Dragonflies and Damselflies at Potteric Carr
Potteric Carr is fortunate in its geographical position in that it embraces the southern / eastern limits of some species, e.g. Common Hawker, and is near the northern limit of species with a southerly distribution, e.g. Emperor Dragonfly. As a result, the Reserve has a larger number of species than would normally be expected for a site of its size. However, whilst some 21 species having been recorded in the last 25 years, the numbers of any one species encountered on any one day will be much lower than may be typically experienced on species’ stronghold sites elsewhere.
The Reserve offers plenty of opportunities for viewing damselflies and dragonflies with a number of small pools offering close views, particularly Loversall Delph and the ponds in Loversall Field. However, the larger water bodies and deep drains are not accessible for reasons of safety and, in the case of the larger water bodies, observer access could cause disturbance to birds, including Schedule 1 birds that may be breeding there. By using binoculars from the hides, it is possible to observe dragonflies often patrolling these areas and ovipositing.
Identification
Like any other group of species, identification features need to be learned but all the species at Potteric Carr can generally be easily identified with a little experience. Binoculars, which close-focus to around 1.5 metres, are now available from a number of suppliers, and are particularly helpful in enabling observers to examine key parts of the insects to aid their identification without the need to net them. A number of pointers to aid identification in the field are included in the text and a free key, which may help with the identification of these insects at Potteric Carr, can be viewed / downloaded
. However, those interested in improving their identification skills should refer to recognised field guides listed below.
Species List
Six species of damselfly and 15 species of dragonfly have been recorded on the Reserve in the last 25 years. Some 18 species are seen regularly each year and, of these, 16 species are known to have bred or are suspected of breeding, based on the criteria given below. The other three species are non-regular immigrant / vagrant dragonflies.
Abundance
The letter at the end of each species’ account, gives relative abundance (estimated peak number on any one day in the appropriate flight season) using the nomenclature:– A = 1; B = 2-5; C = 6-20; D = 21-100; E = 100–500; F = 500+. V is used to indicate an irregular vagrant/immigrant.
Breeding Assessment
Assessing breeding at Potteric Carr can be difficult mainly due to the main water bodies and drains being inaccessible, i.e. for monitoring larvae and observing emergence and collection of exuviae (spent cases following emergence). However, an assessment of breeding is given based on available information using the following codes after the species’ name. Only the code giving the most positive confirmation is stated.
The period in years of the larval stage is given. Where this is a range of years, the actual period at a particular site often depends on the latitude of the site, the larval stage being shorter in the south and longer in the north, but can also depend on the temperature and food availability.
P = Male and female present in suitable habitat; O = Ovipositing observed; Ex = Exuviae found; Em = emergence observed; T = Teneral (newly emerged) insect found.
Damselflies
Banded Demoiselle Calopteryx splendens P
This species was first recorded at Potteric Carr in 1993. It is a species that prefers slow moving streams and it would appear that the main Mother Drain may fulfil this requirement, particularly since its quality was improved in the 1990s. Their flight period at Potteric Carr is from mid / late May to late August. Although damselflies, they are almost as large as some dragonflies, though of more slender build. The males are quite distinctive in electric blue with dark blue bands across the wings. However, the females which are green are much more difficult to locate. A good place to see them at certain times can be from the bridge over Mother Drain and under the railway but they can be encountered almost anywhere. Larval stage: 2 years. C/D
Left male © Allan Parker ARPS and right female © Glyn Hudson
Mated pair © Glyn Hudson
Emerald Damselfly Lestes sponsa T
This damselfly is fairly common at Potteric Carr. They are the last of the damselflies to appear, generally around mid June, and are on the wing well into September. They are often seen perched in deep grass alongside many of the paths, but they can also be observed ovipositing in many of the Reserve’s water bodies. The male is often confused with the Blue-tailed Damselfly. However, the abdomen is longer than the Blue-tailed and the blue is a paler powder blue. A key to identification is that when resting, the wings are normally extended away from the body. Larval stage: 1 year. D
Male (L) and female (R) © Allan Parker ARPS
Large Red Damselfly Pyrrhosoma nymphula T
The earliest of all damselflies to appear, they are normally on the wing from mid/late April. While their flight period is said in literature to extend into August, there are few if any records at Potteric Carr after early July. Though not as numerous as the “blues”, this fairly common damselfly can be found perched on waterside vegetation but can just as easily be seen well away from water, even in woodland. They are equally at home in ponds and muddy streams, habitats that are present at Potteric Carr. The females can appear in one of three forms fulvipes , typica , melanotum , depending on the amount of black on the abdomen (refer to Field Guides). Evidence of mass emergence, a relatively common occurrence in both dragonflies and damselflies, was observed in 1999 when around 90 exuviae were counted at Loversall Delph on one morning. Larval stage: 2-3 years. D
Adult male © Allan Parker ARPS
Female © John Hancox and mated pair © Allan Parker ARPS
Blue Damselflies
General Note:–
There are two predominantly “blue” damselflies present at Potteric Carr, Azure and Common Blue, paradoxically, the former being much the commoner. Care must be taken when identifying them, as they are very much alike to the untrained observer. Reference to field guides may help but the easiest way to separate the males is to look at segment 9 (next to last segment on the abdomen). This is clear blue on the Common Blue but has noticeable black markings on it on the Azure. For the females, the main distinguishing feature is segment 8, where the black marking is ‘Christmas tree’ shaped in the Common Blue whilst being a black square on the Azure. These features are relatively easy to see in the field when insects are at rest. Please note: these characteristics do not necessarily apply at sites where other “blues” may be present!
