Blog Archives: WildWivenhoe

#WildWivenhoe Botany & Bug Walks: October – Cockaynes Wood

It has been said that ‘Words are easy, like the wind’, but some words we learned on our walk today were not particularly easy, in fact decidedly complex!  Pangaea and Gondwanaland two for starters, not to mention Samara and Parthenogenesis….

The first two cropped up in relation to two beech trees, the European Beech and Southern Beech which stand at the edge of the track down to Cockaynes Wood, the destination of our Botany and Bug walks this month.

These two distantly related species, albeit in different families, share a common ancestor which occurred many millions of years ago on Pangaea, a supercontinent that included all the landmasses of the Earth. That subsequently broke up into Gondwanaland (present day South America, Africa, Arabia, Madagascar, India, Australia, and Antarctica) and Laurasia (everywhere else).  When the separation occurred, the common ancestor went with each landmass, but different climates and natural selection pressures drove the evolution of two now-separate families. It was recognition of such relationships which gave some of the most convincing evidence for the new theory of continental drift, as recently as the early part of the 20th Century.

Our main focus this month was the trees and fungi of the wood, and some of the creatures therein.  Whilst fungi were not particularly plentiful, we found some of interest including a ‘troop’ (yes, it is the collective noun) of Puffballs forming a fairy ring, a Deceiver, Birch Bracket, plus our old favourite the Fly Agaric.  This familiar red and white toadstool grows associated with Birch, and although there are many of these trees in the wood ( so plentiful in fact that they need to be managed to keep them under control, particularly in the open heathland areas), we only found one small patch to admire.  Fly Agaric is renowned for its hallucinogenic properties, and being plentiful in Lapland has been associated with flying reindeer, and the whole red-and-white Santa Claus phenomenon.

A Witch’s broom, often mistaken for a bird’s nest, is often also caused by a fungus, in this case the fungus Taphrina betulina on Silver Birch, one of several microfungi we encountered. Others included the powdery mildew Microsphaera alphitoides on Oak leaves and the rust fungus Phragmidium violaceum, red splodges on the upperside of Bramble leaves, and erupting volcanoes of black spores below.

A few invertebrates were also on show.  A suite of our favourite bugs – Squash, Green Shield and Forest;  a splendid Devil’s Coach Horse beetle which adopted its fiercest pose; Pine Ladybirds; plus a pristine Painted Lady basking in the weak morning sun.  It is hard to believe that these fragile-looking creatures are migratory and able to fly thousands of miles.  Those on the afternoon walk missed the adult, but an eagle-eyed member of the group spotted the caterpillar, itself an amazing beastie.

Spiders and harvestmen (arachnids, not insects, due to not having the requisite six legs) were out in force ready to catch careless flies for lunch.  Some, like the familiar Garden Spider, produce sticky webs to effect this whilst others rely on stealth.  It was also a privilege to see the very active Hornet’s nest in a hollow tree.  These huge, beautiful creatures are much maligned, but if left alone are not aggressive or harmful, and they do much good in gardens and woodlands, helping to control the legions of aphids and other ‘pests’.

And so to another of our words of the day, ‘parthenogenesis’, meaning asexual reproduction.  The wonderfully named Virgin Bagworm, living on assorted fence posts, indeed lives a pure lifestyle.  These weeny wingless moths produce tiny bags which they decorate with lichen, and in which they (all females, no boys allowed, in fact they don’t exist) live for their whole life.  They can produce babies all by themselves with no help from anyone.  Hope it doesn’t catch on!

As for the trees in the wood itself, Sweet Chestnuts were plentiful, in places their leaves sculpted by the excisions of leaf-cutter bees, along with Holly, English Oak and Silver Birch. Hornbeams were at the fruiting stage, producing masses of dangling papery bunches, bunches of winged seeds or ‘samaras’, the last in our lexicon of odd words.

We finished the day with a flourish, seeing a Common Lizard basking in the glorious afternoon sunshine, an amazing aggregation of Scatopsid flies (aka Black Scavenger Flies), plus a veritable collection of Odonata  (dragonflies to you and me) hanging around, catching the last rays of the day: a Migrant Hawker, a few Common Darters, and  several Willow Emerald damselflies, a recent colonist of the British Isles, assumed to be one of the (rather few) upsides of Man-induced climate change, better thought of as climate breakdown, catastrophe even.

