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Showing posts from April, 2019

Duke of Burgundy in Dorset: what your tweets tell us ...

Duke of Burgundy in Dorset: what your tweets tell us ...

The 'Duke' used to be known as the Duke of Burgundy Fritillary but although its wing patterns resemble those of the fritillaries it is not a member of the same family, it is the only British member of the metalmarks (Riodininae). Like so many of our butterfly species it has suffered greatly from loss of its preferred habitat and is now quite scarce. It likes west facing chalk or limestone grassland habitat and whilst there are still suitable sites like this in Dorset there seems to be only one publicly available location where the Duke of Burgundy can be seen. The larvae food plants are primrose and cowslip and so it also used to thrive in coppiced woodland but the decline of active coppicing has seen many colonies die out. The Duke of Burgundy flies in a single generation from early May until mid June but, with just sixteen records in the Nature of Dorset database for 2017 and 2018, we do not have much to go on. The repor…

Holly Blue in Dorset: what your tweets tell us ...

Holly Blue in Dorset: what your tweets tell us ...

The holly blue is the most likely blue butterfly you will see in your garden; that is if you have a garden and where that garden is of course! It favours shrubby areas including woodland but it is well suited to parks, churchyards, gardens and the like. It has two broods each year and the early females lay their eggs of the flowers of holly whilst the second brood females lay their eggs mainly on ivy. Numbers seen each year vary considerably. They are subject to paratisation by a species of wasp, Listrodomus nychemerus, and if there are a lot of holly blues then the wasp will do well and reduce the population of the holly blue but then with less holly blue caterpillars to lay eggs in to the wasp declines meaning the holly blue recovers and so the cycle goes on.  The first brood of holly blue emerge quite early in the year, as early as March in good years, and they fly until the end of May or early June. After a short gap the second broo…

Adonis Blue in Dorset: what your tweets tell us ...

Adonis Blue in Dorset: what your tweets tell us ...

Living here in Dorset it easy to forget that the Adonis blue is one of Britain's rarest butterflies as there are times in summer on some chalk downs where the most common blue butterfly you will see is the Adonis; there are certainly three reasons why this is so. Firstly, the Adonis blue is primarily a European species and we are right at the northern edge of this butterfly's range and it would struggle to survive any further north. Next, Dorset has a substantial amount of the specific chalk downland habitat it requires to survive and lastly considerable conservation effort goes in to managing the ideal habitat requirements they need of short, grazed, flower rich turf with lots of horseshoe vetch.  The Adonis blue has two broods each year. The first emerges in mid May and flies until the end of June and then the second brood emerges in early August and flies until the end of September. There are sixty two reports of Adonis in t…

Chalkhill Blue in Dorset: what your tweets tell us ...

Chalkhill Blue in Dorset: what your tweets tell us ...

Yes, the chalkhill blue is only found on chalk hills; well, include limestone hills as well as they are both calcareous in their formation. I confess that although I try not to have 'favourites' the chalkhill blue to me is a most beautiful insect and I never tire of seeing them but sadly they have declined, like many other species, due to habitat loss. Much chalk grassland was ploughed for crops during the second world war and then the coming of myxomatosis in the rabbit population in the 1950s saw less grazing of grasses to provide the short sward this butterfly needs. Nevertheless there are a number of populations throughout Dorset although some are small and struggling to survive. They need horseshoe vetch for their larvae to feed on and this is quite widespread in the county so given that the right conservation measures are in place hopefully the chalkhill blue is safe. The chalkhill blue has a single brood each summer a…

Common Blue in Dorset: what your tweets tell us ...

Common Blue in Dorset: what your tweets tell us ...

Not so long ago, if you saw a blue butterfly in the countryside you would have to think "Why is that NOT a common blue?" Living up to its name it was certainly the most common of the blues but that seems to have changed in the last couple of years with its numbers seemingly much lower now; in places Adonis blue and silver-studded blue seem to outnumber the common blue. The common blue can be found in a wide range of habitat types from flower-strewn grassland and meadows, hedgerows, woodland glades, heathland, parks and occasionally gardens. Generally double brooded down here in Dorset in good years they are known to have three broods meaning they can be seen from May into October and sometimes even later; there is a gap in June between the first and second broods. We have fifty eight records for 2017 and 2018 in the Nature of Dorset database and there are records for almost every week from week 16 in late April to week 44 at …

Brown Argus in Dorset: what your tweets tell us ...

Brown Argus in Dorset: what your tweets tell us ...

