Bean Geese and Ping pong bats

I don't know whether it is just luck or that spring has come to North Cornwall, but we are extremely fortunate in the two species new to me and quite unusual.

On Monday, 7th February, we decided to take one of our regular walks around Upper Tamar Lake.  We had heard that there were some rare Geese seen in the previous week. Although we had not expected them to still be around, we did look for them anomgst the large flock of Canada Geese on the fields bordering the western (Cornwall) side of the lake.

We were in luck!  Around 200 Canada Geese were grazing on the open field with three Tundra Bean Geese on the edge of the flock.  Even better, they were not too close to take flight nor too far to be photographed.

So, one species new to us - a major "tick" Anser serrirostris.

Two Tundra Bean Geese amongst Canada Geese

A resting Anser serrirostris.

Today, 10th February, was my day for Riverfly - surveying my local stream, the Tidna for freshwater invertebrates.  The stream is found in a deep Cornish wooded valley about 200 feet down a set of steps to the valley bottom.  

Once the survey is complete, it is a slow climb back up stopping occassionaly to catch my breath.  About halfway up I spotted a dead branch beside the steps with an interesting row of tiny orange fungi growing along it.  I stopped to examine them and was surprised to recognise a fungus previously seen on Lundy.

They were Orange Ping Pong bat fungi, an invasive species only recently found in the UK and spreading around Cornwall and Devon.

The cap is only around 7mm in diameter (the picture shows a ruler with 1mm divisions) but the underside is distinctive and diagnostic.

Although invasive, it is no threat to the flora of the UK in that they decay dead and dying timber only.

The rest and the find gave me a spring in my step and the remaining steps did not slow me at all.

What a find two rare species in one week!

Orange Ping Pong Bat fungus underside

Favolaschia calocera - 7mm cap

 

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.

Blogs I follow

https://downgatebatman.blogspot.com/

https://maryatkinsonwildonline.blogspot.com/

Grisly nature

Folklore had these parasitoid worms forming from the dropped hairs of horses when they were frequently found in horse troughs.

The Gordian knot is an illustration of a problem without a solution. An ox-cart which delivered a peasant named Gordias into Phrygia who became its king, was tied up with a knot so intricate that is was not possible to undo it, but whoever did would rule the whole of Asia  Alexander the Great tried and failed so sliced it in half with a stroke of his sword hence the Gordian knot/

A phylum of parasitoid invertebrates comprising the marine Nectonema and freshwater Gordioida. There are 350 different known species throughout the world.

Adults can reach a length of between  50 and 100mm and in extreme cases 2m but only up to 1mm in diameter.

They have an external dark brown cuticle, which is almost all muscle which gives them a hard and wiry feel. This muscle arrangement results in them  twisting into intricate knots - hence the genus name Gordius resembling the classical Gordian Knot. 

Nematomorpha showing the eponymous knotting behaviou

They lack any excretory, respiratory or circulatory system.  The eyeless head may have a darker band below the paler tip.

The tail end of females is rounded but males of most genera genital papillae showing as a cleft tail.  Males of Gordius genus have a crescent-shaped fold above the two lobes.

Male nematomorpha with bifuricated anterior.

They exist in their external adult form purely to reproduce.

The life cycle is complex and almost wholly parasitic.

Long strings of gelatinous eggs are laid in freshwater.

From these develop planktonic larvae which have a boring apparatus with which to enter its first host, aquatic invertebrates typically diptera or trichoptera larvae.  Once inside this host, they encyst in the gut of the invertebrate.

In turn, these invertebrates are predated upon by freshwater or terrestrial invertebrates, typically Coleoptera or Orthoptera with Carabidae being a common host.

Once inside this host, the larvae develop into the adult worm-like form.  They grow to fill the internal cavity of the host but also influence it to seek out and enter water where the host drowns.  Once this is achieved, the adult Nematomorpha will abandon the host and seek a mate to reproduce in freshwater where the next season’s eggs are laid and the adults die.

 The National Biodiversity Network shows 251 records, the majority of which were recorded in Wales and a few in Scotland.  The South West has no records at present.  However over the last three years specimens have been increasingly recorded in Cornwall and on Lundy. 

Although reportedly adults emerge from their host in late summer or early autumn, on Lundy adults are typically found in shallow temporary puddles on the island road in November and December.  In Cornwall, they have been recorded during Riverfly surveys in small streams in April, August, September and November.

I always search shallow puddles of the picture that eludes me, that of an adult emerging from its host.

Blogs I follow

https://downgatebatman.blogspot.com/

https://maryatkinsonwildonline.blogspot.com/

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.

A Wonderful Wildlife Week

Every now and then there is a week that is day after day of natural history. 


This last week was just such a one. There was an event planned for every day and the weather was kind.

