Tag: Top 10 Facts

Top 10 Facts: Waxwing

Winter visitor. Waxwings are winter visitors to Britain, migrating here from their breeding grounds in the boreal forest belt that stretches from Scandinavia, through Russia and across parts of North America. The numbers that reach the UK depend on the availability of berries on the Continent. In years where berry crops fail, birds are forced to migrate greater distances in search of food, often reaching our shores en masse.

Irruptions. Given that the winter movements of waxwings are dependent on the amount of food available on the continent, the UK can receive anything from a few dozen birds to as many as 12,000 each year. Most years, Britain hosts at least a few birds; though, during irruption years, many more can arrive on our shores. Eastern and northern Britain tend to receive the highest number of waxwings during the winter due to their proximity to the North Sea crossing points.

Mountain Ash connoisseurs. Experts believe Rowan (aka Mountain Ash) to be the favoured food of waxings; though they regularly feast on other native and non-native Sorbus berries in the UK. Among these: hawthorn, cotoneaster and dog rose. With Spindle and Whitebeam are also taken with gusto. Where berries are in short supply, waxwings can often be drawn to an area with apples, either left as windfall or deliberately placed.

Feeding habits. Fruiting plants are incredibly important for waxwings in the winter as they typically eat 800-1000 berries a day, roughly twice their body weight. This changes during the breeding season, however, when the species feeds mainly on midges, mosquitoes and other small insects. It is therefore not unusual to see any waxwings remaining in Britain during the spring feasting on insects.

Selfless Symbolism. Spiritualists believe waxwings to be a symbol of selfless generosity. The symbolism of the waxwing totem is believed to teach selflessness and the practice of giving to others for their benefit, and not your own. Waxwings are traditionally associated with the politeness you should have when you give away to others the thing you have craved for or cherished for so long.

Selfish, not selfless. It is believed that the association of waxwings with selflessness and giving stems from their courtship habits. When a male waxwing sets out in search of a mate, it often carries a berry – passed to a female bird in an effort to impress her. The female waxwing then takes the berry and returns it to the male, with the gifting ritual repeated many times until, eventually, mating takes place. While some may view this as a sign of selflessness, in reality, the male instigates this ritual in order to spread his own genes; thus the process, while touching, is actually rather selfish.

Waxwing separation. Two species of waxwing have occurred in Britain: the commoner Bohemian Waxwing (Bombycilla garrulus) and much scarcer Cedar Waxwing (Bombycilla cedrorum). The separation between the two can often be difficult; though the colour of the bird provides a good indicator. A Bohemian Waxwing has a grey chest and belly while a Cedar Waxwing has a brown chest with a yellow belly. Additionally, if the bird’s undertail is a brownish-orange, it’s a Bohemian Waxwing. If the undertail is white, it’s a Cedar Waxwing.

Cedar Waxwing (Bombycilla cedrorum)

A rare repeat performance. Having visited our shores during winter, individual waxwings seldom return to Britain – demonstrated by the incredibly low number of successful ringing recoveries. That said, in 2010, one particular bird bucked this trend, returning to the village of Kintore, in Aberdeenshire, almost a year to the day it had first been ringed by the Grampian Ringing Group. This represented only the third confirmed record of a waxwing returning to the UK in a subsequent winter from over 4,500 ringed birds successfully banded.

Global Abundance. While we Brits tend to think of waxwings as a seasonal scarcity, they are actually rather abundant. The global population of waxwings has been estimated at more than three million birds, and the breeding range covers about 12.8 million km2. Although this species’ population, as of 2013, appears to be declining, the decrease is not rapid nor large enough to trigger a change to their vulnerability criteria. The waxwing is classified by the International Union for Conservation of Nature as being of ‘least concern’.

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Top 10 Facts: Fly Agaric

Infamous. Amantia muscaria is one of the most recognisable fungi in the world. A recent study by European scientists, during which subjects were shown images of various mushrooms, found that respondents successfully identified the species on 96% of occasions. Common, white forms of fungi were successfully identified by only 53% of participants.

Romanticised. The red and white spotted toadstool is rife in popular culture. So much so that garden ornaments and children’s books often depict gnomes and fairies [even Smurfs] using Fly Agaric as a home or seat. The mushroom features strongly in the video game series Super Mario Bros – specifically used as a power-up item – and, perhaps more famously, featured in the dancing mushroom sequence in the 1940 Disney flick, Fantasia. Perhaps this explains its global recognition.

