River Medway

The other day I took Monty for a walk from Hartlake Bridge West upriver along the North Bank of The River Medway, which looks very peaceful at this time of year:

which doesn't stop Monty having a swim in it!

The fields beside the river have just been harvested, and the wheat straw baled up for straw:

The farm, owned by the Teacher family, has quite a few corners devoted to wildlife, and the hover-flies, such as this male Sphaerophoria scripta (note the head-down position this species often adopts)

and this Eristalis species benefit accordingly:

This however really is a solitary bee, Andrena andricus! (maybe!)

while this is another Eristalis hover-fly, possibly Eristalis horticola

The butterflies also do well, such as this Brown Argus, Aricia agestis, a member of the Blues family, the Lycaenidae:

and this very tattered Meadow brown, Maniola jurtina, a member of the Browns, the Satyridae, which has obviously "lived well".

Bumblebees are also busy, such as this worker Red-tailed Bumblebee, Bombus lapidarius,

and present, as always, are the Tachinid flies:

Small Copper

I walked down to a damp area of grass down by the River Bourne to the South of the village today, and found a Small Copper, Lycaena phlaeas. The Small Copper is an excellent small butterfly, generally seen only in small numbers but still found quite regularly - and its always a pleasure to see such a colourful and delightful insect.

Its numbers are recognised as declining, but this decrease is officially thought to be not so severe as to cause any serious concern of extinction at present - although there are differing views as to the whether this analysis, based on absence/presence in relatively large quadrat squares, is sensitive enough to pick up major declines in number within local areas. The geographical coverage as measured by 1 km squares, decreased as little as 15%, but numbers may have dropped by anything up to 90%, according to a recent transect study in North Wales. The species decline that has been recognised nationally has probably been associated with wholesale agricultural improvement and habitat loss.

However breeding success seems also to be quite dependant upon weather - better in warmer years, but on the other hand perhaps negatively affected by drought, when the sorrel food plants may suffer badly. Any effects of climate change are therefore likely to be complex. One effect that has already been recognised is a more rapid lifestyle with earlier peak appearances of the adult by 2 - 10 days.

The sun was low in the sky so this particular Small Copper oriented itself at a steep angle in order to bask most effectively in its rays - the shadow of its wing can be seen on the other stem of the Bristly Oxtongue plant behind! This is very important for butterflies as they have to thermo-regulate so carefully in order to function at optimum efficiency. It may very well even have carefully chosen its particular perch for convenience to make it easier to balance as it tipped so sharply towards the vertical. In fact this butterfly may be used to being nearly completely upside down, as both sexes tend to roost head down on grass stems at night.

The butterfly is said to exist in small colonies, with relatively few adults on the wing at any one time - so its nice to think that this one sighting might represent a colony in this area by the Bourne! This one should be an example of the second generation. We would normally expect three generations a year, peaking in late May, August and late September, with occasionally four generations in an exceptional year.

The primary larval foodplants are all Docks, Rumex species, Common Sorrel (R. acetosa), Sheep's Sorrel (R. acetosella) and sometimes Broad-leaved Dock (R. obtusifolius). The adults tend to be found in the variety of open areas where these plants are found, and will nectar there on Fleabane and a large variety of other members of the daisy family, heathers, buttercups and clovers. There is plenty of Fleabane, and other Asteraceae, in flower in this particular area at the moment.

The Small Copper tends to be a very active butterfly, fast-flying and often remaining mobile while nectaring. Males defend small territories while females characteristically fly low while hunting for egg-laying sites. The eggs are laid singly on the underside or upperside of dock leaves, white at first then grey, and last for two to three weeks. The larvae hatch and feed in grooves eaten out of the underside of the leaves (windowing). The overwintering generation hibernates as one of the first three instars. Pupation is low down on, or by, the food plants.

Its quite a variable butterfly with a very large number of colour forms. The Irish subspecies hibernica is differentiated from the British suspecies eleus by a more greyish colour on the underwings.

Grasshoppers and Bush-Crickets (Orthoptera)

Today I went on the Kent Wildlife Trust's Study Day on Grasshoppers and Bush Crickets run by the excellent Dan and Kate. After the classroom session in the morning we visited both Burham Down and Burham Marshes and found 9 out of the 10 possible species we were looking for. These were the Meadow Grasshopper, the Field Grasshopper and the Lesser Marsh Grasshopper on the Grasshopper side and the Dark Bush-Cricket, Roesel's Bush-Cricket, the Speckled Bush-Cricket, the Oak Bush-Cricket, the Short-Winged Cone-Head and the Long-Winged Cone-Head on the Bush-Cricket side. In addition Dan also found the Common Earwig and the Short-winged Earwig, which are now also included in this insect group, the Orthoptera.

