Leybourne again by round pond

I was again trying to age the Canada Geese by the watersports area, but they still all look adult to me! There is an interesting Canadian website http://www.peregrineprints.com/zzzz_Article_WCgeese.htm
with some very good pictures on it, also differentiating between the Feral, Todd's and Cackling Geese. The Sibley Guide is also excellent, http://www.sibleyguides.com/2009/10/ageing-canada-geese/.

The juvenile plumage should be quite distinct, with shorter and narrower feathers, tapering to a rounded tip. The differences should be most marked on the scapulars, tail and underparts. However other sources (in particular the book Wild Geese by Ogilvie) seem less sure that these are reliable features!

However BWP suggests that there is a plumage called "first winter" which is intermediate between the juvenile and adult plumages, and this seems quite sensible to me. BWP also states that there should be a post-juvenile partial moult of the head, body and tail in "early autumn".  

Trosley Country Park

Trosley is a superb example of complex woodland structure, with trees of a multitude of species, ages and form. There are upright monoliths, fallen monsters (some with daughter trees springing up along their fallen lengths), tall lanky uprights, coppiced stools, seedlings, etc.

Below the Visitor Centre there are two Horse-chestnut monoliths, literally on their last legs. There are excellent fungal brackets, apparently of at least two different species, and also great opportunities for wood-attacking wasps such as Ectemnius.

The female above (sting fairly clearly seen at the rear in some of the other photos, and no knobbly antennae as in most males) might be Ectemnius cavifrons, one of the commoner and larger species. There appeared to be no yellow on the abdominal stergae, a supporting feature separating this species from E. sexcinctus in Yeo and Corbet. 

A brief return to Beacon Wood

I went back to Beacon Wood for a brief walk with Monty, driving through a sharp rainstorm just before I arrived. The weather improved greatly during the visit.

As I arrived at the clearing with the picnic table, I saw a fat wasp on the leaves low down on the treeline, which turned out to be Chlorotoxum cautum, a wasp-mimic hoverfly.

Bourneside Meadows

The landscape down towards Bourneside Meadow does not seem to have benefited from the small amounts of rain so far, and the whole area feels dry and almost devastated. The crop of forage beans have been sprayed with dessicant, and stand with blackened stems that rattle loudly against each other whenever Monty gets into them.

Alongside the crop margins there are lots of Prickly Sowthistle, Sonchus asper, mostly with white woolly seed (really cypsela) heads, and going over rapidly. Some of the old plants are heavily covered with a powdery mildew, and overall therefore even the weeds are struggling. Intriguingly there are young plants from earlier seeds already forming rosettes ready for the winter and flowering next year.

It was nice to see the first of a series of male Common Blue butterflies. Polyommatus icarus, as I turned off the track towards the meadow, and I think I saw a total of about 9 males altogether, with perhaps 3 females as well. This one is a male:

For the whole time I stayed within the meadow I didn't see any Brown Argus butterflies, Aricia agestes. However as I left, I did find four, all together in the very long grass alongside the river bank, trying to roost and settle on the grass stems and leaves being blown about by the wind. This communal roosting is characteristic behaviour of both this species and the Common Blue. The Brown Argus does seem to be give a much more silvery impression overall in flight, as well as perhaps being slightly smaller and narrower.

There were regular overflights from various white butterflies whilst I was at the meadow, and I did get close to one of them, which turned out to be a male Green-veined White, Pieris napi, nectaring on a Mint flowerhead. I know it was a male because it only had one dark spot on the upperside of the forewing, whilst females have two, and tend to have much darker forewings overall. It was nice to check the wing patterning, and the almost blue-greenish white hairs on and around the body. The hairs themselves might be white, but look blue-greenish just against the body.

The hairs extend around the abdomen, although this is not always so easily seen.

This butterfly on the other hand, seen later in the meadow nearer the river, was much more likely to be a male Small White, Pieris rapae, because of the lack of black triangular markings at the ends of the veins on the outer margin, although the overall upper wing pattern is very similar.

It was great to see the substantial clumps of Mint. The rounded terminal flowerheads and projecting stamens suggest that it is probably Water Mint, Mentha aquatica, supporting the generally wet nature of the ground around the large pond. The leaves were very hairy, not obviously petiolate on first glance (but they must have been, and this was confirmed on close examination), rounded with generally forwardly bluntly projecting teeth. The flowers were lilac, and a few mm in length with triangular calyx teeth as described in the books. Standard number of 4 stamens in the genus, with a central style and stigma, together with equal calyx teeth, (corolla and) calyx hairy on the outside in this species.

To the West of Hartlake Bridge

Quite a few White butterflies around today, and if the picture below has been correctly identified, they were all Small Whites, Pieris rapae.

There were also several Comma butterflies (Polygonia c-album) along the path - I was particularly glad to see these as it seemed to me that the numbers of Commas are a bit down, in contrast to the recovery of the Small Tortoiseshells. I really cannot tell if these are the "lighter underneath and brighter on top" Hutchinsonii form that should produce a second 2014 generation in early autumn this year, as the sunlight and shade so affect our perceptions.

