Sometimes Cute (but very often extremely) Deadly. A guide to some of Britain's invasive wildlife.

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DEADLY An illustrated guide to some of Britain’s invasive species.



DEADLY An illustrated guide to some of Britain’s invasive species. Printed on recycled paper by the lovely folks over at The Inkwell Print, Coventry.

INTRODUCTION: Britain is thought to have over 3000 species classed as ‘non-native’ that have arrived here throughout history. The majority of which pose little to no threat to our wildlife, such as the little owl, pheasant and the rainbow trout, as well as whole host of plants such as the horsechestnut. However, some species are responsible for accelerating the decline and damage to some of our native wildlife and their habitats. Dubbed ‘invasive species’, through carrying deadly diseases, outcompeting native species for food or drastically altering ecosystems, they are one of the most substantial threats to biodiversity alongside climate change. Islands such as the UK are particularly at risk because their wildlife evolves separately from the mainland, with the flora and fauna having learned to deal with very specific habitats and predators. As a result, around 60% of all extinctions take place on islands. The use of importing animals for food, fur and sport as well as the rise in global transport is often the reason behind non-native species having arrived in recent history. With 37% of all invasive species recorded in the last 200 years arriving between 1970-2014. Thoroughly unsuited to our ecosystems, they are inadvertently causing damage to species already struggling with the effects of climate change and habitat loss. The eradication and management of invasive species is often a complex topic. This guide aims to introduce you to a few ‘alien species’ in an informal (and often very silly) way. I hope you enjoy this illustrated guide and get to know more about the fascinating wildlife that call this island home, as well as what we can do to protect them.


GREY SQIRREL The one invasive species you probably know about, grey squirrels were brought over from America in the late 1800s by some well-meaning Victorians. Quickly, the grey squirrel was introduced to various different parks and estates across the country. The species has since been linked to the rapid decline of the native red squirrel and the significant damage of some of our woodlands. Grey squirrels are carriers of squirrelpox which they themselves are immune to but is unfortunately fatal for the red squirrel. Grey squirrels’ larger numbers also mean they can out-compete the red for food, with 2.7 million grey squirrels compared to 287,000 red, according to The Woodland Trust. As a result, the remaining small populations of red squirrels can only be found where grey populations are not well-established (which isn’t very many places.) However, due to culling, industrialisation and the clearing of forests in earlier centuries, the red squirrel population was already in decline but heavily exacerbated by the arrival of the grey. Grey squirrels are considered a nuisance through stripping bark and nibbling at young saplings, which can have devastating impacts on our woodland. Stripping bark leaves trees susceptible to fungus and rot, which is very bad news for the timber trade and woodland conservation. The economic impact as a result of this damage is often estimated to be millions each year.

Scientific name: Sciurus carolinensis British name: Tree Rat Not to be confused with: Red squirrel. Grey squirrels are larger and well, grey.

The government has recently backed plans to give grey squirrels a form of oral birth control as a more targeted and humane way of monitoring populations. There is also talk of genetically altering fertility genes in grey squirrels to slow population growth, but this is still in its research phase. It’s undeniable grey squirrels are very popular with British park-goers (unless you have a bird-feeder in your garden, in which case you may feel differently) and many of us are downright delighted when we can get one to feed out of our hands- perhaps with a tinge of guilt as we remember the reds who no longer roam our parkland. But what makes the red so special? It’s just squirrel nationalism gone mad I hear you cry! Both species fulfil a similar purpose in nature, but greys are less fussy and will eat a wider variety of things. They also live longer, thus breeding more, resulting in dense, bark-scoffing populations. The exact environmental benefits of red over grey are unclear, but the red is thought to help spread the seeds of coniferous woodland. Regardless, letting the species die out because of human behaviour is irresponsible. New and more humane methods of population control could allow the slowing down of the grey squirrel population, giving our woodlands- and red squirrels, some room to breathe. The reintroduction of the pine marten, who seems to prefer eating grey over red, could also help give the reds a chance.


