Monthly Archives: June 2012

Damsels of Fen Drayton

One of the reasons for my trip to Fen Drayton a few weeks ago was to have a look to see which of our dragonflies were out and about. I went in early June and that time of year is a little early for the true dragons to have emerged, although it’s not impossible. But despite the shortage of the true dragons, the hedgerows and lake sides were abuzz with damselflies.


Male red-eyed damselfly – Erythromma najas

Dragonflies and damselfies are the two members of the taxonomic order ‘Odanata‘ or Odanates. There are two sub-orders within the Odanata: the Anisoptera – the true dragonflies, and Zygoptera – damselflies.

Azure damselfly – Coenagrion puella – the blue form of the immature female

Damselflies in the UK are approximately 4-5cm (1.5-2 inches) long and have thin abdomens and are all smaller and more delicate than the chunkier dragonflies. Having said that, the biggest living Odanate is currently a damselfly who resides in the rainforests of Central America, it has a wingspan of 19cm (7.5 inches) and the abdomen is 10cm (4 inches) long. A real whopper!

Blue tailed damselfly – Ischnura elegans – immature femaleBlue tailed damselfly – immature male – Ischnura elegans

Male and female Odanates, and immature and mature individuals, can often be distinguished by colour. The common blue female below is conspicuously brown so the species gets its name from the electric blue colour of the male. The common blue can easily be confused with the variable damselfly which is the same blue colour, but they are distinguished by the black markings on segment 2 of the abdomen which is shaped like a goblet on the variable and a club on the common blue. Also, the antehumoral stripes (on the side of the thorax) are complete on the common blue and broken on the variable. Although, as the name suggests, the variable is indeed variable and it can make distinguishing the two species a little tricky.


Common blue damselfly female – Enallagma cyathigerum – the only common blue we saw on this trip, perched on my friends finger

The black goblet on segment 2 is visible under the front of the wings on the variable damselfly below. But confusingly, it’s living up to its name because the antehumoral stripes are unbroken.

Male damselflies have two sets of paired claspers at the end of the abdomen which it uses to clasp the female on her pronotum, which is the protrusion in the middle of the back of the head. The claspers have tiny hooks on them which match grooves in the female pronotum and in order to avoid procreational mismatches the hooks and grooves are species specific.

Variable damselfly – Coenagrion pulchellum

In the picture above a variable male has clasped his lady by the pronotum. Male damselflies have primary genitalia at the end of the abdomen on the 8th segment, but in order for fertilisation to take place he needs to transfer a ‘spermatophore’ from the primary genitalia to the secondary genitalia on the second segment at the thoracic end of the abdomen. The female then curls round in to the ‘wheel’ position to transfer the sperm to her genitalia which are underneath her 8th abdominal segment.

A pair of variable damsels in the wheel position

All the Odanates are carnivores, and the larvae which hatch from eggs layed under water are ferocious carnivores, the larger ones will even take small fish! On one occasion last year while I was photographing large red damselflies (Pyrrhosoma  nymphula), a large hawker dragonfly (I think it was a migrant hawker, Aeshna mixta) which had been buzzing around higher up for several minutes suddenly dived down and caught one of my large red damsels. In a few seconds the migrant butchered it and ate it on the wing and the inedible bits of wing and leg were discarded and rained down around me.

Scarce chaser – an immature male

A lone Anisopteran, or ‘true’ dragon was spotted on this trip and it was an immature scarce chaser, Libellula fulva. He was a lovely mustard colour and he can be differentiated from the female by the colour of the thorax which is dark grey in the female, and from the male adult who is electric blue. He undergoes quite a transformation in transitioning from immature to adult.

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The Magnificent Mute

Mute swans are beautiful birds. There are few sights as impressive as a male mute, wings cocked, protecting his youngsters. The family below were on a very small lake at RSPB Fen Drayton and just before I took the pictures below, the male had launched a pre-emptive strike against a perceived threat at the other side of the lake, around 40m away. I couldn’t see who the interloper was but the sight and the sound of the big male as he raced across the lake, wings outstretched and beating on the water, must have been extremely intimidating. It was unnerving from where I was standing!


The male on the left is back with his brood after nullifying the threat. But he’s still got his wings cocked.

The mute (Cygnus olor, Dansk: knopsvane) is one of the biggest flying birds with a wingspan greater than two metres and an average weight for the male of approximately 11kg, it is a very impressive bird indeed and a group in the air flying close by is a real jaw dropper.

In the UK mute swans belong to the monarch and no one else is allowed to take them. They are marked every year, a practice that was originally identifying them  for the monarchs table, but I think Her Maj’s palate has evolved since then and eating swans is, fortunately, no longer fashionable.

It is native to the UK and a resident breeder but when things get too cold on mainland Europe winter migrants can show up here too. They tend to remain in their home territory all year round but can also form groups in the winter and move to a winter feeding ground, presumably this behaviour is driven by the temperature, availability of food and safety in numbers.