Fly Agaric, spotted at Gosforth Nature Reserve

Toxicity. Fly Agaric contains several biologically active agents. One of these, Ibotenic Acid, is a known neurotoxin; while another, muscimol, is a powerful psychoactive. When ingested, the former serves to intensify the effect of the latter. A fatal dose of agaric has been calculated as 15 caps but, despite dramatisation in historical texts, fatal poisonings are extremely rare. The North American Mycological Association has stated that there were: no reliably documented cases of death from these mushrooms in the past 100 years.

Nasty side-effects. It is not recommended that you consume Fly Agaric, and side-effects of consumption are known to include nausea, drowsiness, muscle spasms, low blood pressure, hallucinations and loss of balance. In extreme cases, seizures and coma have been recorded. Symptoms typically appear between 30-90 minutes after consumption and peak within three hours, although many unlucky souls have reported ‘piercing headaches’ for many days after.

Those Siberians. Amanita muscaria was widely used as an entheogen [psychoactive] by many indigenous peoples in Siberia. In Western parts, its use was mainly restricted to shamans who used the fungi as a means of inducing a trance-like state; while its use in Eastern parts was traditionally more recreational. Here, shamans would take the mushrooms and others would drink their urine: with internal processes serving both to amplify the potency of the mushroom as a psychoactive, and to reduce its harmful toxicity.

‘Fly’ Agaric. The name Fly Agaric stems from the use of this fungi as an insecticide in some parts of Europe, including England and Germany. Often its cap was broken up and sprinkled into milk so to form an irresistible, yet deadly, trap for flying insects. The species’ use as an insecticide was first recorded by Albertus Magnus in his work De vegetabilibus around 1256. Recent research has shown this particular old wives tale to be true, and the famed fly-killer is now known to be Ibotenic Acid.

Berserker myths. Many texts, television shows and even blog posts buy into the historical depiction of Vikings as routine Amanita muscaria users. Specifically, Viking Berserkers were rumoured to consume the fungi prior to battle – to induce a state of unrivalled ferocity. A notion first suggested by Swedish professor Samuel Ödmann in 1784.  There are, however, no contemporary sources that mention this use or anything similar in their description of berserkers. It may just be made up…

Symbiosis. This fungus has a symbiotic association with birch and pine trees – meaning that both the host tree and the fungi derive benefits from a close association. In this instance, the fungal mycelium ferries nutrients into the tree roots and, in return, receives important sugars from the tree’s photosynthesis of sunlight.

Chameleon. The characteristic red colour of Fly Agaric may fade after rain or in older mushrooms – lending the toadstool a washed-out, orange appearance. The famous white spots on the cap, visible after emergence from the ground, are also easily displaced. These are remnants of the universal veil, a membrane that encloses the entire mushroom when it is still very young.

Varieties. Contrary to popular depictions, two additional forms of Fly Agaric are known to occur in Britain. These are Amanita muscaria var. aureola, boasting a vibrant orange-yellow cap, and Muscaria var. Formosa is a rather rare brown or yellow-brown form sporting a slightly tinted veil. Both of these are seldom seen and those lucky enough to stumble across them on their fungal forays should count themselves lucky.

Top 10 Facts: House Sparrow

A history of declines. Once one of Britain’s commonest birds, sparrow numbers have crashed in recent years, with London alone losing three-quarters of its sparrows between 1994 and 2000. Declines in rural sparrow populations are thought to be a result of changing farming practices, particularly the loss of Winter stubble, though the exact reasons for the species collapse in urban areas are poorly understood and still, to this day, the subject of research.

Sparrow clubs. Throughout history, house sparrows were commonly viewed as a pest species in Britain. So much so that dedicated “sparrow clubs” were formed with the sole intent of dispatching as many birds as possible. From the mid-18th century, most parishes had sparrow clubs and bounties were paid for dead sparrows until the late 19th century when it was accepted that the control measures did not work. The reasons for these control measures centre on the perceived status of sparrows as a major pest of cereal crops.
Invasive Species. House sparrows have been successfully introduced to numerous countries around the world, including both North and South America, East and South Africa, Australia and New Zealand. The first of these introductions took place in the USA where, in 1852, sparrows brought across from England were released in New York with the intention of controlling the number of damaging Linden moths. The sparrows had other ideas and quickly spread across the continent…

Infidelity. DNA research has shown that 15% of house sparrow offspring are the result of either the cock or hen birds mating with another partner, confirming the sparrow’s reputation for sexual infidelity. A study in 2016, however, hinted that cuckolded male sparrows stopped tending to their chicks – greatly reducing the chances of their rivals young successfully fledging.