Azure Damselfly Coenagrion puella T
The Azure is (with the Blue-tailed) the most numerous of the damselflies on the Reserve. They are generally on the wing from early May (or even late April in some years) to mid-August, with the largest counts being end May/early June (estimated to be in 1000s) as has recently been experienced in May 2010. They can be found in all parts of the Reserve, often in tandem ovipositing in many of the water bodies. Larval stage: normally 1 year. F
Female left © Derek Bateson and male right © Allan Parker ARPS
Left mated pair and right close-up abdominal markings © John Hancox
Common Blue Damselfly Enallagma cyathigerum T
Despite its name, this is the least common of the blue damselflies on the Reserve being seen in 10s rather than thousands! They emerge at about the same time as the Azure, or perhaps a few days later, but are on the wing later until mid-September. They can be found almost anywhere where the Azure is present but tend to be more numerous in southern parts of the Reserve. Larval stage: 1-4 years. D/E
Adult male left and right close-up of abdominal markings © John Hancox
Left, normal female © John Hancox and right female of the 'brown' form © Peter Dawson
Blue-tailed Damselfly Ischnura elegans T
Very common, with similar numbers to the Azure Damselfly. Their flight period is similar to the Common Blue, extending from early/mid-May to mid-September. They can be active in a wide range of weather conditions and appear to be able to tolerate some degree of water pollution. Whilst they can be seen in many parts of the Reserve, the most likely sites are near the drains, around small ponds and on the margins of most water bodies. The females can appear in any of five colour forms but they initially appear in one of two forms, mainly determined by the colour of the thorax and segment 8 of the abdomen; rufescens (pinkish-red form) which become yellowish-brown after a few days giving a mature form infuscans-obsoleta ; and violacea (violet form) which can mature either into the typica form (colouring similar to the male) or the infuscans (green phase) (refer to the Field Guides for more details on these colour forms). Larval stage: 1-2 years. F
Adult male left and immature male right both © Allan Parker ARPS
Female form rufescens left and right female form violacea both © Allan Parker ARPS
Mated pair (female form infuscans-obsoleta ) © Allan Parker ARPS
Red-eyed Damselfly Erythromma najas T
There was an unconfirmed record of an immature on Mother Drain in May 2011. In recent years, this species has been gradually spreading north and west and has been recorded at a number of sites mainly to the east of the Reserve. They tend to perch on floating vegetation, particularly water lily leaves, but they do use other plants with floating leaves such as
Potamogeton natans
and Amphibious Bistort
Persicaria amphibia
, and in some cases mats of floating algae. The damselfly itself is most likely to be confused with the Blue-tailed Damselfly, the most noticeable difference being the eyes, red in the male and browny-red in the female. A key feature in males is that segments 9 and 10 at the end of the mainly black-green abdomen, are all blue (cf. the Blue-tailed where the blue is only on segment 8). Females are very similar to female Blue-tails but slightly larger and have very short antehumeral stripes. One to look out for!