The ‘mute‘ in ‘mute swan’ is apparently derived from the fact that the mute swan is not as noisy as other swans. I’ve strayed too close to a nest before though, and at that moment mute was probably the last adjective to spring to mind as they voiced their discontent by making a violent hissing sound to warn me off. I took the hint and retreated as swiftly as possible.

Poison Parsley

Poison parsley is another name for hemlock. Hemlock originally attained notoriety around 2500 years ago when it was used to poison the Ancient Greek philosopher, Socrates. He was executed because his teachings were highly critical of the Athenian state and he was a thorn in the side of various high ranking Athenians. And in those days that tended to limit ones life expectancy.

Hemlock – Conium maculatum

I hadn’t knowingly encountered hemlock until a couple of weekends ago when I was strolling around the RSPB reserve at Fen Drayton, where it was lining the hedgrows in some profusion. It is an imposing plant that was growing taller than me, up to around 2m, it has dark green feathery leaves and white flowers that resemble the hogweeds.


This plant was growing amongst hogweed and cow parsley, and it can appear fairly similar to both, to the uneducated eye.

A variable damselfy (Coenagrium pulchellum) warming itself in the early morning sunshine perched on a hemlock frond

The hogweeds used to provide fodder for pigs, hence the name, but giant hogweed is toxic to humans due to its sap which contains a type of chemical called a ‘furanocoumarin‘ that causes the skin to become sensitive to ultraviolet light. That can result in extremely unpleasant blistering of the skin and blindness if it gets in the eyes. Derivatives of furanocoumarins have been developed as drugs for the treatment of psoriasis.

But the hemlock toxin works in a different way. It is called ‘coniine‘ and the chemical name is 2-propylpiperidine:

I think this compound is remarkable because it is very small for a molecule which has such a specific and catastrophic effect. It exerts its effect by blocking a receptor for a neurotransmitter, acetylcholine, which resides on the membrane on the far side of nerve synapses. This results in a condition called ‘flaccid paralysis‘. Basically, the nerves which facilitate muscle contraction get blocked and stop firing. It starts in the feet and travels upwards, the muscles go floppy and that’s ultimately fatal when the effect reaches the heart and lungs. Socrates’ death was described by Plato and his last words were to his friend, Crito:

“Crito, we owe a rooster to Asclepius. Please, don’t forget to pay the debt.”

The smooth stem of the hemlock plant

The purple spots on the stem of the hemlock are diagnostic, other similar plants don’t have this, so if you see it, admire it, but don’t touch it! All parts of the plant are toxic and it doesn’t take much to have an effect.

The flower head just before the white flowers emerge

Hemlock has a number of names according the the Royal Horticultural Society: California fern, cashes, herb bennet, Nebraska fern, poison hemlock, St Benedict’s herb, snakeweed, spotted hemlock, spotted parsley and winter fern. Also according to the RHS, its range is Europe only, but it has been introduced to the United States, hence the two names which include U.S. states.

Hemlock grows in damp poorly drained soils and is fed on by various insects including caterpillars and occurs in field borders and roadside verges aswell as along the lakes and ditches where I found it at Fen Drayton.

Wee brown birdies

In the brief intervals between howling gales and torrential rain in these parts we’ve had the occasional glimpse of sunshine, and in those moments I’ve managed to grab a few pictures of some small birds; those little ones that look small and brown at a distance and can defy attempts at identification.

I’ve been a little concerned at the small numbers of certain migrants which have returned to my local patch, in particular blackcap, yellow wagtail and whitethroat.


Common whitethroat – Sylvia communis, one of the few to return to the Meadow in 2012

Last year at this time I would expect to see 5-10 whitethroat during a circumnavigation of the Meadow but this year I hadn’t seen any until I spotted this one and his mate, last week, bringing food to the nest. I also found another pair which I think are nesting in a tree on the other side of the track to this pair, but I’m yet to confirm that. And I still haven’t seen a single blackcap or yellow wagtail in 2012. Hopefully they made a successful migration back here and are just elsewhere, but I do miss ’em, they liven up my walks with the dog.


Chiffchaff – Phylloscopus collybita

A wandering warbler which has returned in numbers is the chiffchaff, and I hear them singing almost everywhere I go. This one was in a field here in Histon, and let me get close enough to take this picture, which is my favourite chiffchaff shot.

The rest of the birds in this posts are not migrants in the UK and I see them all year round. The yellowhammer is a bunting that has a very distinctive song, described in numerous field guides as ‘a-little-bit-of-bread-with-no-cheese‘. Which is a very good example of the pitfalls of trying to over-interpret birdsong! I was with my daughter when we saw (and heard) this one calling, and after telling her about the ‘little-bit-of-bread…’ thing we spent the rest of the walk thinking up alternatives. My favourite was ‘I’m-going-down-the-pub-for-a-beer‘.