Nest theft. Sparrows frequently take over the nests of house martins and swallows and, in a rather grim turn of events, often eject eggs or young birds already present in the nest. With the less dominant hirundines unable to stop them. In many parts of Europe, sparrows also nest in colonies in the base of white storks’ nests. This is thought to be because such nests are well-insulated and safe from predators.

Ringing recoveries. Though rightfully thought of as sedentary, British-ringed house sparrows have been recovered as far away as France and Belgium – showing that, despite reputation, the species does indeed move considerable distances. Anecdotal evidence also suggests that some of the birds seen in Britain may migrate from Scandinavia; although, by large, most sparrows do not move far from their place of birth.

Latin name. The house sparrows latin or ‘scientific’ name and its usual English name have a similar meaning: the Latin word passer, like the English word sparrow, is a term for small active birds, derived from a root word referring to speed. The Latin word domesticus means “belonging to the house”, and, like the species common name, is a reference to its close association with humans.

House Sparrows are capable of swimming underwater! Yes, its true. Even though these birds are not water birds, it has been observed that they can actually swim underwater to move from one place to the other. Apparently, this behaviour was first observed when a sparrow was caught in a trap positioned atop a water dish. The bird, obviously opposed to captivity, proceeding to dive into the water and swim from one part of the trap to another seeking escape. Which sadist would want to trap a sparrow and test this theory, however, is a little beyond me… 

Visual dominance.  Older male sparrows with large black patches on the body are thought to be dominant over males with small patches. The size of the black breast bib – the badge – and the bill colour of male birds change over the course of the year and is thought to relate to the individual’s testosterone levels. Due to the biological cost of producing the pigment necessary to alter their appearance, it is thought that only birds in peak physical condition can afford this – signalling their status as a suitable mate for any passing females.

Top 10 Facts: Long-eared Owl

Communal Roosts. A unique characteristic of the Long-eared Owl is its tendency to roost communally during Winter. Usually solitary, this species has been known to gather in groups of between 2 to 20 individuals, usually in thick cover, but in some locations have been observed gathering in incredibly large numbers. A prime example of one such prominent roost site is the town of Kikinda in Serbia where some observers claim to have counted upwards of 1000 owls in and around the town during colder months.

Lazy nesting. Unusual among owls, the Long-eared Owl nests on a platform as opposed to within cavities. Usually positioned high in the upper branches of conifers. While perfectly capable of constructing their own nests, this species readily utilises those abandoned by other bird species and, in the UK, often opts for disused crow or Magpie nests. Less commonly, birds have also been observed occupying the former nests of a suite of species ranging from Woodpigeons and Sparrowhawks to Grey Herons, and on more than one occasion have been found to occupy disused squirrel dreys.

Global reach. The Long-eared Owl has one of the largest breeding ranges of any owl species, occurring across the Northern Hemisphere from Japan in the East, through China, parts of Pakistan and Mongolia, into Russia, throughout Europe and across large parts of the USA. The species also breeds in smaller numbers in Northern Africa; whereas its Winter range extends to encompass parts of India, Mexico and the Middle-East.

Subspecies. There are presently four separate subspecies of Long-eared Owl recognised around the globe. These are the nominate A. otus, found throughout Europe, North Africa and into parts of East Asia; A. o. canariensis, found on the Canary Islands; A. o. tuftsi, found throughout Western parts of the USA, Canada and Mexico and A. o. wilsonianus found throughout Eastern parts of North America.

Folklore. In Ancient Greece, the Long-Eared Owl was considered rather unintelligent with the term “otus” used frequently to describe simpletons.

The Irish Owl. Long-eared Owls are thought to be the commonest owl in Ireland, with a scattered range throughout the whole country. Contrary to population trends in the UK which show the species to have declined substantially over recent years, the Irish owl population has increased its range by 12% in the Southwest of the country. Possibly as a result of an increase in coniferous woodland (or improved surveying methods).

