Thursday, January 22, 2009

The frost is all over

In my ramblings about East Sussex after the recent hard frosts I have noticed that many larger ivy leaves have turned a buttery yellow as though the plant was variegated.

20090117 Stonelink frosted ivy

It reminded me of the well-known Irish jig The frost is all over and I found a splendid meditation on this in words and music here.

Monday, January 19, 2009

Hairstreaking in the Brede Valley

On Saturday, at the invitation of Butterfly Conservation's Rother Woods project, we went looking for brown hairstreak butterfly (Thecla betulae) eggs in the Lower Brede Valley, East Sussex.  The species has been occasionally recorded in this area in the past and it may simply have been overlooked as it is a difficult butterfly to find as an adult.

Neil Hulme from Butterfly Conservation (Sussex) joined the group and brought an egg on a blackthorn twig so that we all knew what to look for (see picture below).  The egg came from West Sussex and was scheduled to be returned, on its twig, after our field meeting.

20090117 Neal Hulme at Stonelink 010

20090117 Stonelink 004

The eggs are usually laid in the fork of a blackthorn twig as above and look like small, hemispherical pearls.  They remain in situ until the leaves come in spring and, once seen, are fairly easy to find if they are present at all.  There are one or two eggs of moths that can be laid in this position, but they are not of this shape.

We had a good walk round the hedges at Stonelink but did not find any eggs (early days yet) though we did see some impressive wild boar rootings and found a strong colony of the rather scarce hard shield-fern.

20090117 Stonelink 017

Tuesday, January 13, 2009

Brimstone moth caterpillar

At the end of our garden I have an open-ended hanging sleeve trap over an artificial water-filled tree hole.  Today, after about a week of hard frosts, I was surprised to find a small brimstone moth caterpillar inside the trap.

20090113 Opisthograptis luteolata 030

The brimstone moth (Opisthograptis luteolata) is a common species with several generations a year and often there are overwintering larvae, though it is difficult to see what they eat if they are very active like this one.  Normally they feed on the leaves of deciduous shrubs like hawthorn and blackthorn.

Mine keeps casting round the box and the various leaves I have provided, but does not seem to be eating any of them.  Maybe I will just let it go again rather than breed it through.

The caterpillars do, of course, look very much like thorn twigs, though in some areas they are green rather than brown.  The explanation for this dimorphism does not seem to be known, but it is not uncommon in the caterpillar world.

Wednesday, January 07, 2009

Coppicing for butterflies

As part of the Rother Woods Project, sponsored by Butterfly Conservation and others, coppicing has started in Killingan Wood about 200 metres north of our house.

20090107 Killingan Wood coppicing 001a

Most of the wood is very shady since coppicing ceased many years ago and the trees, mostly hornbeam, are now what coppicers call "overstood", that is they have gone far beyond the ideal age for cutting.

The increase in sunlight reaching the ground will certainly have a beneficial effect on early-flowering woodland plants and there may also be an increase in woodland butterflies and some other invertebrates.  Most of the stools should, however, grow up again quite quickly (if the deer do not get at the new shoots) and shade will rapidly return to the woodland floor.  Hopefully there will be plenty more areas of new coppice to which the light demanding species can move.

20090107 Killingan Wood coppicing 009a

The notice above on a tree where the path starts into the wood says the timber will be used for firewood.  This is now getting to be quite a scarce resource in South East England but it was, of course, what many of the coppices were used for in the past.  In a more natural world than our own, unless there were forest fires, trunks and branches of trees would die and fall to be colonised by a myriad of fungi and invertebrates and these, of course, would provide important food resources for birds, bats and other wildlife.  But we can't have everything and, if gas fails to arrive from Russia, I am sure many will be grateful for the short period of respite British fuel wood might be able to provide.

Anyway, being so close at hand, I will have a splendid opportunity to observe exactly what happens after this coppice restoration.