A lonely bird's-nest orchid

On a walk I was leading in Brede High Woods today, we came across one spike of the strange bird's-nest orchid (Neottia nidus-avis), a plant I have never seen in this part of East Sussex before.  It was in an area of shady chestnut coppice in a place where there is large number of twayblade orchids (Neottia ovata).

The twayblade has recently been moved to the genus Neottia, so both plants may like similar conditions.  I suspect they prefer places in Brede High Woods where there is a particularly high lime content in the soil, perhaps due to some earlier human activity.

The bird's-nest orchid is myco-heterotrophic, meaning the roots of the orchid draw nourishment from subterranean fungal mycorrhiza and not from decaying wood and other vegetable material as was once thought.  None of the plant contains any chlorophyll.

Since the turn of the century this species has vanished from many of its East Sussex locations and is now most often found in beech woods on the Downs, especially in West Sussex.  It also is said to prefer wet springs, so it seems that we were lucky to find it in this exceptionally dry season.

Balfour's bramble & small black ants

The earliest of the blackberries  to flower, Balfour's bramble (Rubus nemorosus) is now showing well under the transmission lines across the eastern part of the woods and elsewhere.

This used to be known as Rubus balfourianus, hence the title above and is one of the innumerable microspecies of bramble.  It has very distinctive large, flat flowers attractive to a wide range of late spring insects.  In his book on British Rubi, W. C. R. Watson (1958) says this species prefers damp, often clayey, places and that the fruit have a mulberry flavour.

Also close to the transmission line on the sandy top of the root plate of a fallen tree, I found a few small black ants (Lasius niger)patrolling rather slowly and seemingly aimlessly about. 

Roughly half of them were carrying something

which turned out to be another small black ant worker with tightly curled, legs and antennae tucked in and positionedon its back.  At first I thought this was some sort of predator and prey episode, or that the carried ant might be a corpse.  But when I nudged a pair into a tube, they separated and both seemed in perfectly good health.

The literature says that this species and other ants often do this, but I have read no very convincing explanation as to why.  The most popular theory seems to be that the ants are moving from one nest to another and, for some reason, some of the workers need to be carried.  Perhaps they have a special role that makes them weak and lazy.

More records of rare insects

In recent weeks friends like Dave Monk and Colin Boyd have taken some stunning photos of hitherto unrecorded, and often very scarce, insects in Brede High Wood.

In bluebell time Dave Monk photographed a little moth called the bluebell conch (Hysterophora maculosana).

The caterpillars of this species feed on seeds of bluebell and, whilst it may be widespread where bluebells are abundant, it has rarely been recorded in Sussex.  It is, I think, a good example of the balance of nature.  Although there may be apparently inexhaustible supplies of its food plant (from the moth's perspective), it does not appear to have any significant impact on bluebell populations: it simply takes a modest helping of the available bounty.  Pity Homo sapiens doesn't do the same.

The picture above, by the way, is the only one I can find with the moth on a bluebell.

Colin Boyd has been making many hoverfly discoveries.  The picture below is one of his of the hive bee mimic Criorhina asilica.

The larvae of this species develop in rotten wood with a preference for ancient woodland sites and this highlights the importance, enshrined in Woodland Trust policy, of conserving dead wood as well as living trees.

The photo below, by Dave Monk, is of an ant beetle or checkered beetle (Thanasimus formicarius)

This is a predatory species also associated with dead and dying trees, both coniferous and broadleaved.  The adults prey on the adults of bark beetles (Scolytidae) while the larvae eat the larvae of the bark beetles.

In Sussex the species has been recorded mainly from ancient parks and woods in the west but also from Eridge Old Park in East Sussex.

The adult beetles have a marked resemblance to the large velvet ant (Mutilla europaea) - Google it and you will see what I mean - a species with a formidable sting and therefore one might hypothesise that the colour and pattern is a protective device in the beetle.  However, the velvet ant seems to be so rare, nowadays at least, that any would be predator is unlikely to be familiar with its appearance  (Mutilla has never been recorded from our part of East Sussex so far as I know).  Perhaps the pattern on the beetle activates some atavistic repulsion mechanism in the brain of the insectivore.

