GB Birds
GB Mammals
GB Herps
GB Misc Creatures
GB Reintroductions
Euro Birds
Euro Mammals
Euro Herps
Euro Misc Creatures
Trip Reports

Harlequin Ladybird
(Harmonia axyridis) Dorset, 2006

Tube Web Spider
(Segestria florentina) Kew, 2009

Signal Crayfish
(Pacifastacus leniusculus)
Herts, 2010

Yellow Tailed Scorpion
(Euscorpius flavicaudis)
Kent, 2011

Yellow Tailed Scorpion
(Euscorpius flavicaudis)
Kent, 2011

Red Swamp Crayfish
(Procambarus clarkii)
London, 2011

Red Swamp Crayfish
(Procambarus clarkii)
London, 2011

Birding Top 500 Counter


British Isles Exotic and Introduced Miscellaneous Creatures


New Zealand Flatworm - Arthurdendyus triangulatus

First discovered in Northern Ireland in the 1960's it is now present in West Scotland and central England, it is a pest decimating earthworm populations.


Stick Insects

Prickly - Acanthoxyla geisovii from New Zealand.
Smooth -
Clitarchus hookerifrom New Zealand.
Unarmed -
Acanthoxyla inermis from New Zealand.
European -
Bacillus rossius from the Mediterranean
White’s Sicilian Stick-insect -
Bacillus whitei from Sicilly.
Acanthoxyla prasina
from New Zealand.

Another species Clonopsis gallica from New Zealand has been introduced on to Jersey.

The five species, Acanthoxyla prasina, unarmed, prickly, Mediterranean and smooth are found in small colonies in Cornwall. All derived from pets and accidental introductions on imported plants the mild climate has allowed them to persist. A few colonies also exist in other parts of the country.

Tresco Gardens is a hotspot, they are widespread on the Scilly isles and SW Cornwall.


Harlequin Ladybird - Harmonia axyridis

A highly invasive species first recorded in East Anglia in 2004, it has quickly spread and is present in most on England south of Lancashire / Yorkshire and has not yet reached the South West. As its name suggests is comes in 24 differnt colour forms From mostly black to mostly orange to mostly yellow with lots of forms inbetween. Originally introduced to central europe.


Signal Crayfish - Pacifastacus leniusculus

One of five species introduced to the UK, the Signal crayfish is the most distinctive and most disruptive. Originally introduced for food it quickly escaped and has out competed the native species and carrys a fungus which kills the native species. Found on most waterways.

Other species are not as widespread or disruptive

Noble crayfish - Astacus astacus
Turkish crayfish A.leptodactylus
Red swamp crayfish Procambarus clarkii

Found primarily in London, Highgate ponds has a large population.

Spiny-cheek crayfish Orconectes limosus

Yellow Tailed Scorpion - Euscorpius flavicaudis

They arrived by hitching a ride on ships and were found at several docks, the Sheerness colony has been in existant since at least the 1960's.

Chinese Mittern Crab - Eriocheir sinensis

First recorded in the River Thames in the 1930s, possibly arrived in ships ballast water, originally from the far east they have no competitors in the UK so have recently dispersed and numbers have risen and has now spread to many other English rivers hot spots are the Thames, Humber and Tyne and the east coast.

Large Checkered skipper - Heteropterus morpheus

Introduced into Jersey in 1940's but died out in in the 1990's


Tube Web Spider - Segestria florentina

Well established for about 100 years in the south and london. It has a nasty bite but is not venomous but is very aggressive.

False Widow Spider - Steatoda paykulliana

A major colony exists in Plymouth and they are spreading. This species has a nasty and venomous bite and is aggressive.

Skeleton Shrimp - Caprella mutica

A relatively large, shrimp native to north-east Asia. This species is now widespread in Scottish coastal waters, occurring in high numbers on artificial structures such as mooring ropes and nets at fisheries, and on pontoons and boat hulls in marinas.


Pacific Oyster - Crassostrea gigas

Introduced initially in Cornwall, Essex and Wales for food production. It has been widely farmed in England, Scotland, Wales and Northern Ireland. 'Escapees' have established populations in many regions.

Slipper Limpet - Crepidula fornicata

In Britain, it is present on the east coast south of Hull, the length of the south coast and northwards along the west coast to Cardigan.

New Zealand Mud Snail - Potamopyrgus antipodarum

Turkish Snail - Helix lucorum

A colony is present in Hertfordshire

Cliveden Snail - Papillifera papillaris

Accidently imported from Italy on a marble balustrade in 1896 into Cliveden Park, Bucks only discovered in 2008, another population has been found on Brownsea Island in 2010.


Leathery Sea Squirt - Styela clava

A large, leathery stalked sea squirt that has spread extensively since its first European occurrence in Plymouth in the early 1950s, and now occurs in natural habitats as well as docks, harbours and marinas. It is extensively encrusted by other species.


Rainbow Trout - Salmo gairdneri

A game fish released from the late 1800's and still commonly released it is common in rivers and lakes throughout the UK.

American Brook Charr - Salvelinus fontinalis

An American fish found mainly in the NW, Wales and Scotland. A late 1800s introduction for game fishing.

Common Carp - Cyprinus carpio

Commonly introduced to lakes in the south, conditions further north are unsuitable for breeding and they have not done well there.

Goldfish - Carassius auratus

Commonly kept in captivity and have been widely released.

Bitterling - Rhodeus amarus

Escaped from captivity in the north of England where it is scarce but self sustaining.

Orfe - Leuciscus idus

Commonly kept in captivity and have been widely released.

Wells - Silurus glanis

A large catfish first introduced into Woburn abbey in the late 1800's but has spread into lots of lakes and river systems in the south. It is originally from mainland europe.

Guppy - Poecilia reticulata

A tropical species that has become established in several areas where the water is warmed by factories and power stations. Other commonly kept tropical species can also be found at these sites but are much less common.

Zander - Stizostedion lucioperca

Introduced by anglers to rivers and lakes in Southern England but is rapidly spreading. It is a vicious preadator and harmfull to small native species.

Topmouth Gudgen - Pseudorasbora parva

Similar to the Gudgeon but with the mouth pointing upwards, it breeds prolifically and carries a parasite potentially dangerous to native species.

Pumpkinseed - Lepomis gibbosus

A North American native, present in the South East and East Anglia, it is not spreading and its introduction method has not been confirmed.

Sunbleak - Leucaspius delineatus

A recent introduction in the 1980's it is currently restricted to Southern England but is spreading.

Prickly Stick Insect
(Acanthoxyla geisovii) Cornwall, 2006

Unarmed Stick Insect
(Acanthoxyla inermis) Cornwall, 2007

Smooth Stick Insect
(Clitarchus hookeri)
Cornwall, 2007

False Widow Spider
(Steatoda nobilis)
Cornwall, 2009

Cliveden Snail
(Papillifera papillari)
Bucks, 2009

Signal Crayfish
(Pacifastacus leniusculus)
Herts, 2010

Unarmed Stick Insect
(Acanthoxyla inermis)
Cornwall, 2010

Acanthoxyla prasina
Cornwall, 2011

Eriocheir sinensis
Cambs, 2013

White’s Sicilian Stick-insect
Berks, 2014

Turkish Snail
Herts, 2014
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