The brown argus is another blue butterfly that is not blue; it is a member of the family hesperiidae. The problem with the brown argus is that it is very like the females of some other blue butterflies, especially the female common blue with which it shares habitat preferences and so it may be either under recorded or even over recorded through misidentification. It is, however, a much more consistent brown colour (if that makes sense) and the dots along the wing are very distinct orange rather than also part silver and black. That is very well if the butterfly is stationary bit what if it is in flight? In flight the underwing of the brown argus is silvery grey whereas the common blue has a darker, more blue underwing. Easy ...? The brown argus has a preference for common rock-rose as its larval food plant and rock-rose is a plant of chalk and limestone grassland so if there is no rock-rose then think 'common blue'. The books s…

Silver-studded Blue in Dorset: what your tweets tell us ...

Silver-studded Blue in Dorset: what your tweets tell us ...

With the silver-studded blue being quite common on the heaths of Dorset it is easy to forget that nationally this is a rare species. It is predominantly a heathland specialist and heathland is restricted to mainly central southern England which means the silver-studded blue is a local species. The loss of heathland habitat since the war means the silver-studded blue has declined in numbers overall but where favourable conditions are found it can occur in significant numbers. Single brooded it is seen mainly in July and early August. We have forty seven reports for 2017 and 2018 combined in the Nature of Dorset tweets database which shows first emergence in week 22 which is mid June and the bulk of records occur in June. There are reports for nine consecutive weeks through until week 31 early in August and peak records come in week 23 and 24 so it seems that the silver-studded blue flies a little earlier than the text books indi…

Small Blue in Dorset: what your tweets tell us ...

Small Blue in Dorset: what your tweets tell us ...

The small blue is certainly small, it is the smallest of our British butterflies, but it is not blue; both sexes are brown with the male being a darker, bluish brown. Although somewhat plain I think they are a delicate and quite attractive little insect. They have a preference for calcareous grasslands where kidney vetch and horseshoe vetch are present; the female lays her eggs only on kidney vetch. The males spend a lot of time resting on bushy vegetation ready to ward off other males whilst waiting patiently for a female to come within range. Because of their lack of activity and their small size they can be easily overlooked but, in any case, they are not a common species although they seem to be doing quite well in Dorset. Small blue fly from mid May until the end of June and then often have a second brood in late July and August. The reports for 2017 and 2018 from Dorset tweeters surprisingly shows two records for week 16 at the en…

Small Copper in Dorset: what your tweets tell us ...

Small Copper in Dorset: what your tweets tell us ...

Despite its vibrant orange (or copper) colouring the small copper is a member of the hesperiidae, or blue butterfly, family. It is an active butterfly and one happy at operating near ground level and so it is easy to see. It has three broods each year so there is rarely a time from April to October when it cannot be found. The small copper is most at home in sunny locations whether that be grassland, heath, woodland rides, hedgerow banks, disused railways, parks or gardens; it is a frequently recorded species here in Dorset especially as it is quite distinctive in appearance too. There are sixty two reports of small copper in the Nature of Dorset database for 2017 and 2018 combined. True to form the first emerge in early April (one was even seen in the last week of March in 2019) and then there are records for most weeks right through until week 44 at the end of October; there are also a couple of records from November too. There is a…

White-letter Hairstreak in Dorset: what your tweets tell us ...

White-letter Hairstreak in Dorset: what your tweets tell us ...

Any species that is totally dependent on another is vulnerable should its host encounter difficulties and so it was with the white-letter hairstreak whose dependance on elm has seen its population levels fall dramatically since dutch elm disease wiped out most of the elms from the English countryside in the 1970s. Fortunately, diseased elms can produce new growth from their roots and survive until they reach a reasonable height and this has enabled the white-letter hairstreak to survive as a species and it is thought that in recent years its numbers may even be increasing, possibly due to climate change. The white-letter hairstreak has a short flight period from the beginning of July until mid-August. The reports we have in the Nature of Dorset records database for 2017 and 2018 however show emergence in week 25 in late June and last just four weeks until week 28 in mid-July with no records for August at all. This variance …

Purple Hairstreak in Dorset: what your tweets tell us ...

Purple Hairstreak in Dorset: what your tweets tell us ...

The purple hairstreak is quite common in oak woodland but that does not mean you will frequently come across them. They are small, dark coloured butterflies that spend virtually all of their time in the upper canopy of oak and ash trees and rarely come to our level. They feed on the honeydew produced by aphids and so do not visit flowers hence their high level living. The books say they fly from late June through until early september.  Here in Dorset the weekly reports chart shows emergence in week 25 which is, indeed late June, and then there are weekly reports through until week 33 in early September; the Dorset purple hairstreak is a textbook species! Most reports come early in this flight period in early July. There are reports from twelve Dorset sites so far with Alners Gorse producing the most. Given the dependency on oak trees a couple of the sites listed, Radipole and Lytchett Bay, are a little bit of a surprise to me. Ho…

Brown Hairstreak in Dorset: what your tweets tell us ...