Crabs and commas

With the warm and sunny weather the woods continue to burgeon, though it is getting very dry.

Today, following the transmission lines from the east we enjoyed a crab apple tree in full bloom (all fruit trees seem to be full of blossom this year).

There was a good showing of butterflies including brimstones and orange-tips, but no sign of pearl-bordered fritillaries in the places where they used to fly.  The picture below is of an unusually small, and rather worn, comma, well disguised on some freshly sprung hornbeam leaves.

Many of these new leaves have a brief moment when they are nicer than flowers and un-nibbled by caterpillars.  These are aspen:

A spring guided walk

Today I led a guided walk on a 3 mile route through Brede High Woods, which are just coming up to their best.  The bluebells are starting now and this male brimstone butterfly was enjoying their nectar on the bank below the main car park.

We first walked east on the long ride through broad leaved plantations on the old fields once called Sheeplands, Sheep Pound Field and Pear Tree Field.  I had hoped there might be a pear tree in the latter, but we did not see one, though we did see a crab apple about to come into flower.

At the end of the ride we turned south towards Twist Wood where the orpine (Sedum telephium) (see picture below), moschatel (Adoxa moschatellina) and pignut (Conopodium majus) grow among the many other plants that are ancient woodland indicator species.

We continued south to the transmission lines and on to Pond Wood where there were several large patches of soil rooted by wild boar.

There were plenty of butterflies about and in some of the newly cleared areas around the transmission lines we saw many orange-tips, brimstones and peacocks.  We even managed to find an orange-tip egg on a plant of lady's smock.

After this we kept quite close to the northern edge of the reservoir before heading up towards Bonsall's Bridge (TQ799201).  In the scrub in this area we heard several nightingales  in full voice and it is good to know they are back in the woods for the summer nesting season.

Walking through Brede High Wood itself we saw one or two common lizards, then we had a quick look at Holman Wood Field where one of the children found a toad crossing the path.

From here we returned via Brede High Heath to the car park.

The woods were inspirational and will improve as the month goes on and the bluebells reach their full glory while more wildflowers join those already giving a good show.  The songs of the wild birds will also rise to a crescendo. 

What better time to visit these wonderful woods?  Look at the Woodland Trust events list for guided walks:

http://www.woodlandtrust.org.uk/en/our-woods/brede-high-woods/pages/events.aspx?wood=5605

Burrs on a birch trunk

To the south of the Old Wood Yard, not far from the Austford coach house is this fine example of a twin-trunked birch covered in burrs (or burls as they call them in North America).

The causes are explained (sic) in this abstract from CABI:

"The numerous buds that cover the surface of the burr develop from meristematic foci formed in the phloem. The burr phloem is also characterized by the irregularity (waviness) of the elements of its conducting zone and the irregular thickness and distribution of the mechanical tissue. The wood of burrs is distinguished by its curly grain and numerous included bud traces. The rapid growth of burrs and their numerous surface buds are probably caused by local disturbance in the balance of growth substances."

So now you know!

Snowdrops at last

Often in the early months of the year I have looked around the High Woods for snowdrops (Galanthus nivalis).

They are not a native species, but bulbs often get washed down streams, or occur on the sites of old gardens.

Today, however, I found a fine colony in subcompartment 6c on the eastern border of the woods where the long west/east ride reaches Reservoir Lane (formerly Powdermill Lane).  OS map reference TQ 81011 20283.

This isolated group contains many flowers indicating that it has been in situ for some time and is increasing having started, no doubt, as one or more bulbs in garden rubbish thrown over the fence.  It is on the heavy clay soil it likes so, maybe, the colony will spread as one of the alien species that normally attracts no hostility.