As always, many thanks to you all, old friends and new, that joined us .

The Beth Chatto Gardens throughout the Seasons: September

Summer returning with a flourish, sun streaming from a cobalt sky, but the signs are there… autumn is upon us, the leaves are turning. And also falling, seemingly on the early side, perhaps one result of a droughty August.

Before the fiery flames of high autumn sweep through Nature’s realm, delicate pastel shades  are more to the fore…

…with colour-bursts and blasts to remind us of the summer now departed.

A lower sun extracts hues, textures and patterns from the garden that may otherwise be missed.

Still plenty of nectar and pollen sources around…

…and insects to take advantage.

Others basking wherever they can, to warm up enough for the the final act, their legacy, producing the next generation. It was especially good to see several shrubs festooned with the metallic green matchsticks that are Willow Emerald damselflies, only recently established in Britain, but now a reliable feature of early autumn here.

 

In the wider countryside, Ivy is the final main course of the season, its flowers vats of nectar and pollen, enveloped in a heady, sensual, musky poll of scent, and the persistent hum of a myriad of visiting wings. Even with blowsy blossoms as a distraction, the allure of Ivy which has decided to make the garden its home still pulls them in.

Down at the ponds, Thalia, that (not very ) beautiful assassin (see last month’s blog), is still exerting its fatal attraction.

Spiders too are taking their toll on the insects, but at least they – unlike Thalia – eat their victims.

And it was particularly exciting to be shown a Wasp Spider which has taken up residence in the Dry Garden, feasting on the local grasshoppers. While not uncommon in rough grassland right by the estuary, this is the first time we have seen it in the Beth Chatto Garden, a space for plants and all that they encourage.

 

#WildWivenhoe Botany & Bug walks: September – Ferry Marsh, after The Flood

 

Ferry Marsh is part of the Colne Local Nature Reserve, owned and managed by Colchester Borough Council, and this was our destination for September. In days of yore, part of this area was a grazing marsh, but more recently, since the housing development on West Quay, it has been set aside for nature conservation purposes. Rainwater falling on the roofs of the new properties is directed onto the marsh;  this, together with springs and tributary streams, keeps it damp and the channels full of water for their famous occupants, the Water Voles. The idea is that the sluice into the River Colne allows excess water to drain out at low tide, but as locals know this system has been prone to go awry and for the past couple of years the whole marsh has become more or less permanently flooded. How did this affect the wildlife? Well this is the question we were interested in.

Although the weather forecast had been good, hey ho, the wind and the rain plagued us in the morning session, with a resultant meagre selection of insects. The sunshine in the afternoon warmed up some additional species, including both Ruddy and Common Darter dragonflies, two colour-forms of the tiny Slender Groundhopper and a picture-winged fly Ceroxys urticae.

But the morning session was not without its entomological interest, and we were treated to four butterfly species, including a splendid fresh-out-of-the-pupa Red Admiral, as well as Green-veined White, Small White and Painted Lady, plus some wonderfully-named Long-winged Coneheads and a stunning Roesel’s Bush-cricket.

Having been totally inundated for some considerable time, most of what is currently supported by the marsh has only been present since the water-level subsided. This is obviously true for most of the plants, but also for creatures such as the Green Shield-bug, which we saw in various stages of development. An adult earlier this year would have flown in and laid eggs on a suitable food plant. The subsequent baby bugs ( known as instars), unable to fly, gradually munched their way through the relevant herbage, shedding their skins up to five times, until they reach adulthood and only then acquired wings, and, as Chris would say, ‘ naughty bits’.

Talking of sayings, you may know the phrase ‘Sedges have edges and Rushes are round ‘. This was demonstrated to be true whilst examining the plant life. Confusion is only just round the corner, though, as the Club-rush is actually a sedge, whilst what we think of as a Bulrush, is not a rush at all, nor a Reed, but a Reedmace. The joy of our inaccurate English names!