Brown Hairstreak in Dorset: what your tweets tell us ...

When thinking of Dorset's rare butterflies the Duke of Burgundy fritillary or the silver-spotted skipper come to mind as they are both only found at one site in the county but they are quite visible and easily recorded. The brown hairstreak is also only known from one site in Dorset so that makes it equally as rare but as they spend much of their life in the leaf canopy of ash trees they are rarely seen and so easily forgotten. Although the males rarely descend to lower levels the female does as she lays her eggs on blackthorn shrubs and will also feed on the flowers of bramble and thistles but even so, they are not easy to find. The observations we have in the Nature of Dorset database show the brown hairstreak emerging in week 28 in the middle of July and then there are reports nearly every week until week 35 in late August. The text books say that they fly until the end of September but that does not seem to be reflected he…

Green Hairstreak in Dorset: what your tweets tell us ...

Green Hairstreak in Dorset: what your tweets tell us ...

Being the only British butterfly that is green makes the green hairstreak easy to identify but being green it merges with the leaves of the shrubs it rests on and so can be difficult to spot! It is also a small butterfly and quite sedentary spending long periods at rest on shrubbery so it is probably under recorded as far aa the Nature of Dorset database is concerned. They are best observed when they make short flights by watching for where they land and heading for that point. The female is brown rather than green and is even more difficult to find! They are found in shrubby habitats and are particularly fond of heath where they utilise gorse and broom. They are seen from late April through until the end of June. The reports in the Nature of Database show first sightings from week 16 which is the end of April and ties in with the textbook and there are then reports every week until week 26 which is the end of June, again in line …

Orange-tip in Dorset: what your tweets tell us ...

Orange-tip in Dorset: what your tweets tell us ...

The orange-tip is one of the heralds of spring. Single brooded, it usually emerges in April and can be seen into June but they are at their peak in May. The male is unmistakable with those orange wing tips but the female lacks the orange markings which are replaced with dark grey. The female is often mistaken for other white species as the upper sides of the wing are similar but once settled the wonderfully intricate patterns of the underside are unique to both sexes of the orange-tip. The orange-tip also has a very definite flight movement and once learned also helps to identify them in the field. The orange-tip can be seen along woodland rides and in clearings, in shrubby gardens and along hedgerows where there are flowers present. The female lays here eggs on members of the cruciferae family (cabbages) and they have a particular affinity to cuckooflower and garlic mustard, both of which flower at the same time as the orange-tip flie…

Green-veined White in Dorset: what your tweets tell us ...

Green-veined White in Dorset: what your tweets tell us ...

Although possibly as common as the small white it is far less well-known as as a species outside of 'knowledgeable' butterfly people. It is a widespread species that prefers a slightly more moist range of habitats than the small white so it can be found in damp woodland and field margins, water meadows and river banks but it can still be encountered elsewhere including parks and gardens in towns. Like the small white, the green-veined white lays its eggs on flowers of the crucifer, or cabbage family but it is not a pest of garden or cultivated crops like its bigger cousin the large white. In flight it is difficult to distinguish from the small white but when settled the green-veins in the wings are clearly visible and diagnostic. The green-veined white has similar flight periods to the small white too emerging in April with a brief pause around June time before the second brood being active through until September and Oc…

Small White in Dorset: what your tweets tell us ...

Small White in Dorset: what your tweets tell us ...

The small white is a familiar butterfly in Dorset seen in almost all possible types of habitat including gardens where it is hated as much as the large white but it actually does far less harm than its large cousin. Stating the obvious, the small white is, indeed, smaller than the large white and although having similar markings they are far less pronounced on the small white; the wing tips are more dark grey than black. The small white also lacks the dark wing veins that the similar green-veined white possess. The small white flies from April right through until September and possibly in to October although less numerous at the end of June and beginning of July. For such a common species it is odd that there are only 23 reports of small white in 2017 and 2018 combined in the Nature of Dorset database and so it is difficult to draw conclusions about its occurrence here in relation to the text book flight times but certainly emergence i…

Large White in Dorset: what your tweets tell us ...

Large White in Dorset: what your tweets tell us ...

