Leysdown-on-Sea

A blowy day with quite a few others reporting birds like Pomarine Skuas flying past off the headlands of Kent.

Not quite so much in the brief time I was at Leysdown, but quite a few gannets way out to sea. On the shore some nice Herring Gulls.

This I think is a First Winter bird, as it has a dark eye, dark beak pretty much all the way to the tip, and rather pointy white tips to the primaries. However it might be a relatively immature Second Winter bird. It is possible that this bird is still growing some new outer primaries.

Stigmella aceris in the front garden

A nice mine to find, |Stigmella aceris on the Norway Maple of course. The only Stigmella known to occur on Norsway and Field Maple, there is a different species, Stigmella speciosa on Sycamore. The mine is filled with brown frass by this stage, my specimen does rather follow the vein a little more closely than in most photos on the web!

I could just about convince myself that I had found an egg at the start of the mine. The mine was paler at the far (expanded) end, perhaps where was less (or perhaps no) frass to fill the mine.

The larvae has been gone for many weeks of course - although I couldn't find an exit hole until I looked very carefully at the top surface of the leaf, where the final section of epidermis above the mine did appear to be missing.!

Oare Marshes thinking of Golden Plover again

The Golden Plover at Oare 

Eurasian Golden Plover, Pluvialis apricaria (Gravenhorst, 1820), (Desvignes, 1856). An interesting bird that seems to have declined in its UK breeding population steadily over the last few decades, perhaps due to changes including reductions in keepering on upland moorland, consequent increased carrion crow predation, reduction in moorland burning, possibly increased raptor numbers, or many other factors.

The much larger overwintering Golden Plover population from northern Europe, Russia and Iceland does also seem to have shifted its wintering distribution in the UK away from pastures in the West towards (particularly) arable land on the eastern side of the country since the 1980s. The Kent birds might seem to prefer grassland still but I well remember seeing birds on ploughed fields in Yorkshire on one journey up to see or pick up Simon.

In the early part of the winter in Kent, large numbers can be seen in the Swale and specifically at Oare Marshes. Today there must have been getting on for a thousand birds here at Oare today.  It is one of the twenty two sites listed in the non-breeding SPA for this species, each site being a multispecies SPA.

The plumages of the birds are quite variable in detail. This might be a juvenile or first winter bird on the left - underside more speckled further down the flanks and belly, and ONLY IN MY PERSONAL VIEW, a little warmer in the face and the supercilium thereby a bit less contrasty.

I checked for slender (long-legged?) birds with somewhat clearer supercilia and long wings projecting beyond their tails - but no possible American Golden Plovers as far as I could see!

The overall ecology of the bird is very interesting:

Moorland Breeding

In the small and declining UK population the birds nest on moorland, although during the incubation period the adults really like to feed on neighbouring farmland pastures on worms and cranefly larvae, etc, while their partners are incubating the eggs. During the day the males incubate and the females feed, and during the night the females incubate and the males feed. Tipulids are a key feature of both the later adult and the chick diet. Pearce-Higgins and Yalden showed in one of their South Pennines studies (2003) that the particular arable, improved and pasture fields chosen by the off-duty birds for foraging in were those with appropriate pasture sward heights, appropriate moisture levels and good numbers of earthworms and particularly cranefly (Tipulid) larvae. Over time, sheep stocking density has increased in UK uplands, which might be helpful, but is also associated with agricultural intensification such as drainage, which would probably reduce Tipulid numbers.

According to Whittingham et al., working on moorland in Northern England in 2001, chicks on the moorland tend to use mosaics of dwarf shrubs such as willow, crowberry and bilberry, and more open areas of cotton-grass and bare peat. Again Tipulids and Beetle larvae do tend to be very important in the diet. Rotational strip-burning or careful manipulation of grazing management systems could be used to help maintain these mosaics.