Whilst the beautiful Common Reed takes pride of place, both visually and aurally, at present, we also discussed some of the many other plants which have colonised, including  Gipsywort and several species of yellow ‘composites’ like Prickly Ox-tongue, Prickly Lettuce, Fleabane and Sow-thistle (some of which were covered in this glorious purple blister-gall, caused by a gall-midge Cystiphora sonchi).

A surprising find was a single plant of the rare Jersey Cudweed, in a very different habitat to the cracks in the paving slabs on West Quay which it colonised five or so years ago. As we saw at the end of the walks, it flourishes there and seems not to be met with a barrage of glyphosate – do go and admire it if you haven’t already.

Unfortunately, no one spotted a Water Vole, though we understand they are doing well, and were able to survive the flooding due to the foresight of Darren Tansley and those who constructed the water channels and built a high bank in between them, which provided a refuge. The Spotting Award this month must go to one of our afternoon group, who incredibly saw a Common Lizard basking in the sun, not on the ground as you might expect, but nestled a metre or so up in a hedge!

As always, thanks to you all who joined us.

Our new toy – a compact portable moth trap

Living in a top floor flat has many advantages – the light, the views, the health benefits of 53 stairs to climb – but it isn’t really compatible with regular moth-trapping. Lack of space means our large Robinson trap is now relegated to the loft space, emerging only on special occasions, and those are restricted to times when we have access to mains electricity or a generator.

A chance meeting in Cambridge Botanic Garden alerted us to new style, truly portable LED traps now available from our friends at Anglian Lepidopterist Supplies. Run off a rechargeable small battery pack, LEDs have been sourced which emit strongly in the UV light spectrum, the frequencies which many moths respond strongly to. This helped overcome our scepticism about LED traps, and we decided to invest.

The trap has now had four outings, so time for a review. Our expectations were managed at the outset with the suggestion it was likely to be most effective in very dark conditions, so we had no high hopes when we ran it in a friend’s urban garden with skyglow, only 10m away, but shaded from, his 125W MV trap light. It was good to see the light still on first thing – the battery had performed to expectations – but compared with the adjacent MV, fewer free-range moths outside the trap. However once inside, it was a very pleasant surprise to find a goodly proportion of the species from the big trap, including a Privet Hawk, three Elephant Hawks, Scarce Footmen, Least Carpets and Brown-tails,

Apart from the greater number, the only things in the big trap which turned us appropriately green with envy was a Green Silver-lines and an L-album Wainscot, and we had several species not in the big one, including Bright-line Brown-eye, Iron Prominent and Latticed Heath, together with the distinctive nose-down micro Pediasia aridella and a Sexton-beetle.

Second outing was close to the Wivenhoe Barrier, overlooking salt-marshes, a generally dark zone but again with distracting intrusion from security lights. Almost instantly the LEDs attracted hundreds of Water Veneers, a short-lived whitish micromoth which emerges in a coordinated way to maximise the chance of meeting and breeding.  Ruby Tiger, Yellow Shell, Diamond-back, Cloaked Minor and Dingy Footman also popped in, along with the mayfly Cloeon dipterum, several caddisflies, and from an entirely different habitat, a Nut Weevil.

Two nights’ later in the same locality, it was a rather different picture. A little cooler, a little breezier, a more lingering twilight, and no emergence of Water Veneers. But again a few moths came in the hour or so of dark we were there, mostly LBJ micros (many being Bryotropha species) with only one different macro, a Rosy Rustic.

Finally, a truly dark location, Wivenhoe Old Cemetery, an old Victorian graveyard which has grown up into woodland, where trapping sadly terminated a bit early because of rain. The attraction was instant, the diversity reasonable, including several Orange Swifts and Straw Underwings, together with micros such as Nephopterix angustella (still considered to be an Essex Red Data species, despite recent increases) and Mint Moth, and the usual variety of hangers’-on, including caddis-flies, Nut Weevils and damsel-bug nymphs.

In a nutshell, this LED trap will never supersede an MV trap for numbers (of individuals or species), but not everyone has the time to process five hundred or more moths in the morning. But with the phasing out of mercury, MV bulbs are on the way out. And the portability (and flatpack storage) of the LED trap means that is likely to be the future of mothing for us.

