Sunday 18 December 2011

Trying for accuracy in my bird records

I am trying to get much more accurate in my bird counts, for submission to the Kent Ornithological Society (KOS) and the British Trust for Ornithology (BTO). This includes audio recording the data exactly as I count them in!




Bird count seen at or from the pits themselves: 1 Canada Goose, Branta canadensis, 3 Teal Anas crecca, 30 Gadwall, Anas strepera, 1 Wigeon, Anas penelope, 4 Pochard, Aythya ferina, 14 Tufted Duck, Aythya fuligula, 8 Mallard, Anas platyrynchos, 6 Shoveller, Anas clypeata, 1 Goosander, Mergus merganser, 2 Great Crested Grebe, Podiceps cristatus, 10 Little Grebe, Tachybaptus ruficollis, 7 Lapwing, Vanellus vanellus, 83 Black-Headed Gulls, Chroicocephalus ridibundus, 3 Common Gull, Larus canus, 5 Mute Swans, Cygnus olor, 109 Coot, Fulica atra, 9 Cormorant, Phalacrocorax carbo, 2 Jackdaws, Corvus monedula, 2 Carrion Crows, Corvus corone, 2 Magpies, Pica pica, 2 Green Woodpeckers, Picus viridis.


On the path down there were 7 Fieldfare, Turdus pilaris, 1 Blue Tit, Cyanistes caeruleus, 4 Blackbird, Turdus merula, 1 Wren, Troglodytes troglodytes, 3 Jackdaws, Corvus monedula, 3 Woodpigeon, Columba palumbus.

Saturday 17 December 2011

Nearly Christmas at the Gravel Pits

This is really quite a strange time of year as we get to a whisker away from the shortest day, the 21st December - a particularly emotional time for me as it was my father's birthday. There are both lingering elements of the season drawing to a close, and signs of the new season to come, all mixed in with the feeling of the depths of winter and the excitement of the wintering flocks of birds visiting us, seeking refuge from the icy North.

On the gravel pits the duck are thrilling, with Shoveller numbers starting to build a little bit more strongly now, Teal, and the fantastic female Goosanders (there are now THREE of them, all red-heads), all adding to the semi-resident Gadwall, Mallard and Tufted Duck. I'm still hoping for another Smew this winter, to match last year's cracker! Its difficult to get good photos of the duck at distance, so instead here is a shot of the black-headed gull roost in the second gravel pit, which is always worth a careful check!


Here are some of the group of gulls on the wooden perches to the South of the second gravel pit, and as usual this is a good place to look for Common Gulls, Larus canus. There are 3 in this picture, and these are numbers 4, 7 and 8 counting from the left in this group of 9, the others being the much commoner black-headed gulls! It may be possible to pick out the Common Gulls by their somewhat larger size, and their yellowy-green legs and bills. They are very much inshore gulls, nesting on freshwater lakes and gravel pits, and feeding on the shore and inland. They breed in colonies to which they return in successive generations (monogamous pairs persist year by year), with nearby pairs being more highly related to each other, and a surprising degree of neighbour adoption of wandering chicks. The Birdtrack records indicate numbers in this tetrad between 1 and 4 during 2010, but surprisingly there are no records shown there for 2011.


These three all look like adults, with no obvious black on the bills, although this is very easy to miss - as adults they should have thin black lines on their bills in winter, but no large black patches at the base. They could have migrated into this area for the winter, or they could be part of the resident population in the Southeast. If they have migrated here, they could be from Scandinavia or from Scotland. The total UK population is estimated to be about 50,000 birds, and all those mainly Scottish birds must go somewhere in the winter! Birds are quite subject to predation and do contain quite a diversity of helminthitic parasites, few dominant core species, like other gulls. Males take 2 - 3 years, females 3 - 4 years to start breeding.

Perhaps also they are part of a larger group that roosts here at night, and the others all move off as a flock to feed as a Common Gull group? This seems unlikely as the Common Gulls that Warren usually sees are generally mixed in with the Black-headed Gulls, and there probably aren't enough Common Gulls to make a flock of their own. It's very difficult to get to understand questions like these. Now that I have my eye in a bit, I generally see 2 or 3 birds here during the day, but I've no idea if they are usually the same birds each time, nor whether they are accompanying the Black-headed Gulls or operating independently, for at least part of the time!