The large white is one of the most common white butterflies here in Dorset and can generally be seen in good numbers although occasionally an influx of immigrants can mean numbers reach very high levels indeed. Infamous for its caterpillars devouring cabbages, large whites can be seen in gardens, downland and woodland in open countryside and in the middle of towns; it can be seen almost anywhere! The first brood appear in late April and then there is a short gap in late June until the second brood emerge and they can be seen through until the end of September or even longer depending on weather conditions. Despite being common there are only 24 records in the Nature of Dorset database for 2017 and 2018 combined. I think this is partly due to the low number of observers that report butterflies and also because it is common and sometimes though not worthy of a mention. What reports there are show a single sighting in week 10 in early Mar…

Brimstone in Dorset: what your tweets tell us ...

Brimstone in Dorset: what your tweets tell us ...

There can be few more uplifting moments after a long, dark, winter than to see a bright yellow brimstone butterfly fluttering through your garden; a sure sign that spring has arrived! Well, may be not, as the brimstone hibernates and if there is a sunny, mild day in the depths of winter they will emerge for a while before returning to their 'slumbers' when the weather deteriorates again.  Brimstones are somewhat nomadic and individuals will travel far and wide through parks and gardens, along woodland rides, by hedgerows, almost anywhere there are shrubs and scrub. They are also long-lived for a butterfly and having survived the winter they mate in March and then continue to fly in to May and possibly June. The new generation of butterflies then hatch in late July and August. Whilst the male is bright yellow the female is a pale green, almost white, and are often mistaken for large white's even though they have no black mark…

Clouded Yellow in Dorset: what your tweets tell us ...

Clouded Yellow in Dorset: what your tweets tell us ...

The clouded yellow is a relatively common migrant species arriving in Dorset in variable numbers each year and in some years there can be a major influx with clouded yellow being seen just about everywhere along the Dorset coast.. Most arrive in late summer and autumn but it is not unusual to see them much earlier in the year. They originate from north Africa and southern Europe and it is amazing that these relatively small insects can travel such great distances and even cross wide expanses of water to get here. They do lay eggs here and ones laid early in the year may well hatch and add to the immigrant population but the later ones rarely survive the English winter and so there is no real British population. The weekly reports show clouded yellow being seen in Dorset from as early as week 8 in February and small numbers are seen regularly from week 12 at the end of March right through until week 38 in mid September and then the n…

Wood White in Dorset: what your tweets tell us ...

Wood White in Dorset: what your tweets tell us ...

The wood white is a nationally scarce butterfly species that has declined with the general decline in coppicing activities in our woodlands. A few colonies are still fo be found in England, mainly in western and southern locations. It is the smallest of the 'white' family and is a delicate, fragile insect with a skitty, weak flight movement. Although called the wood white and found along woodland rides and clearings it also occurs along disused railway lines and scrubby undercliffs along the south coast. It is such coastal habitat where it occurs in Dorset. It was once found along the disused railway line at Powerstock Common but I believe that, sadly, that colony no longer exists. The wood white flies in late May and early June with a partial second brood in August. The three records from Dorset over the 2017-2018 period are for weeks 29, 30 and 31 at the end of July and the beginning of August which would be second brood insec…

Grizzled Skipper in Dorset: what your tweets tell us ...

Grizzled Skipper in Dorset: what your tweets tell us ...

The grizzled skipper is the smallest of the skippers. It is a very active butterfly and difficult to follow in flight and it rarely visits flowers so it is not that easy to record. They do like to rest on bare patches of soil and that seems to be your best bet to get close to them. Once you get your eye in they are quite distinctive in flight and if you find one settled and it then flies off watch it closely and then you will recognise them when you see them by their flight behaviour. They can be found in a wide range of grassy habitats where the grass is not too long and where there are bare patches so look for them on chalk downs, dunes, heaths, disused railway lines and even in woodlands. They are not common but they cannot be described as rare either and can be fairly numerous where they do occur.  This species can be seen from as early as late March until mid-July and in some years one may encounter a second brood in August. …

Dingy Skipper in Dorset: what your tweets tell us ...

Dingy Skipper in Dorset: what your tweets tell us ...

The dingy skipper can be mistaken for one of the similar day flying moths as it not only resembles species like the Burnett companion it flies and behaves like them too. Once settled identification is easier but the dingy skipper is a very active butterfly, especially on warm days, and finding one at rest can be difficult. Widespread and fairly common in Dorset but perhaps infrequent is a better description? The dingy skipper can be found where common bird's-foot trefoil occurs which its larval food plant. As bird's-foot trefoil is quite common it means the dingy skipper may be encountered on chalk grasslands, heath, coastal dunes, even woodland glades, but sunny downland slopes are where the majority are found. The dingy skipper flies from late April until the end of June and there may be a second brood in good years. That is reflected in the weekly reports chart with the earliest record we have being from week 17 right at t…

Large Skipper in Dorset: what your tweets tell us ...

