Hairstreaks And Duke of Burgundy (Family Lycaenidae)
Descriptions & images of the 4 Hairstreaks resident in Hampshire and the Duke of Burgundy.
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.
Occurrence (distribution based on 1km squares) and abundance (total population) trend data, extracted from the report "The State Of The UK's Butterflies 2015" published by Butterfly Conservation, is shown for each species and indicates the change in distribution and population during the last four decades (1976 - 2014) at UK national level. All 4 species of hairstreak found in Hampshire have suffered significant declines in distribution, abundance or both, during the last four decades.
Brown Hairstreak - Thecla betulae
Distribution change 1976 - 2014: -49%, Population change 1976 - 2014: -15%
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, with just two core areas 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 (often 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 forewings 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 or egg-laying, 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 until mid-September, although males are not usually seen after the end of August.
Where to see: The largest Brown Hairstreak population in Hampshire is located in the Shipton Bellinger/Cholderton area in the far north-west of the county, with another population in the Noar Hill/Selborne area of east Hampshire, although the butterfly's elusive behaviour makes it difficult to assess the size of these populations. As indicated above, the butterfly often favours Ash trees and Ash die-back disease is affecting both areas (particularly Noar Hill) with potential negative consequences on populations. There are indications that Brown Hairstreak may be present in low density in areas outside these core localities, with eggs discovered on blackthorn in the Andover area and both eggs and adults recorded in the Soberton area of the Meon Valley.
Green Hairstreak - Callophrys rubi
Distribution change 1976 - 2014: -30%, Population change 1976 - 2014: -41%
The male and female Green Hairstreak are similar in appearance and always settle with wings closed. One of the images above shows a female ovipositing on dogwood.
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 above (and therefore perfect camouflage), the 'hairstreak' in this case being reduced to a row of white dots. The butterfly always rests with wings closed, 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 species uses a good variety of larval foodplants including bird's foot trefoil, rock-rose, gorse and dogwood.
When to see: One generation per year, from mid April until early 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 a respectable count. Good sites include Magdalen Hill Down, Martin Down, Butser Hill (Rake Bottom) and Noar Hill. They are also reported every year from New Forest heaths where there are plenty of bushes, such as gorse.
Purple Hairstreak - Neozephyrus quercus
Distribution change 1976 - 2014: -30%, Population change 1976 - 2014: -54%
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. Nevertheless its distribution and abundance at national level has suffered significantly in recent decades. The adult's habit of spending much time high up in the tree canopy, where they feed on honeydew, means they are often overlooked. The male has a beautiful purple sheen over much of the upper wing surfaces, whereas, in the female, the purple is confined to part of the forewing. The butterflies do occasionally descend individually to take nectar from bramble or thistles or bask on leaves, sometimes with open wings. 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 quite 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 Alice Holt Forest (Straits Inclosure), Pamber Forest, Whiteley Walks and the Pondhead Inclosure in the New Forest. An interesting alternative to the main woodland sites is Browndown South (subject to MoD access restrictions) where they can often be seen in the stunted oak trees at eye level or below.
White-letter Hairstreak - Satyrium w-album
Distribution change 1976 - 2014: -45%, Population change 1976 - 2014: -96%
White-letter Hairstreaks always settle with wings closed.
The White-letter Hairstreak gets its name from the white letter 'W' clearly visible on the underside hindwing. The butterfly is considered uncommon, having declined significantly in distribution and abundance in recent decades, but it is locally distributed in England and Eastern Wales and there are indications that climate change may be enabling it to spread northwards. The White-letter Hairstreak is not a very conspicuous species, partly because of its absolute dependence on Elm trees (which have been ravaged by Dutch Elm disease) and partly because of its elusive habits, the adults spending most of their time in the tree-tops. Colonies exist not only in rural locations, such as on Elms in woodland locations or hedgerows (down to single isolated Elm trees or sucker growth) but also where Elms survive in towns and even the suburbs of large cities. The butterflies do occasionally come down to take nectar, for instance from bramble, privet or thistles. They tend to disperse later in the flight period, so may turn up some way from their host trees. The female has the more pronounced 'W' marking and longer delicate tails on the hind wing (see female photo above) which can soon become damaged.
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 butterflies unpredictable, but mid-morning and again mid/late afternoon seem to be good times to see White-letter Hairstreaks flitting around the tops of their host Elm trees, or if you are lucky, feeding at a low level, typically on bramble or thistles. Whilst still very local, the White-letter Hairstreak is now believed to be more widely distributed in Hampshire than previously considered, with a number of new, but isolated sites discovered recently. There is a decent colony of White-letter Hairstreak on Elms on Stockbridge Down with another small colony in Bentley Wood (see site features). I provide map links to two other well-known locations to find the butterfly, namely on a row of elms close to the northern edge of Lakeside North Harbour at Cosham (location here) and on a row of Small-leaved Elms at Peartree Green in Woolston (colony location here). During a period of several years, an enthusiastic observer has visited and compiled a list of many more Elm locations hosting the species in Hampshire and submitted a list to the local branch of Butterfly Conservation. I have not visited many of these locations myself, so simply provide a link to the news page concerned (here), the entry is listed under 1 July 2018. This suggests many other locations remain to be discovered!
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 the UK) and is described below.
Duke of Burgundy - Hamearis lucina
Distribution change 1976 - 2014: -84%, Population change 1976 - 2014: -42%
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 sometimes found in woodland clearings, usually in small numbers, where primrose is then the exclusive larval foodplant. The Duke of Burgundy is another species which has declined significantly in both distribution and abundance at the national level in the last four decades, although most recent data is somewhat more positive and suggests the decline may have been halted and even reversed in some areas, with modest increases in the size of some colonies. 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, typically from mid-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. The butterfly is also found at a number of downland sites, including several locations on Butser Hill, such as Rake Bottom and West Butser. It is encouraging that the species recently seems to be establishing small colonies at a few new locations, mainly in an east-west swathe on the chalk dominated landscape across the middle of the county, such as at Old Winchester Hill and Stockbridge Down. There are also small colonies in a few woodland locations including Bentley Wood (Eastern Clearing) and West Wood (Farley Mount).