Many gull species have increased their populations significantly in the twentieth century, taking advantage of new opportunities at sea and on land, following fishing boats, frequenting waste tips, following the plough, etc. Research in Germany near the Baltic indicated that the Common Gulls there preferred quieter pastures to feed on in flocks, separating their niche from the Black-headed Gulls, which were much more likely to be following the plough on disturbed arable fields. However 20% (!) of gulls following tractors in this study were still Common Gulls, although they spent more time than the BHGs foraging outside the flock, the BHGs tending to follow the tractors more closely.

The German research took seasonality into account, and counted the gulls in different fields, estimating their behaviour patterns. The arable fields in general were available as bare earth being cultivated during migration periods and the winter, but tended to have over-tall vegetation for exploitation during the summer breeding season. The Black-headed Gull numbers fluctuated by season, while the Common Gull numbers were steadier, although both species are migratory.

I wasn't very happy with the statistical approach adopted in this paper, and I think it may have obscured some of the real issues. In addition we don't know where the gulls were when they weren't on the fields, and what they were feeding on as alternate sources! They could be on waste tips, or on the intertidal flats, feeding perhaps on bivalves and polychaetes. Its also worth remembering that there is a lot of flexibility and variation between sites and years in these highly opportunistic birds!

However, according to this research, the Common Gulls spent most of their time foraging in their pastures feeding on earthworms, particularly during autumn and early winter when earthworm biomass is highest, and didn't rest as much as other species. The Black-headed Gulls fed on insects disturbed by the plough, and also spent a little time trying to catch flying insects. They feed hugely at these temporarily abundant resources, and then spend more time resting than the Common Gulls tend to. The BHGs I see by East Lock generally seem to be trying to scavenge things off the ground, either on the newly sown cereal searching from the air, or from the sheep pasture searching on the ground - mostly I don't see Common Gulls on the local farmland at all!

The intensification of arable operations should benefit BHGs, while the move from grassland to arable across Europe may negatively affect Common Gull numbers, particularly as livestock is now more supported by forage and silage, as opposed to traditional pasture grazing, which provides the undisturbed insect and earthworm-rich resources that Common Gulls seem to like.

Back to the blog, this is the causeway across the second lagoon, with great views of the Common Reed fringing the gravel pits,


This is one of the little islands in the shallow lagoon in the first pit, that Monty likes to check for nesting duck if he escapes control - I have to make sure he never does that again.


There are still fruit on the bushes to tempt the visiting winter thrushes, and this is a close-up of two rose hips - the third has already been taken, perhaps by a Fieldfare or Redwing!


The hedgerow roses often seem to have small sections where the leaves remain green and apparently functional, and I've no idea if this is simply an error by the plant, or whether it manages to get a bit more photosynthesis done by developing this little trick! Blackberries seem to retain at least some green leaves for ages.


The rose thorns are retained as well of course, those that haven't got picked up in Monty's coat as he drags through the hedgerows looking for rabbits and squirrels!


By the side of the path to the East of the first gravel pit, there are a number of Goat Willows


On the Goat Willows the buds seem to be swelling - a sign perhaps of the pussy willows to come - if so its got to be a portent of spring hoverflies to come I hope!


This particularly well coloured twig might be a Cornus I suppose?


Meanwhile the lichens continue slowly and steadily to make the most of things by colonising the bark of the oak trees, growing quietly whatever the season! These mainly crustose ones are on the vertical trunk near ground level, greatly magnified,


While these frondose ones are on the stub of a horizontal branch, broken off and rotting further along at the tip


Approaching the lock across the sheep pasture on the return journey, the alder was in its full red-headed glory with its catkins coloured up and getting ready to shed their pollen, another promise of the spring to come. As with so many alders the tree itself leans - I wonder why this is a specific characteristic in so many trees?



