Summer evenings and stiff necks ...

Purple Hairstreak (Favonius quercus)

The Purple Hairstreak (F. quercus) is our commonest hairstreak, and may be located in oak woodland throughout southern Britain, and more locally elsewhere. It is often difficult to locate, due to its habit of flying high in the tree canopy, where it feeds on honeydew; groups of several individuals chasing one another is not an uncommon sight. However, the adults are occasionally seen feeding and basking at lower levels, on various small trees, shrubs and bracken. This butterfly is found across southern England and Wales, with scattered colonies further north. It is also found in parts of Ireland, mainly between Wicklow and South Kerry.

It is primarily found in woodland containing oak trees, the foodplant of the larva. However, the species can be found in any location where oaks occur, including lanes, parks, gardens, and other urban areas. The primary larval foodplants are Pendunculate Oak (Quercus robur), Sessile Oag (Q. petraea) and Turkey Oak (Q. cerris). Evergreen Oak (Q. ilex) is also used.

Eggs are laid singly (or less commonly, in groups of 2 or more), usually at the base of a plump oak bud, or cluster of buds, but can also be found on an adjoining twig and at various heights. They are laid on branches that are sheltered and receive full sunshine - such branches are therefore on the southern side of the tree. There also appears to be a preference for solitary trees, such as those found at the edges of woods, or those that form part of a hedgerow. Eggs are also most-often found on relatively mature trees (since these have the plumpest buds) on branches that are twisted and gnarled. Eggs are relatively easy to find in suitable locations during the winter months before the oak buds burst. Emergence occurs from the last week of June, through July and into August, with adults still being found into September. There is generally a peak at the end of July and early August, or later in Scotland. There is one brood each season.

Check out the oaks near you ...

More at:

www.ukbutterflies.co.uk/species.php?species=quercus

The prophetess ...

Marsh Fritillary (Euphydryas aurinia)

This delightful butterfly, a female pictured above, is one of our most threatened species and has suffered severe declines in recent decades. Although declining throughout Europe, the British Isles is considered one of the few strongholds for this species. However, the reclamation of wetlands and the ploughing up of downland has meant that E. aurinia has now disappeared from many counties and has also suffered severe declines in the British Isles; this butterfly is therefore a priority species for conservation efforts. Although still widespread in some parts of its range, this butterfly is reputedly declining by over 10% each decade. The deteriorating fortunes of this species are believed to be the result of inappropriate habitat management, coupled with the need for sufficient habitat for the butterfly to form meta-populations, where local extinctions can be reversed by recolonisation from neighbouring colonies. It is currently found in southwest England with a small population in northwest England, the islands of southwestern Scotland and the adjacent mainland, and northwest and southwest Wales. It is also locally widespread in Ireland.

On a positive note, aurinia is an easy species to breed in large numbers in captivity and one, which lends itself to reintroduction or establishment in suitable areas where its main foodplant, Devil’s-bit Scabious (Succisa pratensis), grows in some profusion. My late good friends, the respected entomologists Peter Cribb and Peter Taylor, both kept healthy stocks of this species going for well over 25 years and bred thousands of healthy specimens for release purposes in various counties in the south of England. In Sussex, the former Ditchling Common colony originated from this source with the original stock coming from just over the border in Surrey.

Colonies of E. aurinia are known to fluctuate wildly in population density. It may be present in good quantities one year, only for the population to crash dramatically the following season without any apparent reason - before recovering just as unexpectedly. It does not do well in adverse weather conditions and can suffer significantly from the attentions of parasitic hymenoptera during the larval stage. Adults, which typically emerge in the middle of May, reach their peak in early June. In northern Scotland they emerge slightly later. There is one generation each year.

Where it occurs, aurinia uses several different types of habitat, including chalk hillsides, heathland, moorland and damp meadows. A factor common to all habitats is that they are in full sun, their higher temperature aiding larval development. As previously mentioned, the primary larval foodplant is Devil’s-bit Scabious (Succisa pratensis). Field Scabious (Knautia arvensis) and Small Scabious (Scabiosa columbaria) are also used.

