2020

On Sunday 17th I completed my first WeBS (Wetland Birds Survey) since March at Maer Lake.  Water was in very short supply here with this seasonal lake drying rapidly. 

Maer Lake drying out May 17th 2020

The lack of water and time of year limited the number of birds seen, but I was able to add Mute Swan and Whitethroat to my personal species list for this site as well as seeing a pair of Shelduck.  These bred last year, so with a little luck, and some rain, we may see more Shelduck chicks this year.

Maer Lake - Mallard, Mute Swan, Moorhen and Black-tailed Godwit.

Maer Lake - a pair of Shelduck

I followed this with my survey of Lower and Upper Tamar lakes on Monday 18th.  Again, water levels and species diversity was down.  But Mallard and Canada Geese have bred and young were seen as well as the spring migrants such as Chiffchaff and Willow and Sedge Warblers.

Canada Geese and Goslings at Upper Tamar Lake

Sedge Warbler at Upper Tamar Lake

All these synchronised BTO WeBS surveys were one week later than previously planned due to the length of the lockdown.

My most recent survey was today, the 20th, probably the hottest day of the year and ideal for my butterfly transect unlocked and now made possible by  UKBMS (United Kingdom Butterfly Monitoring Scheme).  This is normally a weekly survey which I last undertook during the last week of March.  What an excellent survey, 73 butterflies of 12 species - Large Skipper; Brimstone; Large, Small and Green-veined Whites; Orange Tip; Green Hairstreak; Small Copper; Common Blue; Small Pearl-bordered Fritillary; Speckled Wood and Small Heath.  What a wonderful range of species.

Green Hairstreak Tidna Valley

Small Heath Tidna Valley

Small Pearl-bordered Fritillary Tidna Valley

Common Blue Tidna Valley

I plan to complete my monthly suite of surveys with my two other Riverfly surveys in Coombe Valley and Duckpool/Stowe Woods Bee Walk (although this latter has only just been authorised by Bee Conservation Trust).
It the weather continues as it looks to be, sunny and dry, it is looking like and excellent year for invertebrates now we are unlocked.