Just on the North side of the Lock, I found a blue tit excitedly exploring a dead or dying branch, trying to rip bits of peeling bark off, presumably looking for insects. I got a few shots despite the distance, the blocking branch and the shadows - apologies for the poor quality!.





Looking downriver, the sheep were accompanied by black-headed gulls on the meadow. I could only see a few in this view framed by the bank-side vegetation, but the framing looked rather good!


Just above the lock a big bale of straw had got dropped into the river, by accident or design, and could become a minor hazard to shipping!


On the walk back across the fields, there were some heads of the Common Hogweed, Heracleum sphondylium, and this one has just caught the light on its dried capsellas, just asking to be sown ready for next season!


In the hedgerow wind-break above the hogweed, the Fieldfares and Starlings were prominent in the bare branches and chatting to each other loudly.


Bird count seen at or from the pits themselves: 1 Canada Goose, Branta canadensis, 5 Teal Anas crecca, 57+ Gadwall, Anas strepera, 26+ Tufted Duck, Aythya fuligula, 11+ Mallard, Anas platyrynchos, 15 Shoveller, Anas clypeata, 3 Goosander, Mergus merganser, 3 Great Crested Grebe, Podiceps cristatus, 8 Little Grebe, Tachybaptus ruficollis, 140+ Lapwing, Vanellus vanellus, 3 Common Gull, Larus canus, 3 Mute Swans, Cygnus olor, 110+ Black-Headed Gulls, Chroicocephalus ridibundus, 1 Herring Gull, Larus argentatus, 110+ Coot, Fulica atra, 1 Moorhen, Gallinula chloropus, 3 Grey Heron, Ardea cinerea, 9 Cormorant, Phalacrocorax carbo, 2 Jackdaws, Corvus monedula, 1 Magpie, Pica pica. In the field at the bottom of Kelchers there were 9 Fieldfare, 7 starling, 5 blue tit, 5 Long-tailed Tit, 4 blackbird, 2 wren, 3 Goldfinch, 5 chaffinch, 7 woodpigeon

Saturday 10 December 2011

Goldeneye* at Cliffe pools

It was such a lovely day today that I couldn't resist splurging out on the fuel and heading North to Cliffe again. Monty gets a good walk there (at least that's my rationalisation!) and there is always the chance of finding a few things new, to me at least.

The weather was calm but cold, and the puddles still had a little ice at 11:30, despite the sun. There was a fly (blackbottle?) on the flowers of the Alexanders(??) along the access road where it passes the Leopard plant hire offices. I disturbed the kestrel, Subbuteo subbuteo, from the path up the middle by the side of Conoco, and admired the beautiful drake Pochards, Aythya ferina as we went up the path, disturbing a couple of redshank, Tringa totanus which were also on the West side of Conoco.

Near the end of the path on the right there was a small flock of Goldfinches, Carduelis carduelis, feeding on the thistles by the ditch, until I carelessly frightened them up into the Hawthorn, Crataegus monogyna, and then away. I managed to get a poor shot of one in the distance. There was also one with very orange, as opposed to scarlet, facial markings. I wonder if this is a feature of younger birds?


This is the same picture, with the contrast corrected in particular, which makes it look a bit more "Christmassy"!


I got some good views of the Fieldfares, Turdus pilaris, and a Redwing, Turdus iliacus, in the hawthorn bushes towards Flamingo Pool, and then I got to my usual seat - but it was occupied! I sat on the other bench, and was joined by a very pleasant couple, which got Monty far too excited - so he disgraced me by jumping up, and also by trying to chew through his lead in his impatience.

As we had got to the seat, most of the waders were spooked, quite possibly by us, which was a real shame, and they then blew off to the centre of Flamingo, well away. I felt really guilty, I'll have to try to come on weekdays and not disturb birdwatchers over the weekend. Attempting to identify most things I got about 200 Grey Plover, Pluvialis squatarola, 200 Lapwing, Vanellus vanellus, 50 Dunlin, Calidris alpina, about 25 Redshank, Tringa totanus, 10 Shelduck, Tadorna tadorna, 10+ Curlew, Numenius arquata, and 8 or so Little Egret, Egretta garzetta. There were say 35 Great Crested Grebe, Podiceps cristatus, 60 Little Grebe, Tachybatusp ruficollis, and 200+ Coot, Fulica atra, particularly on the far pool.