Later in 2011 Pearce-Higgins did some very interesting theoretical modelling on the extent of the impact of expected climate change on this population on the southern edge of its range, and suggested that the impacts would greatly reduce Tipulid numbers, and chick survivability, and proposed equivalent increased management activity to help maintain the population, either environmental management to increase Tipulid food sources by 80%, or by reducing nest and egg predation by 35%.

There are birds in Sweden that also breed in the uplands, like the UK breeding population, although the habitat there is referred to as Fennoscandian arctic tundra. Machin et al in 2017 showed that the chicks in this habitat in Sweden feed on a more diverse diet of beetle larvae, cranefly larvae and St Marks Fly (Bibionids) larvae, and breeding success appears to be at least in part linked to Bibionid population fluctuations from year to year. The Bibionids are found more in willow scrub, and the chicks may move into this habitat as they grow in part according to prey availability, but also in part in order to gain increased protection from predator attack.

Over-wintering

After the young have fledged, the adults and young migrate to lowland farmland and coastal habitats for the autumn and the winter. According to Gillings et al., in 2007, in recent decades winter populations of both Golden Plover and Lapwings appear to have switched from using pastures in the west of the country to using arable land for much of the winter - October - February (harrowed fields for winter cereal initially, then sugar beet and then other crops). Large open fields which had been manured were particularly favoured, and it is perhaps to be hoped that both manuring and sugar beet growing will continue into the future for these large numbers of birds over-wintering in the UK. However the reasons underlying the move and whether the pastures have become less attractive, or the arable more attractive, or both or neither remains a bit of a mystery. Could climate change have impacted on the relative attractiveness of these two types of habitats? In France research reported in 2007 indicated that cereal fields were the preferred wintering habitat in that country.

As for field size, Leitão and Peris working in Portugal in the late 90s concluded that Golden Plovers avoided fields less than 10 Ha, and preferred fields larger than 20 Ha, and preferred pastures in this particular environment.

Birds migrating from further North and East in Europe and Russia use arable fields in southern Sweden as autumn staging posts, where Lindstrm et al. showed in 2010 that numbers tend to be quite high and they are able to both moult and then also (critically) put on weight after their moult for the next stages of their journey, perhaps to the UK. The adults and young follow more or less the same pattern although the young do follow the adults after a little delay. The length of stay on these fields is about three months, August to November, indicating the importance of this habitat to this population of migrating birds.

Research reported by Piersma et al in 2003 into birds over-wintering in the Netherlands showed some fascinating patterns. The birds put on weight in the autumn (September - November) and their weights peak in late November and December as they (presumably) put on fat to sustain themselves in bad times. They then lose weight again - I imagine as they use up their reserves, perhaps with somewhat poorer food availability. Then in the spring they start to put on weight again, perhaps as food becomes more available again, in preparation for their spring migration and the breeding season to come.

However between the 80s and 90s, the December peak mass decreased as the weight gain stopped earlier, although the rate of increase during the shorter period of weight gain remained the same. As weather conditions remained similar, this was interpreted as a response to increased raptor numbers, such as Peregrines and Goshawks - possibly leading to slimmer fitter birds more adapted to raptor evasion. However this seems to me to be a rather over-optimistic view of the ability of these birds to plan ahead, and to control their weight!

Machin et al reported in 2015 on individual winter movements of birds from a breeding population in Swedish Lapland, showing that some started their winters in NW Europe in areas such as northern France, and shifted south to Spain or Africa in cold spells, giving a degree of flexibility to their over-wintering, while others sometimes didn't move further and stuck out the cold spells where they were. Cold weather movements were noticeably long and fast, real escape movements.

Hothfield Churchyard lichens

Ros Bennett took us on a fascinating tour of Hothfield Common and then Hothfield churchyard to search for lichens:

Aspicilia

Aspicilia calcarea. This is the lichen described as being like big white splashes of paint on rocks such as hard limestone (as in the British Lichens website) - or in this case walls and tombstones. In overall appearance it is a very white rounded splash. In detail however it is described as being a slightly bluish-white, with one or more unevenly outlined apothecia buried into areolae, with quite a distinct margin to the thallus. In this picture there are some areas of brownish stains, where there are fewer apothecia present.