HORNET Thought to have arrived in France via a shipping container from China, this beebutcher has appeared to have buzzed over to the UK. Despite some of the scary headlines about this ‘killer’ insect, the Asian hornet is no more aggressive towards humans than the native hornet is. If you’re a honeybee on the other hand… The Asian hornet’s preference for flying insects and honeybees- important pollinators whose numbers have been in decline over the past 50 years- is of course concerning.

Scientific name: Vespa Velutina British name: Buzz-Kill Not to be confused with: Native Hornet. Asian hornets are 2.5- 3cm, mostly black with yellowtipped legs and a gold band near the base of their abdomen. Native hornets are bigger (3- 3.5cm) and more of a browny-yellow colour.

These hornets will wait outside a beehive and mercilessly pick off the unsuspecting inhabitants before dismembering them. Asian honeybees that evolved alongside the Asian Hornet developed a defence mechanism that its European cousin doesn’t have- ‘The Bee Ball’. This involves said bees balling up around the hornet and vibrating so much they essentially cook the hornet with the heat they generate. Gnarly. But unfortunately, this means our native bees and insects are completely helpless. UK bee and wasp populations have been in severe decline due to habitat and wildflower loss, use of certain pesticides and insecticides, as well as parasites and disease. (Side note: Despite being picnicenemy number one, wasps actually play a really important role in our ecosystems by preying on pests that would otherwise snack on crops. Essentially- without wasps, we would have a serious insect problem.) Because of the important role these insects play, (bees are responsible for one third of all food production!) combined with their shrinking population, the government has recognised the need to act fast on the Asian Hornet before it can establish itself. If you see an Asian Hornet, you should report the sighting to the UK Biological Records Centre so the spread of this species can be monitored. Scan the QR code if you think you’ve seen one!


STINK BUG Recently spotted at the Natural History Museum, marmorated stink bugs are the hot new invasive species everyone’s talking about. It gets its name because of the foul ‘almond-like’ smell it emits as a defence mechanism. The stink bug has a varied diet of different crops, fruits and ornamental plants and is a thorough nuisance for farmers in the USA where it has accidentally been introduced. In summertime, the bug likes to attach itself to fruit and suck out patches of juice, leaving brown splodges behind that spoil it. Sometimes, if a stink bug feasts on some grapes, it’s odour can become trapped within them, so when they are crushed to make wine the odour then contaminates the flavour. Yummy. Damage to fruit, wine and crops obviously also has severe economic impact for farmers and food production.

Scientific name: Halyomorpha halys British name: Eww gross! Not to be confused with: Other varieties of shield bug. Stink bugs are a mottled brown with white bands around the abdomen and antennae.

In Asia, where the stink bug is native, there are certain parasitoids such as the samurai wasp that help maintain stink bug levels. But outside of its natural habitat, the stink bug has no specialized predators that have evolved alongside it, leaving the task of controlling populations down to pesticide use. Stink bugs also like to hide in people’s homes over winter as it’s nice and warm, sometimes hundreds at a time, which helps populations to survive. It’s thought that hiding in shipping containers during colder seasons is how the species was able to travel away from its native range over to the USA.

Scientists have also predicted that as the climate gets warmer, it’s only a matter of time before the bug is able to survive elsewhere, including the UK, where it has now been spotted. Pheromone traps are used to help monitor the species to avoid it becoming established and potentially wreaking economic havoc. For more information about bug identification and reporting stinkbug sightings, see the information listed at the back of the guide.

GIANT HOGWEED Scientific name: Heracleum mantegazzianum British name: No thanks Not to be confused with: Regular hogweed or cow parsley. Giant hogweed is much larger, funnily enough, growing up to 10ft tall

Another introduction by the Victorians, Giant Hogweed was brought over from Central Asia and the Caucasus Mountain region to be displayed in ornamental gardens. It became naturalised not long after it’s introduction, with each plant able to spread between 20,000-30,000 seeds, mainly transported by waterways and the wind. Unlike most species listed here, giant hogweed is in fact very harmful to humans. The sap the plant produces causes photosensitive burns to the skin, meaning they are highly reactive to sunlight, causing nasty blisters. (do not Google it, trust me) These burns can sometimes take years to heal properly and if the sap gets in the eyes it can even cause blindness, so don’t touch it! If you’ve come into contact with giant hogweed, it’s best to seek medical advice, but make sure to wash the area thoroughly and keep it out of the sunlight. The smaller species of native hogweed can also cause rashes, but on a much less severe scale.