Red-eyed Damselfly Erythromma najas immature © Rob Mokryj
Dragonflies
Hawkers
Hairy Dragonfly Brachytron pratense
The appearance of this species is extremely variable at Potteric Carr. Since the first sighting in 1998, they have been seen most years but often only single sightings. They are normally seen only briefly, flashing through an area on a sunny day and going to rest out of sight when the sun goes behind clouds but in May 2010 there were a number of sightings including one at rest which was photographed. Though superficially similar in appearance to the Southern Hawker but smaller, confusion is avoided since it is the earliest hawker to appear, its flight period being in May / June, normally before the Southern Hawker has emerged. Potteric Carr is at the edge of the species’ range but it has spread north in the last 20 years, a process which continues. Larval stage: normally at least 2 years. A
Male left and female right © Glyn Hudson
C ommon Hawker Aeshna juncea O
This species is the least common of the larger hawkers at Potteric Carr with a few sightings each year, often in September, when they may be seen anywhere on the Reserve. It may be a sporadic breeder, evidence being a pair seen mating in 2001 and a record of an ovipositing female in the early 1990s. Larval stage: normally 3-4 or sometimes more years. B
Male © Glyn Hudson
Migrant Hawker Aeshna mixta Em
Until the 1980s, this species was generally confined to the south and east of England; before that it was mainly a summer migrant to Britain, hence its name. There was an early record of one at Potteric Carr around 1980, but such has been the expansion of the range of this species that it is now much the most numerous of the hawker dragonflies on the Reserve.
They are seen at Potteric Carr from late July (though more often early August) to November in most parts of the Reserve and it is quite possible that on an average day in favourable conditions as many as 20+ could be encountered. Peak numbers usually occur in late August/early September when any sheltered clearing can hold a number of them hawking. Occasionally, much larger numbers can be encountered due to immigrants from the continent and one occurrence was in 1998 (on the day of the annual autumn barbecue!) when it is estimated that hundreds were on the Reserve. They are somewhat smaller than other hawkers but this is often difficult to judge. However, the blue or pale area on the underside of the thorax and segment 1 of the abdomen can often be clearly seen from below when they are in flight and also when they are resting.
Proof of breeding includes one “drying out” at Loversall Delph in 1996 and many records of mated pairs. Larval stage: 1 year. C/D
Left immature male and right adult male © Allan Parker ARPS
Left male hovering © Glyn Hudson and right male close-up showing diagnostic markings © Allan Parker ARPS
Left emerging and right female preparing to lay eggs © Glyn Hudson
Southern Hawker Aeshna cyanea O
This species is a relatively common sight at Potteric Carr from end June to end October but the number of individuals varies from year to year. They are seen patrolling their territories in many parts of the Reserve, notably along Loversall Bank and over the many drains, and can often come to “inspect” anything or anyone that intrudes into their territory! Ovipositing females have been recorded at ponds on a number of occasions. They are often confused with the Common Hawker despite the colour differences, but key features are the very prominent green/yellow antehumeral stripes on the thorax of this species, and the blue on segments 9 and 10 which form two blue bands on the Southern Hawker (being pairs of spots on the Common Hawker) giving the impression of a blue tail. Larval stage: 2 years. C
Left male © Derek Bateson and right female © John Hancox
Female close-up showing antehumeral stripes © Allan Parker ARPS
Brown Hawker Aeshna grandis O
This species appears from early July and is on the wing into early October. It can be seen over many of the water bodies. There have been a number of records of ovipositing, but there are few records of individuals at rest – they are mostly seen hawking several metres up in the air mostly, but not necessarily, over water or marsh. It is perhaps the easiest of the hawkers to identify the overall impression being of a brown body with wings which are suffused with brown glinting in the sunlight. Larval stage: 2-4 years. M
Left © Allan Parker ARPS and right © Glyn Hudson
Female egg laying © Allan Parker ARPS
Emperor Dragonfly Anax imperator Em
This species is the largest dragonfly in Britain and is on the wing from early June (or exceptionally late May) until early September. They were first recorded at Potteric Carr in 1989 since when the numbers have increased until it is fairly common in most years. Proof of breeding was first obtained in 1996 when a female was photographed “drying out” at Loversall Delph – today, it is common to see exuviae on reeds, particularly in the ponds in Loversall Field, where they are also often seen patrolling and ovipositing. In flight the impression is of a very bulbous head / thorax, which is green in both sexes, and an abdomen with a prominent black stripe down it which is usually easy to see when the insect is at rest. In flight, the abdomen often droops at the end. Larval stage: normally 2 years but sometimes 1 year. Em