Over the whole day we learnt a huge amount about identifying these common and fascinating insects from their appearance. We also discovered that Grasshoppers and Bush-Crickets can be differentiated to species by the songs the males produce, which can generally be heard more easily by using a "bat" detector. One of the really good species was the Lesser Marsh Grasshopper, which feeds on the quite rare plant the Marsh Mallow, amonst other plants. The Marsh Mallow is only found in a relatively few places in the UK. Burham Marshes and the nearby Holborough Marshes on the other side of The Medway are one of the two sites in Kent, and therefore important.

Amongst many other differences, grasshoppers have short antennae and are herbivorous, while bush crickets have long antennae and eat anything to hand, including each other on occasion!

I didn't get any photographs today, as we were chasing new species so much, but here are some previous attempts from other days, partly to illustrate the difference between the species!

Firstly here are some pictures of a Roesel's Bush Cricket that I saw at Broadwater Forest back in July. We saw this species again today, on the down, and really handsome it is too, with the immediately obvious light U shape picked out on the side of the thorax!

Picture to come.

Secondly, this is the Dark Bush Cricket, Pholidoptera griseoaptera, seen on Wednesday at the Elgar Wildlife Pond in the College grounds. It often gets darker than this individual, but I am still reasonably confident that this is the correct identification. This one is a female, as seen from the huge curved ovipositor projecting out at the back, in the picture directly below, and one of the lower pictures. This is used to insert the eggs into the soil or a plant stem, or in this case into fissures in wood, as is this species' habit.

This is the very common Meadow Grasshopper, Chorthippus parallelus, this one found on a grassy path by farmland on the Southern outskirts of "Hadlow Castle". Its not very easy getting photos inside, and I'm afraid it soon hopped off, leaving me with not very many images to work with! Still, the parallel sides to the pronotum (the shield over the thorax) and the black knees of the huge jumping hind legs are I think fairly clear.

This is a male, with reasonable lengthy wings, and the tip of the abdomen is turned up and just starting to turn orange.

Bechstein's Bat survey

I was lucky enough to be included in the Kent Bat Group team doing a Bechstein's Bat survey towards Edenbridge on Friday night. As the sun went down we carried all the gear down the track into the wood, unpacked the two harp traps and set them up in the specific positions that John and Shirley picked out amongst the trees in the middle of the wood. Its a very complex set-up that needs quite a lot of care to prevent damage.

We had some problems with the lure on our trap which plays "social calls" to encourage the bats to come down to the trap to investigate. However we managed to first get a long-eared bat,

and then we got a pipistrelle, which was quite vocal in the hand,

The other team got three more long-eared bats, which adds further weight to the suggestion that these are far commoner than just bat detector use might indicate, as their calls are so quiet that they are very difficult to detect.

We had packed up by midnight and we were all home by 1 a.m. A pretty good night overall!

Dene Park

No posting with photographs specifically from today I'm afraid, as I was on voluntary extra safety boat duty for the sailing club at Bewl. However as well as visiting the wildlife pond behind the Elgar block yesterday I also took Monty up to Dene Park woods for a walk, so here are some more photographs from yesterday.

The Meadow Browns, Maniola jurtina, had been forced off the grassy meadow by the car park (where they were laying eggs on the Yorkshire Fog grass, Holcus lanata) after all the grass was cut last week by the maintenance crew, and had sought refuge in the nearby sections of the woodland paths and rides, at least able to get nectar from the hardheads, Knautia arvensis. This one was in quite good condition and displayed its more colourful fore-wings well,

While this one was holding its fore-wings hidden behind its hind-wings and was very well camouflaged against the dead twigs and leaves on the ground, which it was testing with its tongue:

Since the paths have been cut back by an Allen cutter, there has been a little burst of flowering over the past few days at the junction in the rides from the common field speedwell, Veronica persica:

Hover-flies were present in good numbers and diversity along the path, including the currently ubiquitous tiny narrow-bodied Sphaerophoria scripta, which was resting up on some leaves low down by the side of the path, making a rather blurry photograph. This is a male:

A little further along the path, the hogweed flowers were attracting quite a range of hover-flies as usual, including this tiny Meliscaeva cinctella, very similar to Spaerophora scripta but with a clearly different pattern on the abdomen upperside, although the photo is again a bit blurry,

Sphaerophora and Meliscaeva are both of a similar size and rather similar yellow and black pattern to some of the smaller true wasp species - the more Sphaerophora and Meliscaeva look like a wasp, the less likely they are to be attacked by birds, which are "once stung, twice shy" - Batesian mimicry. There are many more wasp species than people generally think, such as this beautiful one, much smaller than the familiar yellowjacket, also taking nectar from the ever-popular hogweed, Heracleum sphondylium.