A little further on I found a tiny insect on a Mayweed flower that I thought might be a solitary bee. On looking at the photos on the computer screen it turned out to be Microdynerus exilis a solitary "potter" wasp that uses old beetle holes in decaying wood and whose larvae are fed on weevil larvae. It is nationally scarce, Southern in distribution, and only added to the British list in 1937.

Here is a link to a Flickr page showing the sort of hole this potter wasp might possibly be using.

https://www.flickr.com/photos/pennymetal/14499206175/in/pool-wild_bees

On the Bramble flowers there was a well posed Episyrphus balteatus, a very common hoverfly indeed this year.

As usual there were a lot of Banded Demoiselles, Calopteryx splendens, around the river area.

and this is a close-up of the female on a Bristly Oxtongue, Helminthotheca echioides, inflorescence:

The Bourne Valley to Malt Cottage

Walking down through the Green Lane Shaw, there were a fair number of hoverflies patrolling their territories. Most I thought were the Marmalade Hoverfly, Episyrphus balteatus, but this was a Myathropa florea that was buzzing loudly and had taken control of some leaves in a patch of sunlight.

This is Leucozona lucorum, a rather tatty specimen from the currently declining first generation.

Many of the herbaceous plants were suffering from the dryness of the soil and the heat, and were already flagging this early in the season. The Hawthorn fruit continue to swell into haws - it seems that the season is progressing very quickly indeed! There is one on the left that appears not to have been fertilised. The epidermis of the fruit is slightly hairy, at least at this stage.

Here you can see even more clearly the swelling inferior ovary, with its sparse hairs and the remains of the calyx and the other floral parts above it, apart from the petals which dropped off weeks ago.

Further along the walk the Norway Maple keys were also developing gorgeously:

The elms were starting to show the Elm Leaf Gall,

In the Green Lane, I found a moderate stand of Hedge Woundwort, Stachys sylvatica, at the Bourneside end of the shaw.

As I  moved out into the arable fields along the river, the Honeybees were working the flowering Forage Beans across the fields.

The Vetch I saw most today was in the Common Vetch aggregate, Vicia sativa. This plant looks like ssp. segetalis as in the BSBI plant crib, as it seemed more or less isophyllous, the tendrils are branched, with a clear slightly bi-coloured flower (standard somewhat paler than wings). There is more taxonomic information here http://archive.bsbi.org.uk/Wats12p1.pdf. This includes the suggestion that the calyx teeth should be shorter than the calyx tube, as here. It would be nice to check the pods and the seeds later, perhaps I should mark some typical plants so that I can go back to them in a few weeks.

This a close-up of the flower.





This ant looks yellowish, perhaps because the light is behind it. It had come down from the flower above.

This shows the dark patch generally seen on the stipules, and the hairs covering the plant.

This is the leaflets close up - its fascinating how the genes can apparently code for such a variety of leaf shapes! I wonder how long it would take a computer programmer to code for growth to produce the same results? Are the slightly spiky tips of the leaflets defensive or for some other purpose? The spikes are a bit longer in the currently cultivated form Vicia sativa ssp sativa.

Most of the Buttercups I saw today were Creeping Buttercup, Ranunculus repens. However there were patches of Meadow Buttercup, Ranunculus acris around, including at the edge of the crop in the field to the North of the bridge over the Bourne leading towards Barnes Place.

I think the beetles are flea beetles:

Many of this plant's flowers are already setting achenes, very similar to those of the Creeping Buttercup. Interesting pattern of light in these!

and this one shows the same pattern as well - air spaces around the seeds compared to double thickness wall edges perhaps? Or is it just that the seeds inside the fruit are themselves white? Anyway it's very pretty.

Here is Hedge Mustard, Sisymbium officinale, this one's buds just opening.

It was  nice to see some birds flitting around the hedgerows. The nicest I thought was this male Yellowhammer on the Eastern side of the reservoir b y Malt Cottage.

Even more heavily cropped, this Linnet:

Bod Petrual - Cheilosia and Buttercups

A really great Forestry Commission site in deepest Denbighshire, even if I didn't hear the hoped for wood warblers and Redstarts on my late morning visit today! This is one of the fine parts of the huge Glocaenog Forest.

This Cheilosia on Creeping Buttercup, Ranunculus repens, really ought to be the albitarsis/ranunculi group. The first thing to note is that this insect is a male with a blue-black thorax and slightly darkened wings, and generally dark legs:

This picture shows what appears to be a fairly dense covering of pale hairs on the eyes

Moving on to the more botanical side of things, the Cheilosia above is feeding on a Creeping Buttercup flower, Ranunculus repens (L.).

The Creeping Buttercup is a herbaceous, stoloniferous perennial growing to 50 cm tall. There are many named subspecies. It has both prostrate running stems, which produce roots and new plants at the nodes, and more or less erect flowering stems  arising from a short stout "caudex" with a rosette of leaves. The basal leaves are divided into three broad normally stalked leaflets 1.5–8 cm long, shallowly to deeply lobed, borne on a 4–20 cm long petiole; leaves higher on the stems are smaller, with narrower leaflets. The leaves may be white-spotted. Both the stems and the leaves are finely hairy. The flowers are bright golden yellow, 2–3 cm diameter, usually with five petals. The nectaries are easily seen as tiny pockets at the base of the petals. The fruit is a cluster of achenes 2.5–4 mm long. It grows in fields, pastures, woods, gardens, parks, roadsides and wasteland and prefers wet soil.