Female left and male right © Glyn Hudson
Left female ovipositing © John Hancox and right exuviae © Allan Parker ARPS
Male in flight © Glyn Hudson
Lesser Emperor Anax parthenope
There was an unconfirmed sighting of this species in 2006 when many were reported elsewhere in the region. V
Golden-ringed Dragonfly Cordulegaster boltonii
A female was recorded in 1990 apparently ovipositing – this is some considerable way from its normal habitat (probably in the streams on the Pennine slopes). Larval stage: 2-5 years. V
Left, adult male and right adult female © Glyn Hudson
Skimmers and Chasers
Four-spotted Chaser Libellula quadrimaculata T
This species is on the wing from early May (or sometimes even late April) and is present until early August. The species would appear to have increased in numbers markedly during the 1990s and, from mid-May to late-June, they are a fairly common sight. The main impression is of a mid-dark brown, medium sized dragonfly with bronze coloured wings. They are very active patrolling / feeding / mating over most of the water bodies. The ponds in Loversall Field are a good place to view, where they can often be seen disputing territory when they will attack each other, the clash of wings being clearly heard; they will also often attack other species in their territory, e.g. Broad-bodied Chasers – and will even “have a go” at the much larger Emperors! Larval stage: 2 years. D
Female © Allan Parker ARPS and male © Glyn Hudson
Form praenubila © Glyn Hudson
Female appendages (L) © Allan Parker ARPS and male appendages (R) © John Hancox
Broad -bodied Chaser Libellula depressa C
This species was recorded only sporadically until 2000. That year was a turning point since more individuals were seen and, since then, this dragonfly has become established on the Reserve, though in relatively small numbers. They appear around mid-May, the bright blue abdomen of the males drawing attention as they patrol over various water bodies, such as the ponds in Loversall Field. They can also be seen, especially early in the season, well away from water.
This robust-looking species has a broad, flattened abdomen (blue in the males and tawny brown in the females and teneral males) with yellow markings down the sides of each segment. Both males and females have dark brown patches at the wing bases. Larval stage: 1-3 years. T
Adult male © Allan Parker ARPS
Left adult female and right female in flight © Glyn Hudson
Bl ack-tailed Skimmer Orthetrum cancellatum T
This is another species that spread north during the 1990s and was first recorded at Potteric Carr in 1994. In 1995, a male was seen regularly at Willow Marsh where, as the marsh was being developed, there were extensive areas of bare margins to a small water body. Numbers have increased since then and they can be encountered in many parts of the Reserve, though often it is teneral insects that are seen, sightings of adults being scarce. Their preference for newly established water bodies was evidenced in 2006 when many hundreds (which may have been immigrants to the area) were seen over the newly developing marshes at Huxter Well, numbers that have not be encountered since then.
The males of this species are sometimes confused with the Broad-bodied Chaser males since they both have blue abdomens and observers should refer to the field guides for help in separating them. Briefly, the male abdomen is much slenderer and longer that the Broad-bodied Chaser and is powder blue with a dark tail. The females and immature males have a yellow slender abdomen with two prominent black lines on the sides of each segment. The wings are clear, i.e. no dark patches at the base. They are a fast, low flying, highly active species and are commonly seen perching on open ground or muddy banks, for which they have a particular preference. They will also perch on low vegetation, dead trees, paths, etc. Larval stage: 2-3 years. C/D
Immature male left and adult male right both © Allan Parker ARPS
Mated pair © David Round
Darters
General Note on Darters
The presence of three species of darters can cause problems with identification, particularly the females, the male coloration normally making them easy to distinguish, except as tenerals.
In all three species, the females are generally pale to dark yellow in colour and appear very much alike. Common Darters can be separated from female Ruddy Darters and Black Darters quite easily by observing their legs which are black with a white/creamy line along them (generally easy to see, especially through binoculars). Both Ruddy Darters and Black Darters have legs that are all black. The main difficulty then is between female Ruddy Darters and Black Darters. The female Black Darter has a black triangle on the thorax, whereas this is a “T” shape on the Ruddy Darter. The Black Darter is also somewhat smaller (both wing span and body length) than the Ruddy Darter, but this is very subjective and difficult to judge even by experienced observers.