Control of giant hogweed should always be carried out with full personal protective equipment, so the sap isn’t able to get onto your skin and face (definitely leave this to the experts though.) The Royal Horticultural Society suggests trying to dig out the plants first, to avoid using chemicals, however this is not always a feasible option for large infestations. Because giant hogweed likes to hangout by riverbanks, it’s vital that chemicals don’t end up in the waterotherwise we won’t be doing our riverdwelling wildlife any favours. Sheep and cattle are also effective methods of giant hogweed control! It’s an offense to grow giant hogweed in the wild, and although there is no law that you eradicate giant hogweed on your land, you can get an ASBO for failing to control it.

RING-NECKED PARAKEET Scientific name: Psittacula krameri British name: Screechy Screechicus Not to be confused with: Pigeons. (just kidding) There are all sorts of theories as to how this colourful bird ended up here, one theory being a pair were released by Jimi Hendrix in the 1960s, or possibly that they escaped the film set of The African Queen in the 1950s. A more popular theory however, is that pet parakeets were released or have escaped overtime, resulting in the now substantial populations in London, slowly spreading out to other major cities. Despite usually being a tropical bird, they can survive the harsher winters because of the abundance of food within cities.

They are essentially a more colourful and screechy pigeon. Unlike pigeons however, they are a popular sight for many Londoners due to their exotic and colourful charm, (sorry pigeons) with populations dotted around the city centre from Hampstead Heath to Richmond Park. Because parakeets like to nest in trees, some worry that this puts native birds like woodpeckers and nuthatches without a place to live (and we all know how hard it is to find a house in London.) However, because they are such a recent introduction, it’s unclear as to whether these feathery megaphones pose a significant threat or not. Currently, the government does not support a cull of these birds, despite what the tabloids may say. Conservationists are keeping a close eye on their numbers to ensure they do not become a problem in future.

However, eradication efforts were carried out for the monk parakeet. This South-American native is smaller than the ring-necked and likes to build communal nests on pylons which can cause blackouts and even fires in countries where it is established. Because of this, the government acted quickly to stop the species from naturalising and causing potential damage. For now, the exact ecological impact of the ring-necked parakeet is still pretty undecided, so populations are monitored closely to see if expanding numbers will cause any adverse effects for native birds.

MINK Scientific name: Neovison vison British name: Bitey River-Cat Not to be confused with: Otters, mink are smaller than otters and overall look more ferret-like

Another species native to North America, mink were brought over in the early 20th Century for use in commercial fur farms. Through escaping these farms (who can blame them?) and the odd deliberate release, they have since established themselves in the wild. Mink have thrived in our waterways, doing what mink do best, killing lots of things, sometimes more than they actually need. Despite their adorable appearance, mink are skilled hunters able to kill a whole manner of creatures from insects and fish, to rodents and ducks, one of their favourite snacks being the very endangered water vole as well as ground nesting birds. Don’t blame it all on the mink though- the water vole population hadn’t been doing too well during the 20th Century due to other factors such as habitat loss, industrialisation and pollution, (which also contributed to the decline of the otter) but the establishment of the mink definitely hasn’t helped things. Water voles are recognised as being vital to our waterways by the UK Biodiversity Action Plan (essentially acting as tiny-beavers, but more on beavers later) with their burrowing encouraging diverse plant life to grow along riverbanks, helping the wider ecosystem.