 

The Beth Chatto Gardens throughout the seasons: August

High summer, those languid, lazy days of sunshine and leisure…if you are human. But for the rest of the world, a time of frantic activity, flowering, seeding, feeding and breeding. Many of the flowers are fading, evidence their job is done, though some like Echinacea and Asters reserve their finest show for the later months, just as the throngs of insects need it the most.

And what a range of insects and other invertebrates, from butterflies and bugs to micromoths and flies, with as always spiders taking their share:

But  wear and tear on leaves is also a positive sign, indicative of the feeding activity of those mobile garden adornments which will bring movement, excitement and joy to next year’s borders.

Down by the water’s edge, summer was only just bursting, with swathes of colour, and flashes of magic from dragonflies and damselflies.

But all was not as serene as it seemed. Large clumps of flowering Thalia dealbata in the ponds were clearly a magnet for insects of all sorts, hunting nectar and pollen…

…but on closer examination, each flowerhead was riddled with corpses – hoverflies, lacewings, bees, wasps and blow flies – a mortuary for those valuable garden assistants, pollinators and predators alike, all stuck headfirst into the mouths of their nemesis.

The scale of the carnage, was quite simply shocking. Some, still alive, like this Honeybee we managed to release, but most were dead. Lost to the world.

Reference to the internet shows this is a recognised phenomenon. The plant has no reason to kill its visitors – it doesn’t digest them like a truly carnivorous species: it seems that the flowers have an elastic style, used in explosive pollination which can and does trap insects In its native central American range it is normally pollinated by large and powerful Carpenter Bees, capable of extricating themselves from the flower’s fatal embrace. Anything smaller, mere collateral damage, cannon fodder in the battle for life.

But at times of an Extinction Crisis, that is one pressure our array of pollinators, necessary not just for the plants but for our species’ continued existence, can do without, dozens of pollinator lives extinguished unnecessarily for each flowerhead. The Beth Chatto online sales catalogue does at least draw attention to this antisocial behaviour of Thalia, but none of the other websites I have visited, nor the RHS make any reference to it. Time for a campaign, maybe a ban, but at least removal of the flowering spikes before they open. It’s not as if they are especially attractive, the main value of the plant being its architectural emergent foliage.

On a happier note to end with, one of the great advantages of being naturalists is that people bring us specimens. And so it was today when a proffered pot revealed its treasure, a Tanner Beetle Prionus coriarius that the Education Team had just found, something that neither of us had seen before.  A large, blackish longhorn, it is considered to be rather rare in Britain, found at scattered localities in the south of the country, and is usually associated with ancient woodland or extensive natural landscapes like the New Forest. Its larvae, like those of Stag Beetles, develop over several years inside rotting wood, and the National Biodiversity Network map shows one previous record close to Elmstead Market, but very few others in and to the east of Colchester.

 

 

#WildWivenhoe Botany & Bug walks: August – The Shipyard and Barrier Marsh at dusk

We decided to try something new this month – the long warm nights seemed too good an opportunity to miss –  so we spent two very enjoyable evenings with some of you local nature-fans enjoying the beauty that is Wivenhoe, with some wildlife thrown in!

The jetty is a wonderful spot for admiring the river, the salt marshes and the big Essex sky.  Looking heavenwards on Saturday we were privileged to witness a ‘Sun dog’.  This phenomenon only occurs when the time of day, year, and weather conditions are just so.  Sun dogs come about when the “22 degree halo round the sun intersects with the parhelic circle centred on a point directly the observer” (phew!) and are manifested as two fleeting bright spots like rainbows, either side of the sun.  And like rainbows we all see our ‘own’ version of them, directly in line with our visual gaze.

Monday evening was different,  a more traditional cloud- and water-scape sunset, but those who were waiting on the jetty a few moments before we started were lucky enough to hear and see a Kingfisher, quite unusual for this time of year, although a frequent visitor to the dock in the winter months.

We  discussed the history of the river, and the various benefits/ disadvantages of the barrier.  Of course, it keeps Wivenhoe and much of Colchester safe from flooding  (a distinct benefit!), but at the cost of altering river flows. Along with the cessation of dredging now the upstream ports have closed, this means silt is building up.  This in itself is not all bad news of course – the accretion of mud is allowing salt marsh plants to become established.