On emerging from their eggs the larvae spin a silk web, by binding together leaves of the foodplant, in which they live and feed. Larvae build new webs as they grow and even move to a new plant if necessary. In later instars, the webs can be quite conspicuous. Larvae will also bask on the outside of the ‘tent’ absorbing the sun's rays, where their increased temperature aids digestion. After the third moult the larvae build a dense nest of silk low down in vegetation in which they hibernate. Larvae will emerge from their nest with the onset of spring and can be seen basking in warm sun as early as February. The larvae eventually split into smaller groups, continuing to build silk webs where they bask communally to keep their body temperature relatively high, even on cool days. More-mature larvae tend to feed alone and are often found wandering across open ground looking for their next meal or, eventually, a pupation site. There are 5 moults in total. The pupa (pictured above) is formed head down, attached to a twig or plant stem by the cremaster. The pupa is essentially white, with a beautiful mix of black, brown and orange markings. This stage lasts between 2 and 4 weeks, depending on temperature.

More at:

www.ukbutterflies.co.uk/species.php?species=aurinia

Against the trend …

Agapanthia villosoviridescens

The Golden-bloomed Grey Longhorn (A. villosoviridescens)

The Cerambycidae, the Longhorn beetles, are a very impressive group of insects. The family, which includes some of Britain’s most impressive beetles, currently numbers around 70 species. Many striking examples can be found abroad. They are predominantly beetles that develop in wood, with the adults being active during the spring and summer months. However, A. villosoviridescens is an exception to this rule, developing in the stems of a variety of herbaceous plants including Cardus, Urtica, Angelica, Chaerophyllum, Artemisia, Salvia and Aconitum. The larvae develop in the above-ground plant tissues. They cut off the plant stalk before pupation, create the pupal cells near ground level, and the adults leave the stalks via a newly created exit hole in the side of the remaining stalk. The above specimen, one of four observed, was found sitting on Hemp-agrimony (Eupatorium cannabinum) at a West Sussex wetland site.

My first encounter with this impressive species …

Stoned ...

European Stonechat (Saxicola rubicola)

The European Stonechat (S. rubicola) is a fairly common resident and partial migrant to Sussex. They are associated with two main breeding areas: heathland and downland with gorse and scrub. Ashdown Forest in East Sussex holds about 50-70% of the county total of circa 150-200 pairs; this out of a national population of circa 56,000 pairs. They are typically seen perching on the tops of bushes in otherwise rather open places, with favoured locations being regularly visited.

An attractive bird and one that is always a pleasure to see …

References:

Scott-Ham, M., 2014. European Stonechat. The Birds of Sussex. Thetford: British Trust for Ornithology (BTO) Books on behalf of the Sussex Ornithological Society, pp. 518-519.

Scott-Ham, M., 1996. Stonechat. Birds of Sussex. Sussex Ornithological Society, pp. 424-425.

Black magic ...

Black Guillemot (Cepphus grille)

The Black Guillemot (C. grille) is a very rare vagrant to the coastal waters of Sussex with only fifteen individuals recorded as of 2010. The British population, which is of the subspecies C. g. articus, is the second largest in Europe only to Norway and contains approximately 38,000 individuals (Seabird 2000) out of a European population 100,000-200,000 breeding pairs. Its UK distribution is very biased towards the far north and west, half of the population breeding in the Northern Isles, particularly Shetland; the nearest breeding populations to Sussex are small populations in southeast Ireland and Anglesey.

They typically nest in crevices or cavities between boulders, and occasionally in holes in harbour walls. Diving to feed, their diet is comprised of small bethnic fish and crustaceans.

References:

Hobson, J., 2014. Black Guillemot. The Birds of Sussex. Thetford: British Trust for Ornithology (BTO) Books on behalf of the Sussex Ornithological Society, pp. 346.

Fairbank, R., 1996. Black Guillemot. Birds of Sussex. Sussex Ornithological Society, pp. 347-348.

BirdLife International (2014) Species factsheet: Cepphus grylle. Downloaded from www.birdlife.org on 31st May 2014.

Spring pearls ...