Unlike the bigger native otter, mink can fit inside a water vole burrow and wipe out an entire family very quickly. There is debate about whether otters moving into mink territories can help with mink numbers reducing, as the bigger animal is thought to outcompete the other, but there is also some evidence the two can coexist together quite easily. Control of mink is primarily carried out through regional wildlife trusts and volunteers using live traps, which ensures the wrong animals aren’t caught. Also, by looking after our wetlands, we are helping the water vole- along with all of our other wetland species- to survive.

MUNTJAC DEER Another species introduced by the Victorians to be displayed in country estates, much like the grey squirrel, muntjac were spread around by humans wanting exotic species in their parks. As a result, they have firmly established themselves and have been unpopular with gardeners ever since. As well as being partial to your nan’s favourite flowers, muntjacs are blamed for damaging forests as they like to snack on young shoots, trees and shrubs, preventing the regeneration of woodland, which has a large knock-on effect for other species. (Some people also find their loud ‘bark’ quite scary.) The UK is actually home to six species of deer, of which only the Red and the Roe deer are true natives. (Fallow deer were introduced to the UK by the Normans but aren’t considered as much of a problem.)

Scientific name: Muntiacus reevesi British name: Barking-deer Not to be confused with: Other deer species. The muntjac is the smallest at around 50cm at the shoulder, with small horns and a stripey face. The muntjac is often the poster child for invasive deer species, probably because other species like the Chinese water-deer just sound cooler. But really, it’s probably due to the fact the muntjac is able to spread far more quickly, as unlike other species, they are able to breed all year round. The muntjac can’t be blamed for everything though, deer species as a whole are thought to cause damage to commercial woodland and forestry’s because of their high numbers. Deer are able to reach such high populations in the UK because they have no natural predators left. Britain was once home to wolves and lynx, now extinct due to hunting and deforestation in earlier centuries. Humans don’t need to hunt them for food anymore, either.

Because they have no predators (besides cars) populations are able to grow and potentially cause damage through forest overbrowsing (which is like grazing, but with animals eating fruits, shrubs, shoots and leaves rather than grass.) There has been talk over the years of reintroducing wolves and lynx to help manage deer populations. While these predators aren’t a threat to humans, some farmers and livestock owners have raised concerns. If you’re interested, check out Lynx UK for more information about reintroduction efforts. For now, control of muntjac deer is still carried out through targeted culls. Eradication is not an option, so it’s thought that managing populations to help them coexist with other species is the best approach. The British Deer Society has put together an article about the potential use of contraception to manage populations, a link to which can be found at the back of the guide.


SIGNAL CRAYFISH Scientific name: Pacifastacus leniusculus British name: Ouch! Not to be confused with: The native white-clawed crayfish. Signal crayfish are bigger and more red-ish.

Introduced by the government in the 1970s for food exports as native populations were suffering from the crayfish plague, the signal crayfish quickly escaped fisheries and established itself in the wild. But uh-oh, turns out signal crayfish are carriers of the crayfish plague and can also outcompete the native species for food and territory. The UKs only native crayfish is the smaller white-clawed, the other 6 species are all non-native. (Although, it’s thought the white-clawed may have actually arrived in the middle ages.)

Our waterways are fragile ecosystems that have suffered in recent years due to pollution, climate change, habitat loss and fragmentation (habitat being broken up into smaller, unconnected areas.) It’s thought that the signal crayfishes burrowing erodes riverbanks (as their burrows can be up to 2 meters long) leading to a bigger risk of flooding, with the silt they dig out being put into the water, harming fish and invertebrate populations.

This, combined with disease as well as lack of food and shelter, has severely damaged white-clawed populations which are now listed as endangered. To stop their extinction, the trapping, removing and eating of the signal crayfish has been attempted, but often proven to be ineffective. A recent method in signal crayfish control is to trap and sterilise the dominant males, leading to a decreased population over time. The dominant male crayfish is important in managing populations as they stop the smaller males from breeding and they also eat the younger crayfish.

As the dominant male is the only one ‘allowed’ to breed, sterilising and letting him continue to bully the other crayfish, rather than killing him, helps keep the population down. It’s important that the signal crayfish is not given the opportunity to spread. This means not transporting them to new bodies of water and cleaning equipment that has been in the water to limit the spread of the spores that carry the crayfish plague.