The picture below of this thallus from Hothfield is much less cropped:

The Aspicilia genus is generally characterised by its largely sunken "apothecia" although they do project normally from time to time. The genus also often has a slightly cracked to distinctly areolate appearance of a generally light coloured thallus on rocks, usually (but not invariably) calcareous. The growth form is often variable, sometimes dramatically so.

There is a quite similar species of Aspicilia found fairly regularly on concrete in towns, Aspicilia contorta subsp. hoffmanniana.

Caloplaca

This is probably one of the Caloplaca species, and should I think be Caloplaca aurantia, with flattened lobes on the placodioid margins. That feature distinguishes it from another common churchyard lichen, Caloplaca flavescens, which has more convex lobes.

This species has darker apothecia, orange to dark brown as they go over. Between the older thallus and the fresh creamy orange lobes, there may appear an apparently lighter zone.

Here is a more cropped photo of the marginal lobes, emphasising the flattened lobes. The Caloplaca is fighting for space with the white crustose species.

Caloplaca teicholyta is a grey species, that looks rather "dirty" with some patches darker than others.

Here is a close-up of the "coral-like" lobules.

Haematomma

This should be Haematomma ochroleucum in both its forms, the whitish (var. porphyrium, lacking usnic acid) and the yellow-grey, var. ochroleucum, with usnic acid). The surface is quite powdery, leprose or farinose.

Lady Amherst's Drive

A quick visit to Lady Amherst's Drive in Goathurst Common this afternoon, parking in the small car park by the cross roads.

In a very brief moment or two I had a look at a few of the young Beech trees in among the sweet Chestnuts, and found Stigmella tityrella and Stigmella hemargyrella. There were also a couple of Phyllonorycter maestingella and one really old but possible Phyllonorycter messaniella.

I thought I might have found a couple of Parornix fagivora, but in the end I couldn't be sure - possibly just a couple of S. hemargyrella mines on the edge of the leaf.

A few "bump" galls as well.

The site is definitely worth another look though!

High Tide at Oare

The light wasn't very good, but the company was very pleasant!

This particular Ruff, Philomachus now within Calidris pugnax, was very neatly coloured, and with somewhat yellowish-green legs:

This bird shows a very scaly back, one of the characteristic features of the species. It is quite a warm peachy colour (still?). I wonder if it has been breeding up on the High Siberian Arctic.

A bit misty from the Trosley viewpoint.

A bit difficult to see far over the Weald from the viewpoint from the footpath (Harrison Drive). The mist and other factors.

Monty has been so good to me over the last ten years, and he has still got a few last lessons to teach me - it is up to me to learn them well.

I have been very lucky, but its not really the day for leaf-miners today.

I did spot a remarkable witch's broom on this Beech by the entrance road.

Ryarsh Wood

A slow amble with Monty today, and a few

Trosley Country Park

I found one very likely Phyllonorycter tenerella (Joannis, 1915) Hornbeam Midget mine today - In this case much less than half the width of the available lamina between two side veins, and starting at the midrib running well over half the distance towards the margin. The mine was also inhabited, although having torn it open I may well have sealed the fate of this caterpillar to die before it achieved its further pupal and adult potential!

The picture below is of the mine from the upper-side of the leaf - well eaten and browned, narrow and tightly folded, and long. Interestingly there was some further feeding damage and even webbing at the ends of the mine - perhaps caused by something else, possibly a Tortricoid?

Phyllonorycter tenerella is a species of southeastern England, as well as of Europe. There are reasonable numbers of regular records from Kent, high in 2008 and 2009, as for other leaf-miners I think. David Solly seems to have been very good indeed at finding them over the years!

As far as other leaf miners go, there were also some (not many) Phyllonorycter esperella mines on the upperside of the leaves and quite a few Stigmella probably microtheriella mines running largely up and down the veins. I also saw a few galls caused by what I have called "vein mites" Aceria tenella (Nalepa).