While talking to the pleasant couple, who were clearly experienced birders, who had migrated from Elmley while the water level was low, I spotted a drake Goldeneye, Bucephala clangula, far down at the far end of Flamingo. Despite the distance, the white sides and white cheek spot were quite easily visible. if there were any females, I'm afraid I didn't see them!

After I had got properly cold, and Monty's behaviour had got much better, we eventually got up to go. At which point, a whole load of Grey Plover, and Dunlin returned to the near beach, together with three Godwits, and I was really pleased to 98% identify one at least of them as a Bar-Tailed Godwit, Limosa lapponica, by the absence of the black band on the tail and the absence of a white band on the wing. I was pretty sure I actually saw the barring on the tail a couple of times.

I headed off down the path towards the Radar pool, and had a good look at the Black-headed Gulls, Chroicocephalus ridibundus, Herring Gulls, Larus argentatus, Lesser Black-backed Gulls, Larus fuscus, and Greater Black-backed gulls, Larus marinus. I thought I saw four or five Common Gulls, Larus canus, as well. At about this point, the gulls got spooked and I saw a fox, Vulpes vulpes, scouting along the far bank, looking for easy prey!

After walking along the path towards the Radar lookout, I picked up the drake Goldeneye again, I was a little bit nearer now, and I tried to get a photo, but it was still a long way away. It was just possible to agree the yellow eye, the very triangular head, the white cheek spot more or less correctly placed and shaped, the greenish gloss to the head, and the slight blackish tint to the area of the primaries, with the wing slightly delineated by a black line. Overall the white sides and neck were good distinguishing features from the drake Tufted Ducks, Aythya fuligunosa, together with the larger overall size, and the very active, fast swimming, often diving, behaviour.


I was particularly pleased to find that the second photo attempt caught what appeared to be the drake vocalising in a sort of "head-straight-up" position, sort of as shown in BWP Volume 1, page 662. Whether it was stirring the water behind with its feet was a bit more difficult to detect, but there was perhaps a hint of it!


The display might have been the centre point of a "mast-head" type movement, with the call, but it wasn't followed by a dive as the next photos were taken fairly quickly afterwards and show further steady swimming continuing to the right. One photo I found on the web shows the same posture in two close together males, but is interpreted as simply drinking!

There are about 200 breeding pairs of Goldeneye in the UK, mainly in the Highlands of Scotland, but most breed near Scandinavia or Russia, and move southwards and possibly westwards in Winter, some ending up here. This one could have come from Germany, Norway, Sweden, Finland, the Baltic States or Russia itself. This drake should head back with most of the others in about March or April. There were supposed to be a couple of ducks at Cliffe as well, but I didn't see them.

They breed in tree-holes, slightly unusual for diving ducks, and the story is they can easily be encouraged by adding nest-boxes to the range of possible breeding sites, thereby raising populations, used for example quite extensively in Finland and Scotland. However although the number of breeding pairs may be raised, this doesn't necessarily increase the number of young that can be bred in a particular area, according to research. This may be due to other density-dependent factors that apply, such as food supply. They feed mainly on insects and other aquatic animals, or turn to plant material, perhaps when animal material gets scarce. Another little trick the females have is brood parasitism, laying eggs in another female's nest.

I also saw a female Marsh Harrier, Circus aeruginosus, with its wings in the characteristic shallow V-shape, drifting low over the marshes behind the Black Barn. This female seems to have been seen quite regularly here.

Sunday 27 November 2011

Fungi on the way to the Gravel Pits

The last minute fungi dash to reproduce continues to impress! In the field of seedling wheat to the North of the East lock, an impressive cluster of small mushrooms has recently appeared.

By the tall hedge that crossed the footpath in the meadow to the South of the East Lock, a clump of what looked like some Pholiota have shot up - but I soon realised my mistake I forgot to get a spore print of last weeks finds, despite my iSpot promise!

