Dear Readers, this week we had Claire with 11 1/2 out of 15 and Fran and Bobby Freelove with 13 1/2 out of 15, so well done to all of you! The next quiz will be tomorrow, and I am wondering why I didn’t have the idea for it ages ago…I hope you enjoy it!

‘Alien’ animals can cause a range of reactions, but the history of how they got to the UK, and what their impact has been, fascinates me. In most cases, they arrived because we wanted them, and didn’t realise quite how keen they’d be to get back to the wild. Sometimes, they were hitchhikers, a result of the international trade in plants and artefacts. Very rarely, they flew here of their own accord and found the conditions to their liking. With climate change, and with our inadequate biosecurity regulations, we are going to have to get used to all manner of plants and animals arriving and setting up home. As always, it will be interesting to see how such encounters play out.

This attractive little rodent was deliberately released into the wild in 1902 (it comes originally from southern and central Europe). It is considered a menace because it can wreak havoc in lofts and roof spaces, and damages trees by stripping the bark. The Romans used to have special pots for keeping edible dormice until they were fat enough to eat. I must admit I thought that they had brought them to the UK, but it seems that if so they became extinct, and were re-introduced much more recently.

Farmed for their fur, some escaped while others were deliberately released, sometimes by well-meaning animal activists. However, these creatures are efficient predators, and their presence has been linked to the decline of the water vole and various ground-nesting birds. Their numbers might be decreasing slightly as the larger otter becomes more common.

Originally introduced to populate the grounds of stately homes and estates, the sika was established in the wild by the 1930’s. It interbreeds with native red deer and can cause serious damage to crops, trees and sensitive habitats. There are lots in Dorset, and on our way back from Dorset last week our train nearly ran over two who were on the tracks.

This animal (which is a canid not a raccoon) was introduced to the UK from East Asia for its fur. it isn’t established in the UK yet, but it is well established in many other parts of Europe so watch this space. Where it has established a foothold, it is a predator of birds and amphibians, and competes with native carnivores such as the fox and badger.

Did Jimi Hendrix release a pair of these while he was on an acid trip, resulting in the many thousands of birds that are now common in London? It’s more likely that there were escapes and releases from multiple sites over a period of years. At any rate, the parrot is now moving north and west at an inexorable rate. It strips orchards and may compete with other hole-nesting birds, but personally I think that it brings a touch of the exotic to North London.

This medium-sized goose has been breeding in the wild after escaping from wild fowl collections since the early 1800’s, but has increased like billy-o since the 1980’s. It is well-established in the wild in Suffolk and Norfolk, and seems to be going west at a rate of knots. It can cause crop damage and pollute water bodies, but to be honest so can most wildfowl at high concentrations. Plus, to be complaining about pollution of water bodies when there’s so much agricultural and industrial run-off seems a bit hypocritical. Interestingly, they often seem to nest in hollow trees, which is quite a feat for a large aquatic bird.

I was only writing about these animals earlier this week. They can’t breed in the UK (yet) because the winters are still too cold, but individuals can live for up to thirty years, and there seems to be no limit to the number of people prepared to throw their pets into the nearest water body when they get too big. They are voracious predators of amphibians and invertebrates, even taking ducklings when they are tiny.

Deliberately introduced by the end of the 19th century, this chap is also known as the laughing frog because of his loud call. The frog is now well-established in Romney Marsh in Kent, the Somerset levels and the area around Tamworth. The species is apparently becoming more common, so keep an eye open….

This enormous fish, which can grow to 5 metres long and weigh 300kg, was deliberately introduced as a food fish. Hah! By the 1950’s it was swimming happily in managed stillwaters used by fisheries, and in some deep lowland rivers. It eats anything and everything, from frogs to water voles to ducks, and as you can see, there’s nothing in UK rivers that can outcompete it.