The Hornbeams at Trosley are quite variable, some young, some older, some coppiced, some maidens. This one is a moderately young Hornbeam, apparently a maiden, never been coppiced. It does look possibly a bit root-bound!

This one is another potential maiden, but quite a lot older! This suggests that there hasn't been much coppicing going on in this are of this particular woodland for quite a long time. This might match the history of the wood as a private estate, rather than a worked woodland.

There is an older picture of the grounds on the internet, of unknown date, but indicating their amenity nature at that time.

I saw two trees that were covered in fruit, and wondered why the distribution of fruit was so unequal across the woodland. I collected a couple of dozen fruit to see if they could be germinated.

Hazel Wood

Walked down from West Peckham in somewhat murky weather, and into Hazel Wood which had regrown and thickened up considerably since its last coppicing!

The Hornbeam and Oak in the first part of the wood are quite traditional. Further down there is more Sweet Chestnut and Aspen. Birch and Hazel are scattered throughout.

Some of the older Hornbeam and Sweet Chestnuts were in trouble:

On the Hornbeam there wasn't a lot of caterpillar damage, and there were relatively few leafminers and galls. There seemed to be reasonable numbers of probable Stigmella microtheriella and Phyllonorycter esperella, with a very small number of probable Phyllonorycter tenerella.

It was interesting to see that what might have been taken for old summer mines of Phyllonorycter messeniella that were indicated by shortly oblong brown patches had in fact been caused by mines of probable Stigmella microtheriella "cutting off" oblongs of tissue by running up one vein, cutting across from that vein to another, and then down that other, and then cutting back to the first - I need to watch out for this rather unexpected pattern, seen at least three times today!

I was surprised not to see any mite galls in the leaf vein axils, and overall I would say that it was a relatively disappointing walk from both the leafminer and gall point of view. The terrible light and miserable murky conditions did NOT help.

Monty struggled a bit with his back legs.

More Hornbeam at Dene Park

Interesting to walk along the old western boundary of Princes Wood beyond Fox Wood, by the old Hornbeam bank to what is mapped as Claygate Wood, although there were not that many leaf-miners or galls in this area. I had expected more, because of the apparently long history of Hornbeams in this spot.

Again Phyllonorycter esperella, the Dark Hornbeam Midget, was actively present on the upper-surface of leaves, and I tried to find some caterpillars or pupae to rear on to adulthood. However I found neither for certain.

Here are two (one fairly active looking) mines of Phyllonorycter esperella on the upperside of one Hornbeam (Carpinus betulus) leaf. There often seems to be a brownish spot in the centre of an active mine, which could perhaps be frass. However I think the frass is deposited around the perimeter of the mine. The colour tends to be noticeably silver. The mine is said to be flat, and indeed rarely seems to have significant creases. It normally lies over at least one side vein. The outline of the mine is almost rounded, perhaps oval, of very variable size, but apparently not often controlled by the vein pattern.

This is an older mine from the summer, demonstrating the way the leaf has been "pulled up" into a trough by the mine as it tightens. As the mine decays, the leaf surface often seems to recover its integrity and level off. However in this case the "damage" seems more permanent and critical.

Here is another mine, perhaps younger, but broken open and with the leaf beneath looking very good. Perhaps this caterpillar is still at the sap sucking stage, or maybe it is a very shallow feeder. The leaf is also showing the midrib wrinkling associated with Aceria tenella mites.

The leaf on the right is showing an underside leafmine that is short enough to look like an active Phyllonorycter messaniella, perhaps rather unusual to see this so late in the season - unfortunately I didn't collect it. The shoot in the middle has got some good healthy winter buds on it, already developed.

The Hornbeams are starting to turn now, with this interesting pattern of individual leaves being very different in their colour changes, sometimes giving this beautiful pattern.