Long-distance migrant. Like their cousin, the Short-eared Owl, the Long-eared Owls resident in Britain are bolstered by arrivals from the continent during Winter. Typically from Scandinavia, Eastern Europe and Russia. The BTO report that one bird, ringed in Cumbria, was found 8 months later in the Mariy region in western Russia, 3,279km from its ringing site. Whereas most of the ringed birds recorded in the UK appear to arrive from Germany. It is not uncommon to see Long-eared Owls arriving over the sea during Autumn, and they regularly seek respite on Oil-rigs and ships during the perilous North Sea crossing.

Sour relations. Perhaps more so than any other European owl species, the Long-eared Owl often falls prey to other avian predators, including other owl species. Eagle Owls and Goshawks have been shown to regularly predate this species, while Tawny Owls are known to kill the former in an effort to claim dominance over a territory and thus, a food supply. Studies have shown a suite of diurnal raptors, ranging from Sparrowhawks and Peregrines to Red Kites to actively hunt Long-eared Owls and it is safe to say that the species does not have it easy when it comes to competition with rivals. On the reverse, some studies have recorded instances of Long-eared Owls predating Little Owls.

In trouble. Following a boom in the 19th Century, the British Long-eared Owl population declined substantially during the 20th Century. Anecdotal evidence has linked this to the resurgence of the Tawny Owl population following its suppression via persecution in earlier years and it is thought that the recovery of the larger owl may be an attributing factor. The fact that Long-eared Owls are flourishing in Ireland, from which Tawny Owls are absent, lends credence to this theory. It is accepted that Long-eared Owls can coexist with Tawnies when enough natural food is present; thus the decline of this species across Britain likely relates to a change in habitat and a corresponding decline in prey species. It is thought that only 1000 pairs of Long-eared Owl now remain in the UK.

Doting dads and diet description. During the owls breeding cycle, it is the male that does most of the hunting – depositing prey at the nest before egg-laying begins, providing the female with sustenance during incubation and providing the bulk of the prey for the fledgeling birds. Of the various prey items regularly taken by this species, voles, mice, rats and shrews are the most common, making up over 90% of the diet; though the species readily predate small birds when an opportunity presents itself. Bird species taken by Long-eared Owls include Wheatear, Meadow Pipit, Chaffinch, Reed Bunting and House Sparrow; although instances of predation on Pheasant poults have been recorded.

 

 

 

 

 

 

Top 10 Facts: Willow Tit

Late discovery. The Willow Tit and the much more abundant Marsh tit are incredibly difficult to tell apart, even by professional birders. They are so similar, in fact, that they were once mistakenly believed to be a single species. Indeed, the Willow Tit was the last regular British breeding bird to be identified – only named in 1897. This split was largely due to observed differences in the calls of both species: Marsh Tits uttering a sneeze-like pitchou call, and Willow Tits a harsher zee-zurzur-zur.

Spot the difference. As time progressed, a number of ways to tell apart Marsh and Willow Tits were identified. For example, the cap of the former appears glossy compared to the duller tones of the willow, whose cap also extends further on to the nape. Similarly, the Marsh tits possess a larger bib; while the white cheeks of the Willow are often larger and more conspicuous than that of the Marsh. Additionally, Willow Tits also show a pale wing panel caused by the pale edging of the bird’s secondary wing feathers.

Habitat preference. Despite their name, marsh tits are known to prefer drier habits and are often found in expansive areas of broadleaf woodland – especially those boasting a prominent shrub-layer. Willow Tits, on the other hand, are associated with wetter areas, including wet-woodland. They are more likely to be seen in conifer forests also and are the species most likely encountered on disused industrial sites and wasteland areas boasting a healthy shrub layer. The Willow tit is absent from Ireland and much of Scotland but is known to occur further North than it’s close cousin.

Yet more confusion. In the past, the Willow Tit was considered to be conspecific with the Black-capped Chickadee of North America – another ascetically similar species. Confusion between the two species can be observed in the Peterson Field Guide to Birds of Britain and Europe. Here, the American species is listed as an alternate name for Willow Tit while, in reality, both species (alongside the Marsh tit and Carolina Chickadee) are only similar in appearance.