Friday 25 November 2011

Golden beaches at Pensarn

After a very blowy and not very bird-rich visit to Conwy birds reserve, Monty and I went on to the various coastal viewpoints at Llandulas and Pensarn.

There were some good views of gulls at Pensarn itself, which has the most amazing beach, miles of golden sands below the stony foreshore.

This is a black-headed gull, Chroicocephalus ridibundus, close to the car on the stony higher part of the shore. It's worth expanding this photo, as it's a really smart bird close to, with a very delicate grey on its upperparts, a pure white on its underparts, black on the wings with small white spots, and a red base to the beak and orange-red legs. Notice also the white ring immediately around part of the eye. In winter the brownish head cap is lost to be replaced by these dark vertical stripes on the head, very variable from bird to bird.

The word ridibundus means laughing, in relation to its harsh call. A sociable bird very commonly found inland, migratory or resident in the UK, that takes two years to get to maturity, and may then be very long-lived - for example one bird is said to have lived for 63 years!

Wednesday 23 November 2011

Spotted at Cliffe!

As Paula left for work I walked down to the village car park to collect the car, abandoned there after an informal parish heads meeting to consider the Youth Club lease last night. It was a misty morning, dank and drear and definitely off-putting, with little chance of an enjoyable walk, let alone any bird-watching - see the Pittswood blog for an even more depressed view of the day and its bird watching potential in Hadlow. So what to do instead?

Naturally I ended up sitting in an office in the College doing gentle and mundane administrative work. I'd gone in fairly quickly after a couple of simple parish jobs, particularly as it was such a misty day and its really not so stupid to be in College if it keeps me from putting the heating on at home! I may have to find another computer to work on though, as I don't want to outstay my welcome with the horticulture team.

At about 11, I looked out of the window and noticed the sun had just appeared - bird-watching could be on the agenda again! So I went back home, checked the post, did a couple more minor parish things, and set off for Cliffe Pools with Monty.

Only when I arrived did I think to check the tide-tables, to find out I'd missed high tide by about two hours. The first birdwatching couple I met told me how good it had been on Flamingo as the high tide had driven the birds off the river and onto Flamingo and the other pools. If I'd checked the tables first thing this morning I could have had that experience myself! Curses, I said to myself, and Monty and I set off to make the best of a bad job! The weather was still fair, no complaints for the back end of November, but it was no longer sunny and had clouded over with a degree of emphasis - it clearly wasn't going to improve again!

We went fairly directly to my favourite bench overlooking the new beach at Flamingo, and Monty was very good, keeping to the path - more or less. The remaining flowers along the route were looking fairly sorry for themselves, and there were no insects around, with very few passerines. The Pochard and Tufted Duck on Conoco were making a good show however - they are such lovely animals, both of them.

There wasn't a great deal around but there were some lapwings showing well on the far side of the new beach, together with a couple of what turned out to be Golden Plover, and three Common Redshank. It was nice to spend some time thinking of the Golden/Grey differences, and I also had a good luck at the Coots, Mallard, Little Egrets, Lapwings, Golden Plover and other Redshanks over at the far side opposite the bench. In retrospect I realised that I did spend quite a bit of time looking at a rather taller, more delicate, faster moving and actively feeding Redshank. Perhaps it was even more grey than brown as well - but that's hindsight! Once I had seen its red legs I simply asked no more questions!

After a while I thought I'd move on, gathered up everything, slung the 'scope over my shoulder (I've decided its not worth putting the scope into the rucksack at Cliffe), and walked up the path with the beach petering out a short distance away on my right. Just then I noticed two Redshanks together, just on the edge of the beach.

One seemed a bit lighter in colour and more elegant - thinner and taller than the first - they just looked different - but both had orange-red legs! At last I thought of Spotted Redshank as a possible and got the telescope out. The taller one was a bit lighter and perhaps a little speckly, although not convincingly so, seemed to have a distinct white eyestripe and darker legs. This was a definite - maybe - possibility!
And then the possibility vanished somewhere under the nearside bank of the little stream. I didn't see it fly off, but this seemed a likely outcome. The other bird remained and I got the birdguide out - YES - the characters I had noted so far fitted for the absent bird. It could be worth a little patience, so I settled down to wait quietly for a bit - you never know! I started to take some pictures of what I now thought of as likely to be a Common Redshank, Tringa.