More leafmines on Hornbeam at Dene Park

Another good walk with Monty, steadily looking for leaf-miners. Today I did reasonably well for Phyllonorycter tenerella, with perhaps half a dozen mines found (none seen before earlier this year - have they just appeared, or have I been missing them??) and even more obvious on the upper-surface were the new blotches of this autumn's generation of Phyllonorycter esperella.

Oare again

Still lots of twitchers, most of them looking at the Wilson's Phalarope and the Long-billed Dowitcher.

Wilson's Phalarope at Oare Marshes

Rather a lovely bird!

Alder leafminers and mite galls at Haysden Country Park

Had a very short (but quite productive) hour at Haysden, where we went along the path towards the Flood Storage Barrier, looking primarily for Alder Leafminers and Galls. There were one or two fair sized Alders by the Shallows (as in the photo below) and then a good line of them along the Straight Mile. There were also a few young plants by the weir at the end of the Straight Mile. All were the Common Alder, Alnus glutinosa.

There were some Agromyza alnivora, and some galls on the leaf surface. The first I saw were small lumps scattered over the upper leaf surface, and slightly "mushroom-shaped" so might have been Eriophyes (Phytoptus) laevis. Even the galls close to the midrib were not confined to the vein axils.

The second type, further along the Straight Mile, were bumps along the midrib specifically in the vein angles, opening below, so were probably Aceria nalepai (Eriophyes inangulis). The usual leafhopper damage is also visible again.

With the Pouch Gall Acalitus brevitarsus, also seen at this site as well as at Leybourne, this brings me up to all the three mite types mentioned in Redfern and Shirley now hopefully identified.

The rusty-brown hairs on the underside of the galls were nice and clear, if a bit dark here.

Also widespread was this rust fungus, mainly on the underside of the leaves, possibly Melampsoridium alni, betulinum or hiratsukanum. M. alni is apparently only found in Asia, while M. betulinum has been noted in the UK (Scotland?) in the past, for example causing a bit of an outbreak in the 1990s. The last of these however is perhaps most likely, a newly introduced rust, since about 2000, potentially causing early defoliation and thus some economic impact on Alder species, particularly Alnus incana.

Going back to the Leafminers, here is what might be the top surface indications of Phyllonorycter kleemannella = klemannella, the Dark Alder Midget, nominally at least small, oval and often away from the midrib. The larvae are supposedly found in May/June and July/August, quite a lot earlier than this particular record, but the Dutch suggest there may be \a third generation increasingly recently.

This "cutout" might have been caused by an earlier leafminer scar that has dropped completely out, and if so, the long and thin shape suggests that it might have been Phyllonorycter froelichiella, the Broad-barred Midget. There are other possibilities though, and even kleemannella = klemannella can be long and thin and look like froelichiella....

As well as probable Aceria nalepai galls, this leaf might just be showing a leaf-mine of Caloptilia falconipenella, as it is right on the margin of the leaf and shows a bit of turning over of the margin. This moth is however nationally scarce B, so the mine might be of something else.

Alder Leafminers at Leybourne.

A successful visit this afternoon, with a reasonable good variety of leaf-mines found, concentrating entirely on Alder. Plenty of birds around, Blue Tits, Coots, Moorhen, Cormorants, Great Crested Grebes.

I concentrated mainly on Common Alder, Alnus glutinosa, but I was also able to spend some time on the Italian Alder, Alnus cordifolia and the Grey Alder, Alnus incana .

One of the really enjoyable finds was one mine of Heterarthus vagans on one of the large Italian Alders at the southern edge of The Ocean. The pupation disc was really nice and obvious, and gives us the possible opportunity of rearing the pupa through to adulthood. I have found this species once before at Leybourne, earlier this month  - although that time I had it down as on Common Alder, when found on the 19th September. It is known to occur on both species.

Another excitement was my first sighting (as far as I know) of Phyllonorycter stettinensis, the only Phyllonorycter to be found on the upperside of Alder leaves. This was seen on Common Alder. The appearance of this Phyllonorycter was noticeably different to the normal matt colours of those on the underside of the leaves - the P. stettinensis mine is a glossy light green, then turning brown. The mine is often over a vein, and may be quite strongly creased.