Large Skipper in Dorset: what your tweets tell us ...

The large skipper is probably the most frequently encountered member of the skipper family. It can be found in grassy habitats which can include roadside verges and open areas and so is vulnerable to over zealous activity by councils! However, it also likes woodland edges, paths and rides where there is tall grass for the female to lay her eggs. The large skipper is also the most frequent visitor of the skipper family to gardens and can benefit from a bit of untidiness where grass is left to grow rather than regularly mown. The reference books suggest that large skippers emerge in early June, reach their peak in July then taper off in August and the weekly reports chart shows that in Dorset this pattern is probably true. Week 21 is the earliest report so far and that is usually the last week of May or the first week of June. Reports continue through until week 28 at the end of July but, as yet, there are no reports for August. The mo…

Silver-spotted Skipper in Dorset: what your tweets tell us ...

Silver-spotted Skipper in Dorset: what your tweets tell us ...

The silver-spotted skipper is confined to chalk grassland where the sward is short and with areas of exposed baked earth; this is often areas grazed by extensively by rabbits. Such habitat is now scarce and the silver-spotted skipper has declined significantly since the end of the second World War and also since the myxomatosis outbreak in the early 1950s. It seems, though, that the remaining populations are at stable levels and it is thought some colonies may be increasing again thanks to careful habitat management. The female lays its eggs on sheep's fescue grass which is very common on chalk grassland.   Favouring warm, sunny conditions the silver-spotted skipper is generally seen in August and in to the early part of September and the Dorset reports would seem to bear this out with reports from week 32 through until week 36; there are less reports in weeks 35 and 36 which may because there are less about by this time…

Lulworth Skipper in Dorset: what your tweets tell us ...

Lulworth Skipper in Dorset: what your tweets tell us ...

The Lulworth skipper is, of course, Dorset's very own butterfly having been discovered on the coastal cliffs near Lulworth Cove (apparently in 1832) and so inheriting its common name from the area. Like its cousins, the small skipper and Essex skipper, the Lulworth skipper's food plant is long grass. Whilst the small skipper is primarily associated with Yorkshire fog and the Essex skipper with cocksfoot the Lulworth skipper is associated with tor-grass and therein lies a problem. I am only working on disparate facts I have picked up over time but it seems the Lulworth skipper is now declining in numbers; it once used to occur on the Purbeck Ridge but has gone from there. Tor-grass is a vigorous plant and there are concerns that other plants and wildlife are suffering as it continues to dominate certain areas and so cattle grazing has been stepped up to try and introduce some control over it. More grazing means less tor-gr…

Essex Skipper in Dorset: what your tweets tell us ...

Essex Skipper in Dorset: what your tweets tell us ...:

The Essex skipper is very, very similar to the small skipper in appearance, habitat and larvae food plant and so it is quite possible that they are very underecorded and are more common than one might think. The main difference in appearance are the antennae; the Essex skipper as black tips that the small skipper does not have. A further clue to telling them apart is that whilst the small skipper is at its peak in June the Essex skipper is at its peak in July and in to August. Small skippers are still about during this time but it means that a 'small' skipper seen in July or August is worthy of closer inspection just in case.

There are just 10 reports of Essex Skipper in the database for 2017 and 2018 combined and these are mainly in July with just 2 in June and 2 in August. This reflects the pattern expected with the later emergence that the small skipper with reports of the Essex skipper from week 26 to week 31.

The 10 r…

Small Skipper in Dorset: what your tweets tell us ...

Small Skipper in Dorset: what your tweets tell us ...

The small skipper is a fairly common butterfly here in Dorset. Apart from the very similar but scarce Essex skipper it is unlikely to be confused with any other species given its shape, size and colouring; it should be easily distinguished from the large skipper when settled. The small skipper is associated with rough grassland where there is an abundance of tall grasses, flowers and scrub. The food plant of the larvae is primarily some grass species, especially Yorkshire fog and creeping soft-grass; Yorkshire fog is quite abundant in many areas of Dorset. The reference books say that this butterfly can be seen from June until early September with the peak in July and this seems to be born out by the weekly reports chart. Apart from one report in week 21 (mid-May) in 2017 the bulk of reports come in weeks 25 to 27 at the later part of June and in to early July. There are then just two reports from later in August. Sadly, there are on…