Useful ID points are the spreading (not reflexed) sepals, the grooved stems and the stalked (petiolulate) terminal lobe of the trifoliate leaves. Interestingly there have been no reports of a mycorrhizal association.

Like most buttercups, Ranunculus repens is poisonous, although when dried with hay these poisons are lost. The toxin protoanemonin (apparently a break-down product of ranunculin) is not very stable and loses its potency when dry, so buttercup is not generally toxic in hay. The taste of buttercups is acrid, so cattle generally avoid eating them. The plants then take advantage of the cropped ground around it to spread their stolons.

Creeping buttercup spreads by seed and by long branching stolons that root at the nodes, forming new plants (ramets). The stolons may also regrow from cut portions to some extent. In more established woodland and grassland communities, this plant increases mostly through stolons unless the soil is disturbed. In dry conditions, flowering and seeding is more prevalent and in wet conditions, stolons are more plentiful. Seeds can germinate and seedlings can grow even under water-logged conditions. The plant is also said to be spread through the transportation of hay, implying that the seed may be present, I would imagine!

The plant is a serious invasive weed in places like North America and New Zealand. Here is a link to a useful Canadian paper on the biology of this minor threat to their ecosystems and agriculture.  http://pubs.aic.ca/doi/pdf/10.4141/cjps90-135

One of the reasons creeping buttercup is so competitive is that its stolons respond to the environment. Under favourable conditions, plants form more stolons through branching. However, when nitrogen or water is limiting, stolons tend to be longer and un-branched allowing longer distance “sampling” of a number of potential sites until more suitable locations are found. When favourable conditions are discovered, stolon branching resumes, allowing rapid local colonization to take advantage of the available resources. In general, short stolons are produced in dense turf and much longer ones appear in open fields or woodlands.

Depending on the temperature, creeping buttercup either overwinters as a rosette or dies back to ground level. In either case, the nutrients stored in the short swollen stem produce rapid growth in spring, between April and June. Stolons grow from the leaf axils in spring and summer and growth peaks in late summer. Stolons connecting parent and daughter plants usually die off in autumn, leaving the plantlets separate.

Flowers can appear from March to August with seeds soon after. Each plant produces from about 20 to 150 (this may be an over estimate) seeds. Seeds can remain viable in the soil for at least 20 years, and up to 80 years, especially under acid or water-logged conditions. Seeds are dispersed by wind, water, birds, farm animals, rodents, and other animals by adhering to them with the hooked seeds. They exhibit dormancy and also sustained viability in the seedbank.

Excessive contact with the sap of the plant can cause skin blistering in humans, and various toxic effects in cattle if they eat it in excess because they there is little else and they are hungry. Unfortunately, livestock occasionally develop a taste for buttercup and consume fatal quantities.

The age of meadows up to 200 years old can be roughly estimated by the number of plants in 100 that have extra petals in their flowers - you get about 1 plant with flowers with extra petals for every 7 years old it is claimed.  http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2729631/ Mentioned in notes of nature. However the correlation coefficient is only moderate, in my view. This flower, photographed by chance a little further along the woodland path at Bod Petrual, turned out on closer examination to have 8 petals as far as I can see! I can just see 1 of the 3 sepals below I think.

and this one has 6 petals.

This on the other hand is another toxic plant, the Meadow Buttercup, Ranunculus acris, with a more finely dissected basal leaf. In this species there tend to be 5 (3 - 7) leaflets and in addition, unlike in the Creeping Buttercup, the middle (or each?) leaflet is un-stalked, giving a typical palmate rather than trifoliate appearance. The BSBI plant crib is very useful here: http://www.bsbi.org.uk/Ranunculus_Ranunculus_Crib.pdf

There is a photo below that of the characteristically even more dissected stem leaf. There were several scattered plants, in amongst or separated from the  Creeping Buttercup, apparently it appears at random. There were very many fewer of this species, and I didn't happen to see any Cheilosia on them.

The very different, almost linear, un-stalked stem leaves of Ranunculus acris (L.) acris, the only subspecies found in the UK - although there are three different races!

The fairly common confusion species to Ranunculus repens is the Bulbous Buttercup, Ranunculus bulbosus, of drier grasslands, which has sepals that are reflexed in full flower. I saw this behind the dunes at Warkworth last week I believe.

In the Meadow Buttercup, the flower is similar to the flower of the Creeping Buttercup, with un-reflexed (spreading) sepals, but the flower stalk is, by contrast to the Creeping Buttercup, ungrooved. Another feature is the chromosomal number. Ranculus repens is generally a tetraploid plant (N = 32) based on N = 8, while Rancunulus acris is also a tetraploid (N = 28) based on N = 7.

There were plenty of other plants growing in profusion, and a few were even in flower. It was particularly nice to see the Cuckoo Flower, Cardamine pratense, so long after all the ones in Kent are long over.