BLACK BULLHEAD CATFISH Scientific name: Ameiurus melas British name: Bull-y Catfish Not to be confused with: Wels Catfish, another non-native species that grows to be much larger, or the Bullhead (Cottus gobio) which is a native sculpin fish.

Introduced in the late 19th Century, with some potentially escaping the pet and aquaculture trades, this catfish is considered a big problem for fisheries. Able to reach high densities, it poses a threat to native aquatic life.

Despite only growing to be about 20cm long, it compensates by shoaling up in gangs for protection, having spikes on parts of its fins that can be used to cut predators. Pretty hardcore.

The black bullhead is part of the ‘mud catfish’ gang, an informal name given to several species of fish that can survive in low oxygen and stagnant waters.

It also likes to eat a lot of other fish and their eggs and will outcompete native species for food.

There is some evidence that the shoaling movements of black bullheads may increase water turbidity (making the water more murky) which can have adverse effects such as loss of visibility and lower oxygen levels for fish. Because of the threat to native fish and the fact they aren’t very big, (not a very impressive catch) means they are not popular with Anglers. Eradication efforts were carried out in 2014 by The Environment Agency on the only known population found in a fishery in Essex.

This was successful, however, there is always the possibility of a few having got away. To ensure the success of their work, The Environment Agency encourages any sightings to be reported to the AquaInvaders mobile app or via email. For links and more information, head to the back.

ZEBRA MUSSELS Scientific name: Dreissena polymorpha British name: Pain-in-the-boatside Not to be confused with: Native mussels. Zebra mussels are small and yellowy-brown with a distinct brown zig-zag pattern on their shell. Imported via trading ships in the 1800s, the population saw a dramatic increase at the turn of the 21st century, where they now inhabit parts of southern and eastern England. Zebra mussels form dense colonies, with a single mussel able to produce up to 1 million eggs by itself, making them highly effective spreaders. Human activity and recreational boating are the primary reason they are able to travel so far.

The mussels can latch onto the side of a boat and be transported across waters, with larvae able to get inside boating and fishing equipment. Ballast water (water held inside the tank of cargo ships for stability which is then pumped out) is another way for the species to be introduced to new waterways.

As populations of zebra mussels are so dense, they can clog boat filters, water treatment pipes, boat hulls and just about anything they can latch onto (including native mussels) making them very hard to get rid of. This then causes economic repercussions as they take time and are expensive to remove. Zebra mussels also increase water clarity, which sounds like a good thing, but it actually encourages the growth of weeds and drastically alters the ecosystem. As well as this, they’re also pretty good at outcompeting native species for food.

As zebra mussels are so hard to eradicate, prevention is the best method to stop the spread of the species. The Non-Native Species Secretariat (NNSS) recommends that boaters and anglers should follow the policy of ‘Check, Clean, Dry’, which is: checking your equipment for any mud, animal or plant life and leaving it at the site you found it, cleaning the equipment with hot water and to dry it for as long as you can before you use it again. For more information, check out the links at the back of the guide.

AMERICAN BULLFROG Scientific name: Pacifastacus leniusculus British name: ‘Look at the size of him!’ Not to be confused with: Native common frog. The bullfrog is about double the size of the native species, up to 25cm long.

Although the species is not widespread in the UK, the bullfrog serves as a great example of why you don’t release pets into the wild. Eating anything smaller than itself, (and often its own species) the bullfrog poses a significant threat to native amphibian life. As well as eating both the native species and their food sources, bullfrogs may also carry a type of fungus that can spread disease to other amphibian life. According to the NNSS, control and monitoring costs of the species so far is estimated to be well over £100,000. Alligators, turtles and water snakes will snack on bullfrogs, which fortunately for the bullfrog, are all animals definitely not found within the UK.