The trout that made river fish available to the general public when fish farming really took off in the 1970s in the UK, rainbow trout seem to have problems breeding in the wild in the UK, and are still usually out-competed by the local brown trout. However, climate may be a factor in keeping them in check, and this is changing as we know. Again, watch this space.

Introduced from North America in the 1970s, this crayfish quickly found its way into the wild, and has caused the rapid decline of the native white-clawed crayfish through competition for food and other resources. It also spreads crayfish plague (who knew there was such a thing?) As if that wasn’t enough, it makes its burrows in the banks of water bodies, causing them to collapse, and eats the eggs and young of fish. There is a move afoot to persuade the UK public to eat more crayfish.

This much-maligned beetle comes originally from Asia, and was deliberately released in Europe as a biological control, presumably against aphids. Sadly, the harlequin ladybird is much more of a generalist predator than that, and when the aphids are gone it will turn its attentions to other insects, including the much smaller native ladybirds. It arrived in the UK in 2004 and made itself very much at home ever since. I think personally that it outcompetes other ladybirds than rather than actually eating them, but that’s anecdotal, based on a couple of years observation of one aphid-infested buddleia.

Oh lord the column inches devoted to this insect! It is true that it eats honeybees, but I suspect that it has been the cause of the death of more European hornets, hoverflies, wasps and native bees than any other creature. It is seen fairly regularly in the Channel Islands now, and I believe it’s also been spotted in Cornwall. It arrived in south-western France in some pots imported from Asia. It’s most likely to be spotted in areas where honeybees are kept, but it is still very unlikely to be seen in most of the UK. It is much darker in colour than our native hornet.

This is the tiny creature responsible for our horse chestnut leaves become dry and crinkly and dropping off early every year. Little is known about it, except that it arrived as recently as 2002 on some imported plants, and has been spreading north and west ever since. Though it makes the trees look ugly, it doesn’t yet appear to affect their long-term health.

This little darling appeared in 2006 as a contaminant of imported plants and trees – it’s native to northern France. London appears to be the epicentre of its population at the moment, maybe because of a concentration of oak and hornbeam forest, which it seems to like (our local Coldfall and Cherry Tree woods have both had infestations recently). The insect can be a major defoliator of trees, and its hairs can cause allergic reactions and skin irritation. It can also cause the eradication of populations of innocent caterpillars such as those of the ermine moth (which forms nets in bird cherry and some other trees, but causes no long term harm). Don’t just take a flamethrower to your tree, people!

Photo Credits

Photo One by Bouke ten Cate, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons

Photo Two by Ryzhkov Sergey, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons

Photo Three by Lilly M, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0>, via Wikimedia Commons

Photo Four by Prue Simmons, CC BY 2.0 <https://creativecommons.org/licenses/by/2.0>, via Wikimedia Commons

Photo Five by Bernard Spragg. NZ from Christchurch, New Zealand, CC0, via Wikimedia Commons

Photo Six  By Andreas Trepte – Own work, CC BY-SA 2.5, https://commons.wikimedia.org/w/index.php?curid=788401

Photo Seven By Rhondle – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=16504721

Photo Eight by Charles J. Sharp, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons

Photo Nine by Dieter Florian (To contact the author, ask the uploader or take a look at tauchshop-florian.de.), CC BY-SA 3.0 DE <https://creativecommons.org/licenses/by-sa/3.0/de/deed.en>, via Wikimedia Commons

Photo Ten by Liquid Art, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons

Photo Eleven by David Perez, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0>, via Wikimedia Commons

Photo Twelve by David Short from Windsor, UK, CC BY 2.0 <https://creativecommons.org/licenses/by/2.0>, via Wikimedia Commons

Photo Thirteen by Charles J. Sharp, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons

Photo Fourteen by David Short from Windsor, UK, CC BY 2.0 <https://creativecommons.org/licenses/by/2.0>, via Wikimedia Commons

Photo Fifteen by Kleuske, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0>, via Wikimedia Commons