Yellowhammers – Emberiza citrinella

I was particularly pleased with the second yellowhammer picture because I like the out-of-focus foliage surrounding the focussed bird. I recently upgraded my DSLR to one with more sophisticated focussing capabilities than my ageing Nikon D40x, which all my pictures up to now have been taken with. And one of the main reasons was so I could focus more quickly on small birds in bushes, such as this one, where the foliage was moving around in the breeze causing the camera to struggle to find focus. This picture was taken with my D40x and I was surprised by how well it turned out, so maybe I’d have delayed upgrading if I’d captured this image first!


Reed bunting – Emberiza schoeniclus

Reed buntings are present in the local fields and hedgerows all year round and this little chap, for he is indeed a male, was singing long and loud perched on the top of the rape flowers. A circuit around this field is an ornothological treat, on one lap I’d expect to see several reed buntings, at least one or two corn bunting, lots of skylark and occasionally linnet and goldfinch. And on Saturday (9th June) there were two bullfinch, an adult male, resplendent in his black cap and peach breast, and a male youngster, the same colours but a tad smaller and with more muted colours, perched in a tree together on the edge of the field.


Dunnock – Prunella modularis

And my favourite little brown bird is the dunnock, which are also here all year round, and in the winter are regular visitors to my garden. These two were transporting food to the youngsters in the nest in the midst of a bramble thicket. Fortunately, despite the low numbers of migrants in my locality there are still enough birds around to liven up a walk in the countryside.

Insects and molluscs

Over the last couple of weeks I’ve been out and about photographing wild flowers, and of course the raison d’etre of flowers is to produce the reproductive cells of the plant in order to ensure survival. And as plants are immobile they rely on other vectors to connect the male and female parts, that can be the wind and the rain but many flowers are exquisitely evolved to attract one or more species of insect to carry the pollen to the ovum and effect fertilisation.

So in the course of photographing the flowers some of them were hosting a pollinator or two:

Tree bumble bee – Bombus hypnorum

This tree bumle bee was sipping nectar from the flower of the white deadnettle. It’s one of the insects that is strong enough to get to the back of the flower and take the nectar. Flowers have evolved in this way such that the insects have to pass the stamen, which is where the pollen, or plant sperm, is produced. The stamen is made up of the filament and the anther, and foraging insects brush against the anther picking up pollen which they carry to the next flower where it is deposited on the female part of the plant – the ‘carpel’, and fertilisation ensues.

There are various species of bees in the UK but only around half a dozen common ones. Bees are in trouble in this country and no one seems to know why, both honey bees, which live in colonies, and solitary bumble bees are dying out at an alarming rate.

Buff tailed bumble bee – Bombus terrestris

The buff tail above was in a particularly poorly condition and had tiny mites crawling on it’s body so I imagine it didn’t do much more pollinating.

Soldier beetle – Cantharis rustica

The soldier beetles are related to the fireflies and they get their common generic name from one species which is bright red and is therefore named after the ‘redcoats‘ – English soldiers from days of yore. The larvae and the adults are carnivorous, the larvae feeding on insect eggs and caterpillars and the adults on aphids. They also feed on nectar and can therefore pollinate too.


Black slug – Arion ater

Alot of people have an aversion to slugs because of the damage they can do to fruit and vegetables, but this chap was out in the field making a meal out of a couple of dandelion seedheads. I don’t think they contribute much to pollination and they are predated by frogs and toads and also hedgehogs. Although I’ve heard that if too much of a hedgehog’s diet consists of slugs, parasitic worms living in the slugs can get into the lungs of the hedghog and kill it because its lungs fill up with fluid. Which sounds pretty unpleasant but I guess it’s not the fault of the poor old slug!


Brimstone moth – Opisthograptis luteolata

The brimstone moth is a splendid creature with a wingspan of 32-37 mm. It’s common and widespread across the UK. In the warmer climes of  the southern UK there can be three generations in a year but in the north there is only one brood per annum, and adults can be seen on the wing between April and October. The caterpillars feed on various trees and bushes including hawthorn and blackthorn.

A couple of weeks ago after days of rainfall which had moistened everything I found a 50m stretch of verge which was crawling, literally, with hundreds of yellow and brown snails.


Brown lipped snails – Ceppaea nemoralis. Just a few of the hundreds that were making the most of the damp conditions

The ‘lip‘ of the snails in their name is the front edge of the shell which can be seen in the next two pictures and is lighter brown on the yellow one and a much darker brown on the brown one:

Snails are predated by songthrushes. They pick up the snail by the fleshy part and crack the shell on a handy stone. Some years ago I was sitting at home on my own reading a book and everything was very quiet. I heard ‘tap tap tap’ on the front door, but when I went to answer it their was no one there. So I went back to my book. A few mintes later I heard the same tapping and again there was no one there, so I opened the door to have a look up the street and rather than a visitor there was a collection of broken snail shells on my front doorstep. It transpires the tapping I’d heard was a songthrush using my front doorstep as an anvil to swing the snails against and hammer open the shells!