The bullfrog’s lack of predators and tendency to relocate themselves because of fierce competition (and cannibalism) from other bullfrogs makes them great spreaders, meaning they are hard to eradicate. Because of the bullfrogs size, the species has often been imported into other countries for their leg meat. This, along with pets being deliberately released, has contributed to established populations outside of their natural range in Europe, Asia, as well as other parts of the USA, where they are able to chomp their way to the top of the food chain. Control of the bullfrog has been carried out through trapping and the draining of ponds to remove the tadpoles as well as the adult frog.

However, similarly to the grey squirrels and signal crayfish, the capturing and re-releasing of sterilized male frogs is a new method of control that will hopefully help slow populations without any risks to other species. Bullfrogs are bigger than the native frog, growing up to 25cm in length, compared to around 6-10cm for the native frog.

Bullfrog tadpoles are easily identified as they are flipping massive at 15cm, much larger than the native tadpole. If you think you’ve spotted a bullfrog in the wild, report your sighting to the UK Biological Record Centre. You can find a link to this at the back.

MAKING A COMEBACK Efforts to bring back some of the species lost due to human activity have gained popularity in recent years, thanks to increased public interest in the rewilding movement. Here are a few species that have been, or are starting to be, reintroduced back into the UK:

BEAVER Castor fiber

Beavers were hunted to extinction for meat, fur and their scent gland castoreum, sometime around the 16th Century. The beavers dam-building ability is a great method of natural flood defence and they fill an important ecological role. The majority of beaver populations are currently in Scotland and in carefully monitored trial populations dotted around Devon, Cornwall and Kent.


Milvus milvus

The red kite is a great success story. Hunted and threatened by egg-collectors to nearextinction in the 20th Century, remaining populations were able to just about hang on in Wales, but almost disappeared elsewhere. Reintroduced around 30 years ago, populations have now soared to about 2,000 breeding pairs. The kite is still threatened through poisoning, either from rodenticides or by bait left from farmers wanting to target foxes.

PINE MARTEN Martes martes

A member of the Mustelid family which includes badgers, otters and mink, the pine marten population has been mostly confined to Scotland. Gloucester Wildlife Trust has recently reintroduced the species back into the Forest of Dean, after hunting and loss of habitat saw them disappear in the late 1800s. Pine martens are thought to help manage woodland ecosystems by snacking on the grey squirrel.

WHITE-TAILED EAGLE Haliaeetus albicilla This majestic bird can reach a wingspan of up to 2.5m long and pair-bonds for life with its chosen mate. They tend to be found around coastal areas (they are a type of sea-eagle) and again are primarily found in Scotland but are gradually being reintroduced in England. They disappeared as a result of human persecution in the early 1900s and several reintroduction efforts have been tried over the decades but finally, they are making a comeback. The white-tailed eagle is still at risk from deliberate human persecution and accidental poisoning from farmers protecting livestock, so populations and nesting sites are monitored very closely.

FURTHER READING & RELATED ORGANISATIONS AquaInvaders (app) by Natural Apptitude aquainvaders/id697986169 Asian Hornet sighting page: hornet British Bugs: Online bug identification guide Bullet or Needle? Peter Green examines the potential role of contraception in the management of wild deer populations: uploads/2021/01/Bullet-or-Needle_Deer-AUTUMN_2019.pdf Bullfrog sighting page: Check, Clean, Dry: Advice for stopping the spread of non-native species through the water. Environment Agency Email for Non-Native Species: non-natives@ Invasive Aliens by Dan Eatherly (2019) William Collins (book) iRecord: General non-native species sightings: Lynx UK: Organisation working to re-establish the Lynx in Britain. www.lynxuk. org Natural England: Government adviser for the natural environment in England. Natural History Museum Biodiversity Facebook group groups/NHMUKBiodiversity