This is a much more difficult bover-fly to identify, very small and dark

and this is an Eristalis species, probably Eristalis pertinax, the one I think I generally see in Dene Park. This particular photo shows the face and the sides of the thorax particularly well. The face has a very thin central black line running down it, and it is also possible to see the plumose hairs on the side of the arista, the thin extension of the short antenna. The thorax is hairy, and overall the fly resembles a honey-bee, hopefully enough to deceive and put off most bird species that don't specialise in tackling such noxious insects as bees, with their foul-tasting venom. Specialist feeders such as flycatchers are less easily fooled by this mimicry.

I also saw one individual of the stunning solitary bee-mimic (more Batesian mimicry), the hover-fly Criorhina floccosa which looks as though its an Elizabethan dandy all decorated with feathery ruffs.

This is a much larger hover-fly, Volucella inanis, one of the biggest UK species, which is quite rare nationally, but rather common around London and in the surrounding counties. I've seen it in the hedgerows between Hadlow and East Peckham, and now also here:

This is a Small White butterfly, Pieris rapae, a stronger flier than the Green Veined White, and generally more commonly found outside woods, but on this occasion nectaring from the knapweed flowers Knautia arvensis commonly found along the sides of the rides:

And this is Rhingia rostrata, a small "snouted" hoverfly species that is quite rare on a national scale (notable in the red data book). This is the second time, at least, I've seen it at Dene Park, although I've not seen it's much commoner close relative Rhingia campestris at all yet!

The most common bumblebee seen here at the moment is the Common Carder Bee Bombus pascuorum which is often seen on the knapweed flowers, which it can tackle with its longer face and tongue. This may well be a male "drone", as it doesn't seem to have pollen baskets on its rear legs :

This beautiful hover-fly below was new to me, and took me ages to get on the right track for its identification. Its pretty definitely in the genus Melangyna (my first Melangyna!) because of its black rear legs (except for the inside of the tibiae and tarsi which are lighter in this insect at least) coupled with the colour pattern on the abdomen upperside, the grey dusting on the sides of the thorax and the face pattern when viewed from the front. At the moment the species most likely to be in the frame is Melangyna labiatarum, which is supposed to be a Southern species separated from the Northern Melangyna compositarum, but these might actually just be variants of the same species.

The pictures on Google and the Hoverfly Recording Scheme confirm that this ID is likely, with a brown rather than shiny black thorax, light or golden and not black hairs on the thorax, pairs of generally oblong lemon yellow spots on the upperside of the abdomen, clearly all nearer the front of the tergites (the upper abdominal plates) with the front pair of spots extending to the sides with a narrower bridge and joining to the similarly coloured lemon yellow underside of the abdomen. As in most hover-fly genera, this is easily seen to be a female when viewed from the front, with its eyes well separated.

To finish off, this a fairly good picture of another Sphaerophora scripta, in this case a female, showing the partial dark face stripe, and a different colour pattern on the abdomen upperside:

Elgar wildlife pond

While waiting to finish off some work at College late on in the morning I walked over to the very small wildlife pond behind the Elgar building. This tiny pond was built only a few metres from a bend in the River Bourne in a quiet and sheltered spot behind one of the College teaching blocks. Its often good for animal activity in the pond and a nice mixture of flowers and insects around it, especially if you stand quietly and wait for the insects to appear around you.

The first species seen was a quite common hover-fly, but that I've not seen before, Helophilus pendulus. I'm not too surprised to find it next to a shallow pond as the larva is a "rat-tailed" maggot that lives in water and feeds off decaying vegetation. I have seen another, more local, species, Helophilus hybridus, in the woodland in Dene Park where there are some very suitable looking stagnant ponds! All members of the genus have these characteristic yellow-striped "waistcoats" on their thoraxes.

Next along was the adult stage of a very common hover-fly, Eristalis pertinax, which is another species with a rat-tailed maggot larva, that develops in rich, often polluted, waters. The adults are far more dainty feeders in comparison, visiting flowers such as umbellifers for pollen and nectar.

And this I rather think is the somewhat less common Eristalis horticola which has got a dumpier shape and slightly brighter patches on the top of its abdomen than E. pertenax.

and here is the rather frightening Tachinid fly, Tachina vera, covered in the vicious-looking spines characteristic of the group, nowhere near as attractive as the colourful hover-flies or Syrphidae.