Conservation priority. Myriad reasons have meant that the British Willow Tit population has declined by 94% since 1970, with the species now completely absent from former haunts in the South-East and elsewhere in Britain. Populations in the North of England have suffered declines also but are clinging on due to the natural regeneration of wet scrub on old industrial land. Currently, the UK’s Willow Tit population is estimated at 3400 pairs, making this species on of the most pressing conservation issues in the UK today.

Susceptible to eviction. Evidence suggests that competition from Blue and Great Tits could be a major factor contributing to the decline of the Willow Tit in the UK. Willow Tits nest in cavities excavated from dead wood, with the nest building process often proving to be a very noisy affair. This, coupled with the obvious visual implications and the production of visible byproducts such as wood chips, means that excavating Willow Tits are vulnerable to detection from both the species previously mentioned. Both of which can extirpate the occupants of a nest with relative ease.

Are woodpeckers to blame? Once a nest hole has been excavated and lined, Willow Tits can still be noisy around their breeding site, leaving them vulnerable to detection by Great Spotted Woodpeckers, which are accomplished at extracting prey from rotten wood. Willow Tits are single-brooded and if predation occurs at the chick stage, the pair is extremely unlikely to breed again that year.  Numbers of Great Spotted Woodpeckers have increased dramatically in the UK (by 314% between 1970 and 2006), and
Willow Tits may have suffered a corresponding increase in predation rate.

Habitat loss. Despite a steep population decline, Willow Tits can still occur at relatively high densities in some brownfield sites where wet-scrub habitat is plentiful. Such disused industrial sites have, however, become less common in recent decades due to development, agriculture and natural regeneration. It is assumed that habitat loss is the primary driver of Willow Tit declines across Britain. Over-browsing by deer, which limits the regrowth of the species preferred wet-scrub, is almost certainly worsening the problem at many sites.

Novelty woodpecker. Willow Tits are the only British tit species to excavate a new nest hole each breeding season, with much of the work usually carried out by the female bird. Nests are positioned usually around a metre above the ground in a rotten stump and are established by the hen bird through boring and chiselling at the wood – prying off small chippings until the hole is widened sufficiently to enable breeding. Such nests are often lined with soft materials such as fur, moss or narrow strips of bark fibre. The particular nature of Willow Tit nests means that they seldom inhabit nest-boxes; though some people have successfully attracted the species by lining boxes with sawdust.

Claim to fame. The Willow Tit was featured in Gilbert and Sullivan’s 1885 operetta, The Mikado, in the song Willow Tit Willow. Sam the Eagle and Rowlf the Dog performed this in the first season of The Muppet Show.

 

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Top 10 Facts: Yew

Historic significance. One of the oldest wooden artefacts ever discovered by modern humans was made from Yew – a spearhead found in Essex dated at approximately 450,000 years of age. This particular spearhead was unearthed in 1911 at Clacton-on-sea and represents not only the oldest wooden find from the UK but one of the most significant worldwide.

Warfare. Yew wood is extremely hard-wearing and , as a result, was used frequently during the Middle Ages to make the renowned English Longbow – a weapon that helped the English win many historic battles. Particularly those during the Hundred-Year War. The traditional construction of a longbow consists of drying the yew wood for 1 to 2 years, then slowly working the wood into shape, with the entire process taking up to four years. The demand for yew wood in England was, at one point, so great that it depleted stocks across a huge area of the UK, resulting in the subsequent importation of Yew from the continent.

Toxicity. All parts of the Yew, with the exception of its bright red fruit, are known to be toxic, and over the centuries, there have been numerous fatalities as a result of Yew poisoning. Among these, the 2014 incident involving the unfortunate death of Ben Hines. Yew was also used by the Celtic Chieftain Catuvolcus (53 BCE) as a means of suicide so to avoid becoming a roman slave. In a similar way, the historian Orosius notes that when the Astures were besieged at Mons Medullius, they preferred to die by their own swords or by the yew poison rather than surrender. By all accounts, a death by yew poisoning is a rather grizzly one.

Cancer treatment. Despite its toxic reputation,  a chemical found in yew – taxol – has been found to have anti-cancer effects. These chemicals have since been synthesised and are now being used in the treatment of breast, ovarian and lung cancers.

Ties with Christianity. The Druids regarded yew as sacred and planted it close to their temples. As early Christians often built their churches on these consecrated sites, the association of yew trees with churchyards was perpetuated, suggesting that the renowned ties between the yew and Christian holy places is, in fact, a myth. With trees simply being left to their own devices and seldom disturbed due to the human significance of said sites. It is also suggested that early Christian’s continued the tradition of planting yews on holy land so to placate those whose religion had been replaced by Christianity.