Natural History Museum: Information on wildlife and invasive species (as well as dinosaurs) Non-Native Species Secretariat: Essentially the UK’s invasive species encyclopedia. Rewilding Britain: Country-wide organisation focused on rewilding. www. River Otter Beaver Trial Report: files/2020-05/River%20Otter%20Beaver%20Trial%20-%20Science%20and%20 Evidence%20Report.pdf RSPB: Fantastic birds and where to find them The Amphibian and Reptile Conservation Trust: Learn all about these species and how to protect them The British Deer Society: Promoting deer education, research and management The Deer Initiative: Committed to sustainable and humane ways to manage deer populations. The Wildlife Trusts: Lots of information on British wildlife, animal identification, articles, petitions and much more. The Woodland Trust: Dedicated to restoring, protecting and planting Britain’s forests. UK Biological Records Centre: Information on researching and recording nature Zebra Mussel sighting page:


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RSPB: (n.d). White tailed eagle. Available at: our-work/conservation/conservationand-sustainability/safeguardingspecies/case-studies/white-tailed-eagle/

BirdLife International. (2017). New study reveals why islands are our biggest extinction battlegrounds. Available at: worldwide/news/new-study-revealswhy-islands-are-our-biggest-extinctionbattlegrounds

Invasive Species Compendium. (n.d). Ameiurus melas (black bullhead). Available at: datasheet/94466 National Geographic. (n.d). American bullfrog profile. Available at: https:// amphibians/facts/american-bullfrog

Science Daily. (2019). Rising global shipping traffic could lead to surge in invasive species. Available at: releases/2019/03/190318121043.htm

Conservation Evidence. (2004). The effects of re-introduced otters Lutra lutra on densities of American mink Mustela vison, Oxford, England. Available at. https://www.

National Wildlife Crime Unit. (n.d). GB Non-Native Species Secretariat North American Bullfrog information sheet. Available at: https://www.nwcu.police. uk/wp-content/uploads/2017/10/ID_ Lithobates_catesbeianus_Bull_Frog.pdf

BBC News. (2020). UK government backs birth control for grey squirrels. Available at: news/science-environment-55817385

Discover Wildlife. (n.d). 17 invasive species causing problems in the UK. Available at: https://www. Eatherley, D. (2019). Invasive Aliens. HarperCollins. Froglife. (n.d). American bullfrog profile. Available at: https://www. Game and Wildlife Conservation Trust. (n.d). Muntjac profile. Available at: Game and Wildlife Conservation Trust: (n.d). Mink in Britain. Available at: research/mammals/american-mink/ mink-in-britain/ GB Non-Native Species Secretariat. (n.d). Check, clean, dry information page. Available at: http://www. index.cfm GB Non-Native Species Secretariat. (n.d). List of species alerts. Available at: index.cfm Gov.UK: Marine Science Blog. (2015). EA eradicating the black bullhead catfish from Great Britain. Available at: https:// eradicating-black-bullhead-catfish/ Inland Waterways Association. (2017). Signal Crayfish Profile. Available at: news/signal-crayfish

Natural History Museum. (2020). Why Asian hornets are bad news for British bees. Available at: https://www.nhm. Natural History Museum. (2021). Brown marmorated stink bugs arrive in the UK and pose threat to crops. Available at: news/2021/march/monitoring-stinkbugs-to-anticipate-the-future.html (2017). Invasive species on the rise globally. Available at: https:// Practical Fishkeeping. (n.d). Zebra Mussels invade Thames. Available at: fishkeeping-news/zebra-mussels-invadethames/ Rewilding Britain. (n.d). Eurasian Lynx profile. Available at: https:// rewilding-superstars/eurasian-lynx?gclid =Cj0KCQjw1PSDBhDbARIsAPeTqre_1p tYtZBwvMUbq4NS-J-o6O6N874aloI8HAxkJnNnjaZYAUr9mEaAqFREALw_ wcB Rewilding Britain. (n.d). Wolf profile. Available at: https://www. rewilding-superstars/eurasian-wolf RSPB: (n.d) Red kite conservation. Available at: birds-andwildlife/wildlife-guides/bird-a-z/red-kite/ conservation/ RSPB: (n.d). Common frog profile. Available at: uk/birds-and-wildlife/wildlife-guides/ other-garden-wildlife/amphibians-andreptiles/common-frog/#