This one shows the shortish beak, red at the base, the overall brown-grey, including the quite smudgey breast, and the relative lack of an eyestripe, so that the white eye-ring shows clearly.


Here with the bird looking directly at me a whitish supercilium streak can be seen, but its not very distinct. Looking at the beak from the front and top you can see the reddish tinge to the bill where it joins the face.


The bird was quite actively feeding.



Here, taken another second later, it almost looks as though it is spitting the excess water out!


Here is a reasonable shot of the suspected Spotted Redshank, Tringa erythropus.


and here is a shot looking directly at me, in which you can see a very clear supercilium stripe on either side of the face, forming a "white eyebrows" effect.

Sunday 20 November 2011

Whetsted Gravel pits in the murk

The heavy mist made conventional bird watching impossible this morning, but there were lots of compensations as I listened as carefully as I could for birdsong.

Monty me several very pleasant dogs on the walk down to the East Lock, where we also ran into Tom and his Labrador, to Monty's great delight.

I edged out towards my vantage point at the first pit and looked for dragonfly cast skins (exuviae) on the right hand posts along the first causeway - absolutely none to be found. I may have cleared some of them a few months ago, but I wonder how long they last on such posts - do they get washed off?

As the mist was showing no sign of dispersing I put Monty on the lead and headed back to the Medway through the sheep field, trying to take care not to spook the animals. I got to the river having gradually shifted the rather large and dignified sheep off my path, and away from a couple of their favourite salt licks.
On the way back along the banks Medway the sun suddenly broke through, so I reconsidered, and changed course to return to the Gravel Pits. As I tacked diagonally South across Poor's Meadow I came to the southern margin of the field and into the shaw along the banks of the stream. Here I looked at a number of fungi, including this moderately small sized one, several of which were found on a horizontal rotting trunk, most likely an Ash, Fraxinus excelsior.

Its worth looking closely at the detail of the cap while its still attached to the trunk and before I touched it. Fairly obvious and apparent was the clearer white of the edge of the cap. It was this that first led me towards a species of Crepidotus, as this last feature was clear in the photograph of Crepidotis mollis (Schaeff.) Staude in Roger Phillips, and on several photos on the web. However there is a difficulty with this most apparently likely species, which is described as an ochre brown, with a grey-brown margin, striate (do they just mean on the margin?), gelatinous, although drying near-white. Although the cap is very white, it does perhaps look striate overall, and the fibres appear as a darker network at the left hand side, as if perhaps it was in the process of darkening further.


The same sort of pattern can be seen in the picture below. Somewhat more reassuring, there is a fuzziness dorsally to the point of attachment. This is also seen in many pictures on the internet that are said to be of C. mollis..


However there is another possible issue. Most species in the genus are characterised by having either no stem, or at most a rudimentary one. The only exception to this is C. applanatus, which appears too small and delicate to be a possibility.

In this specific example I would say there is at least a rudimentary stem, as seen here with the cap turned over. The cap has not been moved far - you can see where the stem was attached to the bare wood from which it was growing out. Personally I do now think (I have persuaded myself?) that this attachment is limited enough to be described as rudimentary, but it all depends on the definition you use! And it is beginning to have quite a Crepidotus look about it! Perhaps even an almost light pinkish colour to the gills, as in the Phillips picture, if not the description, which is cinnamon?


Well, to advance, I'm going to have to follow up! I shall put it up for the I-Spot system to tear my ideas to shreds, and I shall also try to return to the site in a couple of days to check the colour, and perhaps collect material that might produce a spore print.

Saturday 19 November 2011

Rye Harbour at dusk

After spending the bulk of the afternoon strimming the boat spaces at the sailing club, I headed off South into East Sussex to Rye Harbour to have a look at the new Nature Reserve facilities there.

I was able to take Monty out on the shingle paths and he had an absolutely great time rushing about. As the paths have been separated from the bird areas by pig netting, the dogs get their exercise while the birds are protected from grievous trespass by them!