Pearl-bordered Fritillary (Boloria euphrosyne)

This beautiful woodland butterfly occurs in scattered and isolated colonies south-west of a line running between Denbighshire in the north-west to East Kent in the in south-east. There are also colonies in Westmorland and West Lancashire. It is also widespread in central Scotland, but very local or absent in the north and south of the country. In Ireland, it is found in the Burren limestones of Clare and southeast Galway. It is absent from the western and northern Isles of Scotland, the Isle of Man and the Channel Islands. B. euphrosyne survives in West Sussex thanks to carefully managed Sweet Chestnut coppice in several important woodlands which allows the Common Dog-violet (Viola riviniana), the main larval foodplant, to grow in appropriate conditions.

This is the earliest of our fritillaries to emerge. In good years, the butterfly emerges at the end of April in the south. Most adults emerge at the start of May, but may not appear until the end of May in more northerly locations.

B. euphrosyne is typically found in deciduous woodland containing open areas, such as woodland clearings, that provide the right conditions, foodplants and nectar sources for this species to survive. Suitable sites are generally habitable 2 to 4 years after a woodland clearing has been formed, when the foodplants and nectar sources are optimal for this species. However, these sites can quickly become overgrown and, unless there is suitable habitat nearby or regular habitat management undertaken, colonies are often lost.

Larvae feed by day and generally rest in leaf litter, but can also be found, especially after hibernation, basking on dead bracken. They eat the entire leaves, leaving just the stem intact. They will also feed on only the leaf lobes, at the base of the leaf, leaving characteristic feeding damage that can give away the presence of a nearby larva. After moulting for the third time the larva enters hibernation, generally in a dried leaf, emerging in the spring to complete its growth. There are 4 moults in total.

The two images show a male, referable to ab. interligata, Cabeau (1919) + ab. transversa, Vorbrodt (1911) recently found in West Sussex.

More at www.ukbutterflies.co.uk/species.php?species=euphrosyne

On your marks, get set …

Brown Hare (Lepus europaeus)

The taxonomic Order Lagomorpha comprises the hares, rabbits and pikas. The Brown Hare (L. europaeus) is the largest of the British lagomorphs. Since there is no evidence of their presence in Britain before Roman times, it was probably introduced by man. They are widespread on low ground throughout England and Wales. In Scotland, L. europaeus is found on farmland and rough grazing to the far north of the mainland, but is absent from parts of the North West. L. europaeus is replaced by the Mountain Hare, L. timidus, in upland areas of Scotland and central England.

Brown hares generally live in exposed habitats, and they rely on their acute senses and running at speeds of up to 70kph (45mph) to evade predation. Hares do not use burrows, but make a small depression in the ground, known as a form, amongst long grass. They spend most of the day on or near the form, typically moving out to feed in the open at night. Tender grass shoots, including cereal crops, are their main foods. Though generally solitary, hares sometimes band into loose groups when feeding.

Breeding takes place between February and September and a female can rear three or four litters a year, each of two to four young. The young, known as leverets, are born fully furred with their eyes open and are left by the female in forms a few metres from their birthplace. Once a day for the first four weeks of their lives, the leverets gather at sunset to be fed by the female, but otherwise they receive no parental care. This avoids attracting predators to the young at a stage when they are most vulnerable. Foxes are important predators of young hares and where foxes are common there are likely to be very few hares. Adults typically live to 3 or 4 years.

Numbers of hares have declined substantially since the beginning of this century, though they are still locally common animals in many parts of the country. The main reason for this decline seems to be a change in the way modern agriculture is managed. Today's farms are often intensive and specialised, either growing crops like wheat and oilseed rape, or raising livestock for meat and dairy produce. A hundred years ago most farms were varied enterprises. Mixed farms have a patchwork quilt of fields, which provide year-round grazing for hares as well as long crops for them to hide in. Modern cereal farms provide little or no food for hares in late summer and autumn, and livestock farms have few crops for them to shelter. Modern farm machinery and pesticides also kill many hares.

References:

Bjärvall, A. and Ullström, S., 1986. The Mammals of Britain and Europe. Beckenham, Kent: Croom Helm Ltd., pp. 60-62.

Corbet, G. B. and Harris, S., (eds.) 1991. The Handbook of British Mammals (3rd Edition). Oxford: Blackwell Scientific Publications, pp. 154-161.

The Mammal Society (2014). Species fact sheet: Brown Hare (Lepus europaeus). Downloaded from www.mammal.org.uk on 1st May 2014.