A long history of death. The yew has been viewed as symbolic of death, sorrow and sadness since Egyptian times. They used its foliage as a symbol of mourning and, as such, the myths surrounding the tree were passed into both Greek and Roman cultures. With the Romans using the wood of the yew to fuel funeral pyres. It is thought that much of the funereal significance of the Yew in Britain came from the influence of the Romans, as well as the aforementioned pagans.

Key to Immortality. Yews can live for upwards of 3000 years. This is due to a number of ingenious techniques that the tree uses to ensure its longevity. Among these, the new shoots put out at the base of the trunk which form buttresses, of sorts, stabilising the main trunk and protecting it from harm. When the main trunk of the yew eventually dies, these shoots may rise to form a new tree. Yew’s are also frequently found to possess internal roots, put down by branches into the decaying heart of the tree; thus allowing for the formation of new trees even when the main body of the original yew has perished. Additionally, when yew branches reach the ground they can become embedded, taking root and leading to the growth of a separate tree connected underground to the old one. Some of the world’s oldest yews have survived in this way – continuing as fragmented trees, even when the original plant has died.

Yew berries spotted on a walk near Bedlington

Fungi. Only one fungus is regularly found on the yew, the yellow polyporus sulphureus, otherwise known by its common name of Chicken of the Woods.

Cultivars. Yew is a popular choice with horticulturists due to its landscaping and ornamental value and well over 200 cultivars have been named. The most popular of these being the Irish yew (T. baccata ‘Fastigiata‘), a cultivar of the European yew selected from two trees found growing in Ireland. There are also several forms with yellow leaves, collectively known as golden yews. In some locations, e.g. when hemmed in by buildings or other trees, an Irish yew can reach 20 feet in height without exceeding 2 feet in diameter at its thickest point, although with age many Irish yews assume a fat cigar shape rather than being truly columnar. (source)

Record-breaker. The Fortingall Yew, found in the churchyard of the village of Fortingall in Perthshire, Scotland, is thought to be one of, if not the oldest tree in Britain – estimated at between 2000 and 3000 years of age. The tree once held the record for the largest girth of any British tree (16 meters) but has since succumbed to natural decay, splitting into several separate stems via the methods mentioned previously. As a bonus fact, it is also suggested that Pontius Pilate was born in its shade and played there as a child.

Top 10 Facts: Surprising UK Non-Natives

American Bullfrog Lithobates catesbeianus. Around twice the length of our native Common Frog, American Bullfrogs are most often identified by their loud, deep calls. Deemed a risk to British wildlife due to their tendency to prey on everything from small mammals and ducklings to other amphibians, Bullfrogs may also spread Batrachochytrium dendrobatidis – a form of Chytrid fungus – to native amphibians. Due to their negative impact on the native ecosystems, bullfrogs have been subject to an eradication scheme, costing up to £100,000 to date. Despite conservationist’s best efforts, this species remains present in a select few areas across England. Did you know that bullfrog tadpoles can grow up to 15cm?

Topmouth Gudgeon Pseudorasbora parva. Widespread but scattered across England, Topmouth Gudgeon inhabit well-vegetated ponds, channels and lakes. This nondescript fish species compete with native fish and farmed stock for food, and has been found to severely deplete or even eradicate native fish and invertebrate populations in areas of particularly high density – gudgeon have been recorded at densities of up to 60 fish per square meter – and has been directly linked to the eutrophication of British waterbodies due to it’s feeding tendencies which limit zooplankton abundance. Thus, in turn, increasing phytoplankton prevalence.

Coati Nasua nasua. A close relative of the North American Raccoon, up to ten animals were known to be living wild in South Cumbria until at least 2008. Given the small-scale of the reported population there are no known environmental impacts at present; though it is thought that, should this population expand or future escapes occur, that the Coati could become a significant predator of native wildlife. South Lakes Wild Animal Park was initially implicated in the spread of Coati’s in Cumbria, although the spread of sightings – ranging from Kendal and Kentmere to Langdale and Penrith – suggest other possible escapes.