On the other side of the River Rother the visitors were walking along the beach by the sand dunes


This side of the river the bank is almost entirely shingle, always such a beautiful mix of colours


The shingle is covered by last season's Sea Kale,


The area has always had to be guarded against invasion, while its various shorelines have extended gradually out to see. The latest time of trial was the Second World War, and the pill-boxes remain scattered about the nature reserve to the present day.


Eventually Monty and I reached the far hides, and I chose the one with the setting sun behind it, to try to get a few last minute photos. The islands in the scrape were crowded with lapwings, Vanellus vanellus. Later I saw one Redshank, Tringa and a lovely pair of Little Grebes, Podiceps, just under the windows of the hide itself.



Behind them were about a hundred plovers, which I though might have been Golden Plovers, but couldn't be sure. Further back were hundreds of Herring Gulls and Lesser Black Backed Gulls.


Spotted later on in the middle of the photo were a single Shelduck and one Oystercatcher. Can you spot them?

Here is the sunset over the Lower Greensand cliffs by Hastings. What a great hour down by the sea. I really can't understand any more why people need to travel further than the boundaries of the UK - I won't have enough time to see everything that needs to be seen in Kent, let alone the rest of England, let alone the rest of Britain!


Friday 18 November 2011

Cliffe pools at low tide, Mid-November

The weather was really rather good again today, with spells of reasonable sunshine and warm and dry whether the sun was shining or not. Common Darter, hoverflies, bee? Lots of LBJs, good numbers of pochard, tufted duck, little grebes, great crested grebes, coot, little egrets, grey herons, redshank, lapwings.
The dredger Antwerpen was off-loading at a rate of knots, and you can see the dredgings being fed from the stern.


and they are then fed up the escalator to be dumped in windrows


Along the seawall, there was a good crop of shaggy inkcaps, Coprinus comatus, of which I took one picture of a youngish head:


On the way back to the car, by one of the access gate-bars, I came across a hoverfly concentrating on a few flowers, which might be a Platycheirus, possibly Platycheirus albimanus. The combination of grey spots and a small dark body points towards the greyer marked species of Platycheirus, and the black shiny thorax with an accompanying black scutellum is a fairly diagnostic cross-check that it really is Platycheirus, characteristics shared only with Melanostoma and Chamaesyrphus. Another nice point is the wing venation, with the long light brown stigma, clearly visible on the front margin of the wing (see further down below).

This sighting, together with another unidentified Syrphid patrolling a territory on the path, was really great as I had thought that the hoverfly season was pretty nearly finished, and I haven't been able to photograph any hoverflies for weeks. I therefore tried to catch this Platycheirus hovering in front of the flower:


It was clearly grey spotted, and a female. The overall shape and pattern looks pretty good for P. albimanus overall. However a word of caution here - the unsettled nature of the taxonomy of this genus, and the overall similarity of the females in general makes this identification a matter of probabilities rather than certainties and therefore somewhat tenuous.


The sternites, overall pattern and face shape seem to fit the pictures on the web - "Wild in Denmark" is a brilliant site for this sort of comparison, with really detailed pictures. The mid and front femora more or less fit available web pictures, but not fully, nor the description in Stubbs & Falk. I would have expected to see a bit more lightness and a clearer orange in these limbs. However this may be partly due to the lateness of the season. If this is a third brood individual, then it may be expected to develop darker shades in the lower temperatures available at the larval and pupal stages.

There are a number of other issues with the identification. The abdomen of this insect is quite swollen, and apparently much contracted in relation to the length of the wings. The wings therefore seem 20% longer than the abdomen. I have seen neither of these features in any of the photographs available on the web. The legs are also proportionately long and spindly. Again I realise what poor photos these are in relation to many others available, and I do wonder whether I should make more use of the tripod in this sort of situation. Incidentally, in the next photo there also seems to be a flea beetle buried head down in the flower:


In the next picture the light brown stigmas are clearly visible, which seem to be seen in most of the web pictures I have seen. Although not in the diagnostic keys, these are useful cross-check features - its always reassuring to find such useful characteristics borne out in practical identification.