The Biome Podcast. (2020). #1 The Beaver Reintroduction | The Biome Podcast. Available at: https://www. The Biome Podcast. (2020). #20 White Tailed Sea Eagles | The Biome Podcast. Available at: com/watch?v=NiCUBeoxvWs&list= PLtXw4rNDi53-lfHSleVbCq5CqJ_ wEKcf8&index=2 The British Deer Society. (n.d). Muntjac profile. Available at: https://www.bds. deer-species/muntjac-deer/ The Canal and River Trust: (n.d). Signal crayfish profile. Available at: the-rogues-gallery-of-invasive-species/ signal-crayfish The Canal and River Trust: (n.d). Zebra mussel profile. Available at: the-rogues-gallery-of-invasive-species/ zebra-mussel The Canal and River Trust: (n.d). American Mink profile. Available at: the-rogues-gallery-of-invasive-species/ american-mink#:~:text=American%20 mink%20first%20arrived%20in,of%20 escapees%20and%20deliberate%20 releases.&text=Mink%20numbers%20 have%20increased%20rapidly,are%20 now%20common%20and%20 widespread. The Conversation. (n.d). Invasive Species: why Britain can’t eat its way out of its crayfish problem. Available at: The Guardian (2019). The great green expansion: How ring-necked parakeets took over the UK. Available at: https:// jun/06/the-great-green-expansion-howring-necked-parakeets-took-over-london The Royal Horticultural Society. (n.d). Giant Hogweed Profile. Available at: profile?pid=458

The Royal Society for the Protection of Birds (RSPB). (n.d). Ring-necked parakeets in the UK. Available at:


The Wildlife Trusts. (2019). Pine Martens reintroduced to England. Available at: https:// The Wildlife Trusts. (2020). Beavers Build Back Better – but their future is not secure. Available at: news/beavers-build-back-better-their-futurenot-secure The Wildlife Trusts. (n.d). American Mink profile. Available at: https://www.wildlifetrusts. org/wildlife-explorer/mammals/american-mink The Wildlife Trusts. (n.d). Muntjac profile. Available at: wildlife-explorer/mammals/muntjac-deer The Wildlife Trusts. (n.d). Red kite profile. Available at: wildlife-explorer/birds/birds-prey/red-kite The Wildlife Trusts. (n.d). Saving species: Water vole. Available at: https://www. saving-species/water-voles The Wildlife Trusts. (n.d). White-tailed eagle profile. Available at: https://www.wildlifetrusts. org/wildlife-explorer/birds/birds-prey/whitetailed-eagle The Woodland Trust. (n.d). Giant Hogweed: The Facts. Available at: advice/profile?pid=458 The Woodland Trust. (n.d). Grey Squirrel Profile. Available at: https://www. animals/mammals/grey-squirrel/ UK Squirrel Accord. (2020). Fertility control research. Available at: https://squirrelaccord. uk/squirrels/fertility_control/

Trea Renaut-Buttle is an Illustrator from Norfolk, England. Having spent an embarrassing amount of time as a teenager stalking wildlife (particularly owls) with her camera, her fascination with the natural world plays a large part in her illustrative work today. Studying Illustration + Graphics at Coventry University, she discovered a love of creating colourful and engaging visual communication to brighten up text and information.

UK Water Industry Research. (2015). Reassessing the risk and control of zebra mussels in the UK water industry. Available at:

Sometimes Cute (but very often extremely) Deadly, is a guide to help raise awareness about environmental issues in a fun and informative way.

ZSL. (2019). Understanding the origin of the ring-necked parakeet in the UK. Available at: doi/full/10.1111/jzo.12753

You can reach Trea at: @trea.rb

DID YOU KNOW? One the biggest threats to wildlife alongside climate change are invasive species. It’s thought that Britain is home to over 3,000 animals and plants that are classed as non-native, the vast majority of which pose no threat to our native flora and fauna despite having evolved separately. The rise in global transport and human interference has seen a surge in new species having arrived over the years, with some causing incredibly damaging effects on our delicate ecosystems. This guide will introduce you to some invasive wildlife that may be cute, but are very often extremely deadly…