Some, like Sea Aster, are useful nectar sources; others such as Marsh Samphire are edible for us humans (though possibly being so near the sewage works at the Hythe makes that a  less-than-appetising prospect!). Sea-purslane is noteworthy, being its own desalination plant – it takes in salt water and excretes crystals of salt from its leaves.

Common Cord-grass has an interesting provenance, being a hybrid of two types of cord-grass, one native and one from America, but unlike most hybrids which are generally infertile has now become able to reproduce by seed and as a consequence is spreading.  At present it is not a problem here in Wivenhoe, but its aggressive growth, at the expense of native plants, is proving troublesome on some salt marshes.

The two-leaved form of the Four-leaved Allseed is a small and unprepossessing plant, but very rare and grows for unknown reasons along patches of Walter Radcliffe Road.  This is despite the best efforts of Trinity Estates to eradicate it  (along with anything else that has the audacity to try to grow along our roadsides) with highly toxic chemicals.  This plant used to be known only in the far south-west of England, but recently been spotted along the Thames Embankment and has now arrived at Wivenhoe.  On boots, boats or car tyres?  We shall never know.

The seawall beyond the Sailing Club is well stocked with plants particularly suited for the salty conditions – including Strawberry Clover and Dittander – which bring some welcome colour and of course food for insects.

On Barrier Marsh itself are myriads of anthills, some very ancient, a good indicator of unploughed and infrequently inundated marshland.  Though we well remember December 2013 when due to the ‘perfect storm’ conditions of low pressure and spring tide, the sea wall was overtopped – here’s a flashback, and perhaps a vision of the future:

A walk across the marsh did not unfortunately bring forth any Glow-worms on either evening but the presence of three species of bat was picked up thanks to our clever detector.  This ‘Batscanner’ automatically switches to whichever frequency is being emitted by any passing bat – each species uses a unique frequency to ‘echolocate’, so if you can find out one you can work out the other.  On Saturday two species of Pipistrelle were picked up, and on Monday the larger, more uncommon Serotine.

Talking of new toys, these evenings  were opportunities  for us to try out our new battery-operated portable LED moth trap.  Not having being road-tested before, we were delighted how far that little candle threw his beams, attracting several species of those most mysterious of nocturnal creatures.  On Saturday a huge number, hundreds in fact,  of tiny white Water Veneer moths, appeared.  These have a very short adult life-span, sometimes only hours, so we were glad to provide an opportunity for lots of them to ‘get together’ to do what moths do, and hopefully when we turned the light off at 10.30 they all had the opportunity to fly off and lay their resultant eggs (the females anyway!).

Other moths that paid us a visit included Ruby Tiger, Dingy Footman (dubbed by one of our group as the ‘Pumpkin seed moth’), Cloaked Minor, Yellow Shell, Maple Prominent and Garden Carpet. Don’t they have brilliant English names?  Of course they all have their Latinised scientific names too, but generally moth-ers only refer to the tiny micromoths, which do not have catchy common names, by these.

But there are exceptions: Water Veneers have already been mentioned, while the Diamond-back Moth, of which a couple dropped in, deserve a common name by virtue of their distinctive markings and habit of arriving on our shores after migrating from the Continent on wings only 8mm long.

Other creatures popped in to say hello too, attracted by the light – Harlequin Ladybird, caddisflies, a  mayfly and a cute Nut Weevil.   Once everyone had had the chance to have a look, all were released and allowed to carry on their nocturnal business unharmed and undetained.

It was surprising how the difference in conditions (more breeze, less cloud cover resulting in a lighter evening) made the mothing less productive on Monday.  Interestingly there was not one Water Veneer, supporting the theory that these, and many other creatures, all emerge at precisely the same time.  After all, it is no good hoping to mate if there is no one else around to mate with!  A few tiny micromoths fluttered in and out, but the main catch of that evening was a Rosy Rustic.

All photos in this report are our own, but other than the moths and sunsets, most were not actually taken on the nights in question, due to poor light conditions.  We hope that everyone who came along enjoyed this venture into the unknown!