Hairstreaks

The group of butterflies called the "Hairstreaks" also belong to the family Lycaenidae. There are just 5 species in UK of which 4 are resident in Hampshire. The Hairstreaks get their name from the fine white line or lines on the underside wings resembling a 'hairstreak'.  The Hairstreaks might be considered elusive butterflies in the sense that several of our species are not often seen, at least at close quarters, partly because they are uncommon and partly because they spend much of their time high up in the trees. However all offer the occasional chance of a closer encounter when they come down to seek nectar or in some cases to lay their eggs, which is then all the more rewarding for the observer.

 

Brown Hairstreak - Thecla betulae 

Wingspan: ~35-45mm

The Brown Hairstreak is one of our most attractive hairstreaks and also one of the least common, its numbers having declined as a result of habitat destruction and the loss of traditional species-rich hedgerows. Nationally it is locally distributed as far north as Lincolnshire, but is now confined to just two sites in Hampshire. The Brown Hairstreak has very specific habitat requirements requiring a combination of mature trees, young blackthorn growing in hedgerows or amongst scrub, and flowers for nectar.

Adult Brown Hairstreaks spend much of their time high in the trees (usually ash trees) resting or feeding on aphid honeydew. Occasionally they will come down to feed on flowers such as bramble, hemp agrimony or thistles. The females descend to lay their eggs on blackthorn and can be easily overlooked when crawling deep inside blackthorn bushes looking for suitable egg laying sites. The Brown Hairstreak is a fascinating species, because of the elusive behaviour, rarity and attractive colouration - the females in particular are beautiful insects when freshly emerged, with bright orangy-brown underside, splashes of orange on the upperside forwings and prominent hindwing tails. The male colouration is less vivid on the underside and their tails are shorter. Despite their apparent reluctance to come down from the trees, Brown Hairstreaks can seem completely oblivious to the observer's presence when feeding and will sometimes allow a camera lens to be placed just a few inches away.

When to see: The Brown Hairstreak is our last hairstreak to emerge, the flight period normally commencing close to the end of July and lasting until mid September

Where to see: As indicated there are just two known sites in Hampshire, at Noar Hill and just west of Shipton Bellinger in the far north west of the county.

 

Green Hairstreak - Callophrys rubi

Wingspan: ~27-35mm

The Green Hairstreak is the one UK hairstreak which is more likely to be encountered at close quarters, being found in woodland clearings, heathland, chalk downland and rough scrubby ground where there are plenty of bushes, such as hawthorn, gorse or broom. Its distribution in UK is widespread but patchy. The underside of the butterfly is almost completely green as shown in the photo (and therefore perfect camouflage), the 'hairstreak' in this case being reduced to a row of white dots. The butterfly always rests with closed wings, the upperside being a uniform brown colour which is then only seen in flight. The butterflies (especially males) like to perch on their favourite shrub and can thus be disturbed as one walks past. The larval foodplants include gorse and broom but also bird's foot trefoil and rock-rose.

When to see: One generation per year, from late April until mid/late June.

Where to see: The Green Hairstreak, although widespread, is not common and is usually encountered in small numbers - several on a single visit would be good count. Good sites include Magdalen Hill Down, Martin Down and Butser Hill (Rake Bottom). They are also reported every year from Noar Hill and Stockbridge Down and are encountered occasionally on New Forest heaths where there are plenty of bushes, such as gorse.

 

Purple Hairstreak - Neozephyrus quercus

Wingspan: ~32-38mm

The scientific name for this species includes the word quercus which is Latin for oak - and it is flying around the higher foliage and the tops of oak trees, that one normally sees this species. It is quite common in the south of England and Midlands becoming scarcer northwards, being found in favoured oaks in mature woodlands, along roadsides and even in parkland. Its habit of spending much time resting high up in the tree canopy means it is often overlooked. The males have a beautiful purple sheen on their upper wing surfaces, the purple being confined to parts of the forewing on the female. The butterflies do occasionally descend individually to take nectar from bramble or thistles, as in the photo, and occasionally bask low down with open wings but you will indeed be lucky to see this. It will be no surprise that oak leaves are the larval foodplant.

When to see: There is one generation per year, from early July though to late August

Where to see: The butterfly is widely distributed in the mature woodlands of the county, including the New Forest. Look high in the oak trees for silvery grey looking butterflies (from the underwing colour) with a jerky flight - and avoid neck-ache if you can!  A good time of day to look for this species is late afternoon and even early evening on calm days when they will often take wing around their favourite oaks. Specific good sites include Whiteley Pastures, Alice holt Forest (Straits Inclosure), Pamber Forest and the the Pondhead Inclosure in the New Forest.

 

White-letter Hairstreak - Satyrium w-album

Wingspan: ~25-35mm

The White-letter Hairstreak gets its name from the white letter 'W' clearly visible on the underside hindwing. Whilst the butterfly is locally distributed in England and Eastern Wales, it is not a very conspicuous species, partly because of its absolute dependance on Elm trees (which have been ravaged by Dutch Elm disease) and partly because of its elusive habits, spending most of its time in the tree-tops. Despite the loss of many English Elm trees, the butterfly has shown remarkable resilience and small colonies can survive on single isolated elms and on elm sucker growth in hedgerows, as well as Wych Elm which is more resistant to the disease. They do occasionally come down to feed (as in the photo) and can begin to disperse later in the flight period so may turn up some way from their host trees.

When to see: The flight period typically begins towards the end of June and lasts until late July, although the best time to see them in their Elm tree colonies is between late June and mid July.

Where to see: The butterfly, because of its elusive habits, may be more widely distributed in Hampshire than is evident from records. The butterflies are unpredictable in their habits but mid-morning and again mid/late afternoon seem to be good times to see them flitting around at the tops of elm trees. Most reports of the species being seen nectaring low down (eg on bramble or thistles) seem to be from mid-afternoon through until early evening but as indicated above, they are unpredictable. There are  good colonies on elms on Stockbridge Down (see site feature) and on Peartree Common in Woolston. Small colonies are present in Bentley Wood, the Crabtree Plantation near Basingstoke and Yew Hill. 

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Duke of Burgundy

The Duke of Burgundy also belongs to the family Lycaenidae, but to a different subfamily, and one which is commonly referred to as the 'metalmarks' because of the metal-like resemblance of the wings in some species. The metalmarks are mainly found in tropical climates in South and Central America. The Duke of Burgundy is the only representative of this subfamily in Europe (and UK) and is described below.

 

Duke Of Burgundy - Hamearis lucina

Wingspan: 29-35mm

The Duke of Burgundy is a small but very active spring butterfly, found mainly in areas of chalk scrub or downland where there is some taller vegetation and a plentiful supply of cowslips or primroses which are the larval foodplants. It is however, another species in decline nationally as a result of habitat loss. Formerly the species was not an unusual site in primrose rich woodland clearings, but few such woodland colonies remain now. The males are very territorial and like to perch, looking out for females or to chase off competing males, when they will spiral up in the air together in an aerial duel.

When to see: The Duke of Burgundy is an early species to emerge in mid/late April but the season is quite short, lasting usually until late May.

Where to see: In Hampshire Noar Hill is a good site and often the earliest to report emergence (even mid April in hot years), however numbers can be modest (i.e. a few sightings typically, but you can be unlucky). Butser Hill (Rake Bottom) is also a good site but the species usually emerges here in early May. There are several other sites in Hampshire but some are on private land.