Great Crested Grebe on her nest

Monday The monthly BTO Wetland Bird Survey was due, and as usual we deferred it for a day to avoid the busy weekend at Tamar Lakes. It is April so the winter visitors had gone and there was only a chance of spring or summer visitors being present. We did hear a single Sedge Warbler staking out his territory and spotted a Great Crested Grebe sitting on a newly constructed nest. There was also one or two Chiffchaffs, Willow Warblers and a lone Swallow.

Peacock butterfly

After lunch the weather was warm and sunny with hardly any wind. It was the ideal time to walk our newly registered UKBMS butterfly transect. This starts at the Bush Inn at Crosstown in Morwenstow, descends to the Tidna Valley and follows the river to the coast then up the cliff before heading inland along a green lane to Crosstown Green. It was a good decision with butterflies of four species – Speckled Wood, Small Tortoiseshell, Comma and Peacock.

Sunset over the south end of Lundy

Tuesday We had an early start, leaving Bideford quay at 9am for Lundy. The sea was like a mill pond but we saw no cetaceans and few birds. The island was alive with spring birds though – Willow Warblers, Chiffchaffs and Blackcaps. I spotted a Sparrowhawk at Quarter Wall Pond after a long meeting inside. The return trip was spectacular with a brilliant orange sunset over the island as we returned at 7pm.

Piscicola geometra

Wednesday The first Riverfly survey of the year on the Torridge near Bradford Mill and the first since the July 2015 was planned. In August and September last year, the river was in spate and two metres higher than normal. In the event, the river was slightly higher and faster than normal, but it turned up plenty of invertebrates. It was interesting to record the difference in abundance of the eight indicator species. Stoneflies were particularly abundant with a few extremely large specimens almost ready to become flying insects. The normal Perlodidae were joined by two specimens of Taeniopterygidae. Another unusual species, not part of the survey set, was a fish leech, Piscicola geometra.

Planting Marram Grass

Thursday This was a Bude Valley Volunteers working party day. Following the “planting” of retired Christmas Trees after 12^th night in January at Widemouth Bay the plan was to supplement this with the planting of Marram Grass. The trees were already doing their job of accumulating sand around themselves. We were allowed to dig up randomly selected Marram plants and transplant them between two rows of the trees. The expectation is that the Marram will further stabilise the sand allowing and embryo dune to form.

 This will in future plug a gap where the dunes had “blown out” and reduce the chance of sand blowing onto the adjacent coast road.

Picnic at Dexbeer Bridge

Friday The culmination of a busy week – to walk the whole length of Bude Aqueduct. Four of us started from Lower Tamar Lake and walked the whole 5 miles to Vealand Reserve where we then followed the permissive path for a final 700 yards. The weather was again kind allowing us to have our first picnic of the year at Dexbeer Bridge on Councillors Shadrick's memorial table. We shared the area with a pair of Willow tits – confirmed as they responded strongly with identical calls to those Willow Tit lure. We recorded a total of 34 species of birds on our walk including all 5 tits – Great, Blue, Coal, Long-tailed, Marsh and Willow and 4 finches – Gold, Green, Chaff and Bull. We also noted 4 spring plants – Wood Anenome, Wood Sorrel, Cuckoo flower and Lesser Periwinkle together with all 3 mammals so far seen on this walk – Roe Deer, Grey Squirrel and Rabbit.

The only let down was Friday night's Garden Moth Survey which due to the cold and wet attracted not a single moth.

Riverfly - Riverflow

Torridge in flood - note the line of
vegetation showing the submerged bank

Today was our last attempt at the August Riverfly survey.  A friend and I volunteer to survey 8 species of invertebrates in the River Torridge near Bradford Mill.  This takes place once a month between April and September.  We usually plan to survey mid-month so as to allow us an alternative date, if the weather is too bad, later in the month.

Last week the it rained heavily all of the day we had planned to survey so we postponed until our alternative on the 26th August.  I drove across the Tamar to get to the site and noted flooded fields either side of the border on the Holsworthy road which did not bode well.

Surveying on the lower river bank

Nonetheless, Barrie and I set out to our survey site which is half an hour walk from where we park the car at Bradford Church. It was wet and heavy going towards the last field where the river flows.  Going through the final wet and muddy gateway we could see what is usually a strip of Juncus in a damp hollow had become a deep tributary to the Torridge. This was too deep to pass, so we walked parallel with it to where it flowed into the main river.

What a deep raging torrent! We could see the tips of Himalayan Balsam that group on top of the river bank just breaking the flood. Our survey site was under 2 meters of fast flowing turbid water carrying large branches along with the flood.

Small Copper 

Discretion took over, a couple of pictures and we trudged back home. No chance of the waters subsiding before the end of the month meant a nil return for August. It will be interested to see how quickly the invertebrates re-colonise the river after this flood event.

The silver lining to this cloud was an early return home to find my wife excited by a new species of butterfly in the garden.  A beautifully marked Small Copper adds to our species total making it 11 for our garden this year.