Category Archives: Invasive species in Britain

Beetles in the Bonsai

Watch out for this beetle.  If discovered, it should be immediately reported to Plant Health and Seeds Inspectorate at 01904 465625 or

The Citrus Longhorn is an Asian beetle, accidentally imported with ornamental trees from Korea, China and Japan, and discovered at a Rutland school last week.  Like all UK sightings so far, it was found in a Japanese maple, but without a natural predator it poses a serious threat to a wide range of native shrubs and trees. Continue reading Beetles in the Bonsai

Grey squirrel pie fad

Gamekeeper Paul Parker with some dead Grey Squirrels

Grey squirrel pie continues to gain in popularity across the country. I enjoyed this comment in the Manchester Evening News, explaining the origin of the debate on what squirrel actually tastes like.

“Country squirrels live on a diet of sweet things like berries, unlike their urban cousins who will eat mostly anything found thrown on the streets. This diet can make their meat taste sweet, and if cooked right can have a taste between duck and lamb (without the greasy fat usually produced by both cooked animals). The squirrel I ate had a sweetish taste although not much meat for a feast! “

Image from Pest controller moves south to feed demand for squirrel pie

Alien crabs on the menu

The idea of harvesting the invasive Chinese Mitten Crab, currently clogging up the Thames and rapidly spreading through Britain, is taking shape, with a conference planned for March to discuss the pros and cons.

It’s been proposed to use fyke nets, as pictured above.  But these long net tubes held open by hoops are also a very efficient means of trapping eels, now a threatened species in Europe.  Another drawback is, if the crab fishery were an economic success, people might be tempted to introduce the Mitten Crab to new rivers. As Paul Clark, marine biologist at the Natural History Museum and conference organiser, puts it:

“We are damned if we do and damned if we don’t. Mitten crabs have few natural enemies capable of reducing their numbers, but the establishment of a fishery would certainly carry risks.”

In Shanghai the Mitten Crab (Eriocheir sinensis) is a delicacy.  They are eaten steamed, as this best preserves the flavour and keeps the meat tender.

See the Independent and previous post

Grey squirrels don’t threaten birds

Grey squirrel

A new study has found, contrary to popular belief, that grey squirrels do not have a significant impact on the populations of many of England’s woodland bird species. Although there was some evidence that grey squirrels may locally suppress the populations of some speciest through their preying on bird eggs, they do not appear to cause the birds any widespread or lasting harm. BBC

Eagle owls and boars, not wanted in the UK

Controversially, DEFRA have blacklisted eagle owls and boars as non-native species, leaving them unprotected and classed as unwelcome invaders.  Arguments have been put forward for both species to be accepted: boars were part of the Britain’s fauna until their extinction in the middle ages, and there are suggestions that Eagle owls also lived here in the past, although this involves going much further back in time, when Britain was still part of the European land mass.

Four new bird species added to pest list

The government body Natural England have added four non-native species to the list of birds that can be shot without having to apply for an individual license: Ring-tailed parakeet, Monk parakeet, Canada goose and Egyptian goose.

The Ring-tailed parakeet, a conspicuous resident in the south of London, is often a scourge for farmers in its native terrain (ranging from Africa to the Himalayas), as large flocks wreak mass destruction on crops.  So far only a few isolated incidents of crop-damage have been reported in England, so its inclusion in the list would seem to be a precautionary move. There is also concern about the impact of this rapidly expanding species on native wildlife, particularly other tree hole-nesting birds, such as woodpeckers.

Any species on the general license list can only be culled with legitimate justification.

More in Independent and RSPB

How to catch and cook signal crayfish

George Monbiot has put together this step-by-step guide with photos about how to catch and cook the dreaded red-clawed signal crayfish (Pacifastacus leniusculus), a large, aggressive American species that has wiped out almost 95% of the native white-clawed species (Austropotamobius pallipes) since it was introduced to the country in the late 1970s. Read in the Guardian

Piranha found in English river

According to the Environment Agency, a dead piranha has been found in the River Torridge in Devon.  Nothing to panic about though. The EA said that the piranha had probably been placed in the river once the fish became too large for its tank and died because it could not tolerate the low temperatures. The Daily Telegraph

Skunks breeding in England

Experts believe that skunks could now be living and breeding in the English countryside. Specifically there are reports of skunks rummaging through rubbish and allotments near Coleford. The animals may have been released into the wild after being kept as pets when new legislation banned removing their scent gland in 2007 – dozens may have been released by owners afraid of being sprayed by their foul smell.  The Daily Telegraph

The story has come to light after a three-month-old female skunk, going by the name of Ozzy (above pic) was captured in the Forest of Dean in Gloucestershire, and handed in to the Vale Wildlife Hospital in nearby Tewkesbury. Story in the Daily Express

Australian swans threaten native swans

Australian black swans are spreading across Britain and threatening native white and mute swans. The birds have escaped from private collections and are now breeding at dozens of sites across the country. They are more aggressive, and they may “out compete” native swans for food and habitat in many areas. There may also be a problem of interbreeding. A BTO project found 500 reports of black swans, in at least 170 different locations around the UK.  The black swan is currently not on the British List of birds, compiled by the BTO because the population was not considered to be self-sustaining at the last review. This may now change in the light of the new information. The black swan occurs naturally in western, eastern and southeastern Australia, Tasmania, and southern New Guinea. The Indepedent

Jumping lice to fight knotfeed?

In a plan to use one non-native species to combat another, DEFRA is considering releasing jumping lice to fight battle against Japanese knotweed. The non-native sap-sucking insect would be released under licence to tackle the weed, which causes serious damage to buildings, roads and railway lines; while driving out other plants; and eroding river banks. Knotweed was originally introduced as an ornamental plant the early 19th century. It now lives unfettered without predators in the countryside. The Indepedent

Japanese knotweed is often considered Britain’s most invasive plant species.DEFRA notes: “The species also causes problems in terms of flood management. It increases the risk of riverbank erosion when the dense growth of the plant dies back in the autumn exposing bare soil. It can also create a flooding hazard if the dead stems are washed into the streams and clog up the channel. A fragment of root as small as 0.8 grams can grow to form a new plant.”

Plan to save British crayfish

A £210,000 breeding programme has been started to save Britain’s rare native white-clawed crayfish. The species (Austropotamobius pallipes) is in danger of being wiped out by invasive American signal crayfish, which carry a disease, crayfish plague, which is fatal to the British species. The crayfish are being bred at secret locations in the south-west of England. American crayfish were introduced in the UK twenty years ago for farming. This has since led to the disappearance of almost 95% of the native species, which faces extinction from UK waters within 30 years unless new populations can be created in safe, uncontaminated waters. The Guardian