American Skunk-cabbage Lysichiton americanus. A rather conspicuous plant boasting yellow flowers aesthetically similar to native Lords and Ladies, the stronghold of Skunk-cabbage appears to be Southeast England, most notably Hampshire. Although populations now exist at various intervals between Cornwall and Inverness. Like many invasive botanicals, this species is thought to decrease floral diversity within occupied areas and it is thought – based on Germans studies – that it can have a significant impact upon marshland plant communities. The economic impact of American Skunk-cabbage remains unknown; though with the species seemingly consolidating its hold in the UK, it is likely that further study will be needed to properly assess its impact.

American Skunk-cabbage

Quagga Mussel Dreissena bugensis. In October 2014 Quagga Mussel was found in Wraysbury Reservoir and the Wraysbury River, near Egham, Surrey –  the first UK record of this decorative yet damaging species. Originally from the Ponto-Caspian region, the mussel can significantly alter whole ecosystems by filtering out large quantities of nutrients and is also a thought to pose a serious biofouling risk by blocking pipes and smothering boat hulls. It is thought that there are no effective eradication techniques for Quagga Mussel once it becomes established, thus all records of this species should be reported immediately.

Carolina Wood Duck Aix sponsa. The wood duck is the only congener of mandarin duck and females and young birds are hard to distinguish from that species – meaning that this species may go unrecorded in many instances. First reported in the wild during the 1830’s Wood Ducks have been recorded breeding at many locations across the UK including in Wiltshire, Berkshire, Devon and Kent. Despite this, the species has not yet formed a self-sustaining population anywhere in the UK. While there is potential for Wood Ducks to compete for nest-sites with other hole-nesting bird species, this is one non-native species that does not appear to have an overwhelmingly negative impact on the British ecosystem. With escapes from captivity still relatively common, it is likely that individuals will continue to be found wild long into the future.

Carolina Wood Duck

Pitcher Plant. There are currently twelve known populations of this carnivorous plant species known from the UK, with the largest being found on Wedholme Flow where there are ongoing efforts to control numbers. The species has been eradicated from a further ten sites across the UK; where the vector for introduction was thought to be transplanting from private collections. Large Pitcher Plant populations have been shown to restrict the growth of native botanicals and, based on studies in Ireland, it is thought that the species may impact upon peat regeneration due to its tendency to restrict the growth of Sphagnum Moss. There are no known economic effects of this species, with the cost of removal covered, to date, by conservation bodies in charge of the reserves on which it grows.

Wels Catfish Silurus glanis. Growing up to 3m in length across its native range in Europe and Asia, this catfish is a voracious predator of birds, mammals, amphibians and invertebrates and. as such, there is concern that the presence of this species within UK waters may have an adverse effect on biodiversity. Indeed, studies from Spain suggest that the Wels may have a detrimental impact on waterbird populations. Widespread but scarce in the UK, the majority of Wels sightings come from Southern England where, despite expert advise, it is continuously stocked for sporting purposes. The first official record of this species living wild in the UK was at Morton Hall, Norfolk during 1864.

Wels Catfish

Tree-Of-Heaven Ailanthus altissima. With elongated, pinnate leaves, this species appears not dissimilar to Walnut or Ash and is planted heavily in urban areas. This has led to its escape in Southern England – occurring to such an extent that it has now become invasive in the London area. The impact of Tree-Of-Heaven remains relatively small due to its presence in areas of low conservation value; though it is thought that as temperatures warm, the species will acclimatise more readily to the natural ecosystem. In areas of Southern Europe – where the species has already established – Tree-Of-Heaven has been shown to actively exclude native flora. The plant also poses a slight risk to humans with the mild toxins found within the leaves often causing dermatitis upon contact.

Killer Algae Caulerpa taxifolia. A bright green seaweed with upright leafy fronds, dense growths of this marine plant can significantly alter habitat structure by displacing both floral and faunal species. It is also inedible to most native species, has been shown to smother sea-grass meadows – an important habitat type for many native marine species – and causes myriad problems for humans by reducing fish stocks and impacting upon the performance of fishing gear. Very popular in the marine aquarium trade in the UK, this species is not known to exist in the wild just yet; though based on it’s severe impact upon the Mediterranian ecosystem, it deserves a spot on this list nonetheless. Indeed, conservationists and anglers alike are predicting its spread into the wild in the very near future. Perhaps this addition to the list can be seen as a forewarning of things to come?