Common Darter Sympetrum striolatum T
This species is by far the most common dragonfly on the Reserve, being measured in thousands at their peak. Their flight period at Potteric Carr starts in mid-June and continues well into November, when they can still be seen assiduously ovipositing in any small piece of water, even in puddles or wheel tracks in soft ground! They can be seen almost anywhere on the Reserve perching on fences, walls, tree stumps, low vegetation, stones, rocks, on the ground, and even on people, on hats or heads! They readily return to the same perch after being disturbed. The males are an orangey-red whilst the females (and immature males) are various shades of yellow; see the general note on “darters” above. Towards the end of their life, both sexes gradually lose their colour the males becoming brownish with a hint of red, and the females olivaceous. Larval stage: 1 year. E/F
Left, adult male and right adult female © Allan Parker ARPS
Left immature female and right close-up showing compound eyes © Allan Parker ARPS
Left emerging dragonfly with exuviae © John Hancox and right mated pair © Allan Parker ARPS
Right immature male showing pale (clear) pterostigma © John Hancox and left a male showing blue pterostigma © Allan Parker ARPS
Ruddy Darter Sympetrum sanguineum Ex
This species was first observed at Potteric Carr in 1995 since when it has become reasonably common, particularly at the western end of the Reserve but they are substantially outnumbered by Common Darters. However, they are probably under-recorded, particularly the females. The flight period at Potteric Carr extends from mid-June to early October. Peak numbers tend to occur in mid/late August, but even into September there are usually good numbers still about. However, they appear to be more numerous in some years than others. The male is a small blood-red dragonfly with a noticeably clubbed abdomen and is unmistakable. For females, see the general note on “darters” above. Larval stage: 1 year. B
Left adult male © Glyn Hudson and right female © John Hancox
Black Darter Sympetrum danae T
Appearing from mid July, this species is somewhat of an enigma or perhaps more accurately a “scarlet (black!) pimpernel” at Potteric Carr. This is because the Reserve is probably only suboptimal for this species being near the edge of its main range. They appeared to be more common in the late 1980s but, currently, are seen only in very small numbers if at all in any particular year. They are also “wanderers” and those seen could easily have wandered from other breeding sites!
The mature males are distinctive, being the only all black darters on the Reserve and should be easy to recognise. They have a short, clubbed abdomen (shorter even than the Ruddy Darter). Immature males are similar to females but with more black on the clubbed abdomen. Their flight is erratic and of short duration, and they perch on vegetation, fences, etc., near shallow water. For females, see the general note on “darters” above. Larval stage: 1 year. B
Left 'fresh' adult male © Glyn Hudson and right 'over-mature' adult male © Allan Parker ARPS
Female © Allan Parker ARPS
Red-veined Darter Sympetrum fonscolombii V
This species is normally an immigrant to Britain, though small, short-lived breeding colonies can/do occur. In 2006, there was a major immigration of this species into Britain and there were over 50 sightings on the Reserve over a period of a few weeks. There were reports of newly emerged individuals being seen in 2007 indicating that there may have been local breeding but this is unconfirmed. This species, particularly tenerals, can appear very similar to the indigenous Common Darters and the observer should refer to the field guides to be sure of identification. Key features are the wing veins, red in males, yellow in females and the undersides of the eyes which are blue. Larval stage: 1 year, but in southern Europe two generations can be produced in a single year, which means that those migrating from there into Britain in spring can produce a second generation in Britain in the late summer. Those seen on the Reserve in 2006 would be the progeny of this second brood.
Left adult male and right adult female © Glyn Hudson
Immature male © Allan Parker ARPS
Flight times
Early and late dates for 2011 together with the earliest and latest sightings recorded at Potteric Carr and the mean date based on the period 2000 to 2011 can be found
References
The following is a list of field guides (*) and other references.
Corbet, P. S., Brooks, S., Dragonflies , New Naturalist, 2008
Brooks, S., Lewington R., Dragonflies & Damselflies of Great Britain & Ireland , British Wildlife Publications, 1997 (2002)*
Powell, D., A Guide to the Dragonflies of Great Britain , Arlequin Press, 1999*
Smallshire, D., Swash, A., Britain’s Dragonflies , WildGuides, 2010*
Cham, S., Field Guide to Larvae & Exuviae ( Volume 1, Dragonflies, 2008, Volume 2, Damselflie s, 2009), British Dragonfly Society
Text © John Hancox 2010