More blooming flowers

Hedgerows, field borders and roadside verges continue to thrive in this part of the world as a result of the recent rainy weather. Nettles are in abundance at the moment, in particular the white deadnettle (Lamium album):

The white deadnettle is, as the name suggests, not a stinger, and it’s common all over the UK, Europe and Asia. It’s white or pink flowers need to be prised open in order to reach the nectar at the back of the flower so only bulky insects such as bumble bees can reach it. It flowers from March to December so it can provide a food source for these insects for most of the year.

According to the Royal Botanic Gardens at Kew, the leaves and flowers can be eaten raw when they are young and tender and the fresh leaves can also be boiled and eaten as a vegetable. The flowers can also be boiled in water and used as a traditional herbal remedy for catarrh and dropsy, which is another name for oedema, or build up of fluid under the skin. The roots can be boiled in wine, which will extract compounds that are insoluble in water into the alcohol fraction of the wine, and the resulting concoction can be used as a remedy for kidney stones. White deadnettle is also used as a herbal treatment for benign prostate hyperplasia, which is enlargement of the prostate gland, and for gastrointestinal problems. So this humble hedgerow plant has the potential to provide a plethora of therapeutic compounds.

The white deadnettle is also known as bee nettle, blind nettle, day nettle, deaf nettle, dog nettle, snake flower and white archangel.

And the other nettle which is springing up everywhere is the much maligned stinging nettle, Urtica dioica:

The flowers of the stinger are tiny and green and grow in strings which are several centimetres long. The stinging mechanism is via hairs, or ‘trichomes‘, and each one has a bulbous end that breaks off when brushed by a passer by, leaving a sharp hollow tube. The tube acts like a tiny hypodermic needle that injects a cocktail of irritant chemicals including histamine and acetycholine which potentiate an inflammatory immune response which is the cause of the stinging sensation. The sting protects the nettle from grazers but also offers protection for other species which are resistant to the sting and the stinging nettle is therefore home to various species of insect and is an important refuge for caterpillars such as that of the peacock butterfly. Before slashing them down in your garden see if you can’t find an out-of-the-way corner to let them grow and provide a home for the butterflies.

Cooking the nettle leaves removes the sting and they are rich in vitamin C so they are used to make soup, herbal tea and, latterly, pesto and in the production of a cheese called ‘yarg‘ from Cornwall.

Charlock, Sinapis arvensis

The yellow flowers of the charlock plant, also known as carlock, corn mustard, field kale, kedlock, kerlock, kinkle, wild kale and wild mustard, have sprung up along the field-side drainage ditches and hogweed, Heracleum sphondylium, is well established too:

Hogweed flowerhead

Hogweed grows all over Europe and flowers from June to August. The flowers burst out of large pods at the top of the stems and are initially pink but fade to white. The young shoots are reputed to be good to eat with a flavour similar to asparagus and the plant gets its name because it was gathered to provide feed for pigs in times past. Hogweed is also known as cow parsnip, cadweed, clogweed, eltrot, giant parsnip, madnep and meadow parsnip.

Pansy, Viola arvensis

Lurking along the edge of the nearby rape fields, almost hidden in the undergrowth, are pansies. The name of the pansy originates from the French word ‘pensee‘ – thought. It is also know as heart’s ease, ladies’ delight and stepmother’s flower.


Hedgerow cranesbill, Geranium pyrenaicum

Hedgrow cranesbill, aka mountain cranesbill, is very common at the moment. It flowers from May to August and it gets it’s name from the shape of the seedpod in some species of geranium which is long and pointed and said to resemble the beak of the crane.

Herb bennet, Geum urbanum

According to the RHS herb bennet also has a number of colourful names: blessed herb, city avens, clove root, colewort, Indian chocolate, minarta, St Benedict’s herb, star of the earth, water flower and wood avens. This plant grows in shaded spots and flowers from May to August. It has aromatic roots which have been used to flavour ale and give off a smell of cloves so it was hung by the door to ward off evil spirits. It was also used medicinally by the Romans as a substitute for quinine.

My day job is in the pharmaceutical industry so I have a professional interest in chemicals which could have medicinal applications either on their own or as cocktails of compounds which may be contained in the same plant. So when I’m researching a post like this I wonder how many species we’ve lost due to modern agricultutal practices and how much herbal knowledge and potential drug molecules have passed into history. Many have probably been lost but there are still thousands remaining to provide us with food, herbs and spices, medicines, and to add the wonderful shapes and colours to the countryside.