In like a Lion, out like a Lamb

In March, the surveying season starts. And when it starts, it starts with a bang.

After weeks of inaction due to Covid restrictions, the second week of March has been filled with the resumption of surveys of all types.

First off was Sunday morning, 14th March, surveying Maer Lake for the BTO’s Wetland Birds Survey. There were a limited number of bird species, although there was an unprecedented mixed flock of over 300 gulls, as most of the winter waders had left although a pair of Shelduck remained giving hopes of another breeding year. Black-tailed Godwits were also noted; they seem to be residents now.

This was quickly followed the next day by a visit to Tamar Lakes, again WeBS at Lower and Upper Lakes. This was similar to Maer with few winter visitors although the annual Goosander visitation had not come to an end with four remaining on the Lower and two on the Upper Lake.

Mixed flock of Gulls at Maer Lake

The temperature was around 13℃ so high enough to commence the Bee walk in Coombe woods. Although not many were seen, we did find that where Willows were in flower, they had attracted quite a few Buff-tailed Bumblebee queens high up in the canopy.

Thursday 18th was the day we planned the quarterly bird transect around Bude Marshes. Normally this is a group effort, but to conform with Covid regulations, Duncan and I have been the only two participants for a year now. Numbers of species are definitely down; from 31 last March to only 24 this year although it did include Shelduck, Curlew and two Cattle Egret.

Cattle Egret - Bude Marshes

During the month, the invertebrates had begun to appear from their winter absence. Gorse Shieldbugs, 7-spot Ladybirds and Buff-tailed Bumble bees were appearing at the beginning of the month in that short warm spell.

We had the very cold and windy middle of the month, typical of March until the last week when we had the mini heatwave. Butterflies - Small Tortoiseshell and Brimstone, and those harbingers of spring, Skylarks and House Martins.

During this cold spell, I completed my three Riverfly surveys adding another beetle to my growing species list - Oreodytes sanmarkii, a tiny 2-3mm water beetle that zooms about in the water column of stony streams.

2-3mm Water Beetle - Oreodytes sanmarkii

The 30th was a very warm day, hitting 18℃ when I recommenced my Butterfly Transect along the Tidna. Although there were only four butterflies of three species - Speckled Wood, Peacock and Small Tortoiseshell, other invertebrates were recorded. Common Carder and Red-tailed joined the Buff-tailed Bumblebees along with more Gorse Shieldbugs and 7-spot Ladybirds.

Of great interest were the Oil Beetles. I recorded both Violet Meloe violaceus and Black M. proscarabaeus in the Tidna Valley as well as the triungulins of the Violet species. These are bee parasites. The adults lay eggs in sandy soil near a bee nest . These in turn hatch into triungulins (so called because they have three claws on each leg)which emerge and crawl onto flower heads and lie in wait for a passing bee. They hitch a ride into the bee’s nest where they eat the bee’s eggs before changing into grubs where they remain until emerging as adults the following year. The cycle then repeats.

Clockwise - Violet Oil beetle, triungulins, Black Oil beetle

On the last day of the month another butterfly, a Red Admiral was recorded along with the first Green Shieldbug of the year.

To top it all off, life has continued to develop in my Lockdown Pond. I built it during Lockdown1 from 8th April and filled it with water on the 16th. At the begining of March, I found a Palmate Newt under a log and transfered her into the pond where she vanished into the bottom mud.

Palmate Newt

 In the last few days of the month I have seen, a Backswimmer (Notonecta), Pond skaters (Gerridae), a Whirligig beetle (Gyrinus) and three Dragonfly nymphs. As I noted ovipositing Broad-Bodied Chasers last May, these would appear to be its progeny.

Broad-bodied Chaser nymph

Those last few days of March were gentle, warm and windless - almost as gentle as the large numbers of new-born lambs in the fields.

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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.