Another species I could recognise was Phyllonorycter rajella, with its strong crease on the surface of the mine, close to the midrib of the leaf.

More difficult to be sure of were the relatively uncreased oval mines on the underside of the leaves close to or away from the midrib, which I would imagine were mainly Phyllonorycter kleemaniella - but difficult to separate clearly from Phyllonorycter froelichiella, which is also oval and uncreased, but longer, normally over 25 mm long.

Here is a fairly reasonable picture of what I think is a reasonably early (and active) stage of the sawfly mine Fenusa dohrnii in an Italian Alder leaf. It was towards the upper side of the leaf, with frass tending to gather in the centre of the mine (as in one of the Blaadmineerders photos for example), and "spilt out" over a major vein towards the margin of the leaf, as noted for this species. There was only one mine in this particular leaf, but most other factors seemed to fit, and it is a relatively common mine.

The larva takes about three weeks to complete its mine, and then pupates outside, eventually becoming a tiny (c. 4 mm.), mainly black, sawfly. At the moment this mine is relatively translucent and has not yet developed the opaque mid-brown colour, often in the end highly crinkled, of the mine to be seen in its later stages.

Slightly less exciting than some of the other leafminers were reasonable numbers of the usually common Agromyza alnivora, the only fly miner found on Alder species in the UK to my knowledge.

Lullingstone and leafminers with a start to a personal key

Anne and I added ourselves onto The Ash Project's basic tree identification course run by Mike Phillips run at Lullingstone this morning. I came across some Alder mines, at least one of which that fitted Phyllonorycter rajella fairly well from its shape, position and single strong crease, a mine that I don't think I have found elsewhere yet, so very pleasing to see.

Lullingstone is a fairly dry site, and the Alders I was looking at were in the (probably) deliberately planted shaws running uphill from the visitor centre. These seem popular feeding spots with the migrating swallows and martins by the way.

The mines were on the underside of the leaf, close to the midrib and with a single strong crease running longitudinally along the mine. There was one fresh, and several slightly older mines, one of which exactly fitted rajella. The distinguishing feature of the strong crease was new to me, despite the apparent commonness of the species, the Common Alder Midget. The mine is sometimes described as triangular but it may extend further across the leaf making it more rectangular (picture in Eakring Birds). There were several other mines, and although none were entirely diagnostic, any of the three underside species could have been there.

Personal Key to Common Alder Phyllonorycter species 

All these are between the veins on the underside of the leaf,

Near the midribnormally, maybe triangular, single strong crease, Mines in June-July, and again September - October, common: rajella (Lullingstone, Mote Park). Larvae green, if found.

Short, a few weak creases perhaps, June-July, September - October, common: klemannella (Leybourne, Bourne, Mote Park). This is by far the commonest in my limited experience. The larva, if ever found, should be generally quite pale and also rather obviously yellow in the middle sections.

Long, near full half-width of leaf, uncreased, September - October, common: froelichiella. The larva should be grey, if found.


This one, however, is on the upperside of the leaf

Maybe between, maybe over, a vein, with a strong crease, July, and again in October, "common"; stettinensis. UK Moths has: "it forms a small oval mine on the upper leaf surface, with a crease down the centre. Unlike other species that form an upperside mine, the surface is not papery, but quite glossy and heavily creased. The mine begins green and then turns orange or brown when more mature." Wikipedia has that "the frass is deposited in a corner of the mine".  


Grey Alder

Generally similar to Common Alder, except that the long mine of froelichiella is replaced by a different long mine, that of a nationally notable species, strigulatella.


Italian Alder

A restricted list, consisting of just the two fairly shortish species: strongly creased rajella and the only weakly creased klemannella.



One of the Stigmella species was found as well on the Common Alder.

There were also old galls which were probably formed by Acalitus brevitarsus, pouches extending above the leafblade, with now rusty coloured hairs beneath.