All the time bees of different sorts were buzzing in and out of the flowers, burying themselves up to the neck and more, in the hooded labiate flowers - this individual is very faded due to age, so is a bit difficult to identify:

and small sawflies searched insatiably for suitable plant hosts to lay their eggs in (I think this is Arge ochropus, one of the "rose" sawflies known to horticulturist (there seems to be a glut of rather similar sawflies around at the moment, for example on the strawberry fields post published just previously:

Eventually a large brown field cricket revealed its presence, creeping out from the undergrowth.

and the tiny hover-fly Syritta pipiens, with its massively inflated hind femurs, attached itself to one ray of a small hawk-bit flowerhead

while Green Veined White Butterflies, Pieris napi, flew past and, very occasionally, settled long enough to have their photographs taken while taking nectar from the mint flowers:

A Beautiful Demoiselle, Calopteryx virgo, fluttered across the pond and settled behind some vegetation, so I was unable to get a decent photograph,

and finally, as I turned to leave, a male common darter dragonfly Sympetrum striolatum appeared, hovering over the pond, and finally settling to rest on a head of mint flowers:

The strawberry fields

Only a relatively steady walk with Monty today through the "strawberry fields" owned by Hugh Lowe Farms on the Lower Greensand Ridge. The farm is rather well off for hedgerows and shaws, useful to shield the poly-tunnels they use to grow the strawberries in, from spoiling the long-distance views.

The farm is partly on the South-facing slope of the ridge, between West Peckham half way up the hill and Hadlow down on the Medway Floodplain. I parked at West Peckham, where they were playing cricket on the green in front of the pub, and walked downhill along the footpath with high hedges either side until I broke out into the open arable land just above the earth-bank reservoir put in to irrigate the strawberries, and Hazel Wood just alongside it.

I had a quick look at the reservoir hoping for some migrant waders, but only accidentally put up a young cormorant, which circled rapidly to gain height and then flew off. Along the tracks alongside the reservoir there were hundreds of Bristly Ox-tongue plants, Picris echioides, with remarkably variable degrees of green and red in their stems, ranging from one extreme to another in different plants just next to each other. Their bristly leaves are pretty characteristic, only Bristly Ox-tongue has these unusual prickly spines arising from raised white welts on the upper leaf surface, as well as many further spines on the margin of the leaf!

Of all the many plants I saw during this walk (between 4 and 6 p.m., in the late afternoon) only one flowerhead was open, presumably because of the time of day to which the individual plants are almost universally tied in their rythms. This was the still open flowerhead, with the Y-shaped styles of many of the florets still open, seeking pollination,

while all the other flowerheads were closed up ready for the cool and moisture of the night. At this stage the spiny inner and outer bracts are both held upright around the flower in protective "vases".

Once the individual florets in a head are fertilised each floret develops into a dry single-seeded fruit called an achene, each with its own built-in parachute attached above it for dispersal. The fruiting heads of the parachutes, each with dozens of individual achenes are similar to the well-known dandelion "clock", as shown in the photo of a Bristly Ox-tongue fruiting head below. There are very green stems on this particular plant in comparison to many others which are much redder. The other thing to notice is how the spiny inner and outer bracts have now both turned down, and the platform of the "receptacle" that all the achenes are sitting on has now been pushed up and expanded into a very flat dome, presumably all to allow the easier dispersal of the parachutes:

The individual achenes are much more clearly seen when half of them are removed, for example by the breeze, as in this particular fruiting head here

Specifically for Bristly Oxtongue, amongst half a dozen of its very similar-looking relatives, each achene has an extended neck about its own length again, connecting it to its parachute, which consist of many individually feathered plumes (the feathering is visible if you magnify the image further) to aid the "floating" effect that we all marvel at as they drift past us in the slightest breeze. I think that they are incredibly beautiful in their utilitarian design, when seen in this close-up detail!

A receptacle emptied of achenes has the abandoned look of a rusting launch-pad from which the rockets have been fired, and for which there is no more funding for future missions!

Note the very vibrant red in this particular plant's stems, so different from the green-stemmed plants photographed above!

The only butterflies I saw were Meadow Browns, with Gatekeepers and Small and Lrge Whites all in reasonable numbers. There were hardly any hoverflies about, and no dragonflies to be seen at all. There was however a small and predominantly orange solitary wasp seen on hogweed flower umbels on many of the field margins, which I think is new to me (STOP PRESS - this is a sawfly, and most likely to be the turnip sawfly, Agre rosae as only its shoulders are black, not the whole top of the thorax as in the rose sawfly Agre Ochropus - see next post !!!):

and there were plenty of blackberries, some of which I sampled!