Exploring the Endemic Wildlife of the British Isles

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The British Isles boast a diverse array of wildlife species unlike any other. This incredible biodiversity owes its existence to a mix of historical, climatic, and geographical factors. Over millennia, the British Isles have experienced a series of glaciations that shaped the landscape and drove the evolution of unique subspecies. Being cut off from mainland Europe has allowed these islands to become a sanctuary where endemic wildlife species can thrive and adapt.

In this article, we’ll dive into the endemic species found in the British Isles and discover their crucial roles in supporting local ecosystems.

What is an Endemic Species?

The official definition of an endemic species is one that only occurs naturally in a very specific location. Outside of this, the species is not found naturally in the wild. Usually these species are found in places like mountains or on islands, like the British Isles. On a much wider scale, some species can be endemic to entire countries or continents. For example, the presence of the kangaroo on both mainland Australia and the island of Tasmania.

What’s interesting about endemic species is that, because of their limited range, they are perfectly adapted to the local conditions. Of course, these adaptations, such as growing denser fur to survive in cold conditions, evolve over thousands, if not millions of years.

You’ll notice that most endemic species are listed as being vulnerable, and many are threatened with extinction. This is due to the fact that they have a very limited range and would struggle to survive outside of this range. What’s more, because endemic species have adapted perfectly to their conditions, any disruption or sudden change can threaten their very survival.

Because of their sensitivity to their environment, endemic species can make excellent bioindicators that tell us a lot about the health of a particular ecosystem. Although, according to research, this is best done when coupled with observations of other species at the same time. What’s more, by looking at how these animals have evolved over time, we’re able to get a good idea of how the geography and conditions in a specific location have changed over time.

Vital Role of Endemic Species in Local Ecosystems

As I touched upon in the previous section, endemic species are often used as indicators of the health of an entire ecosystem. Since they’re very sensitive to change, endemic species will usually be one of the first to be affected so scientists are able to spot problems before they get out of hand and take the appropriate conservational measures.

Since many endemic species are endangered, conservation efforts to protect them are common. The effects of climate change are projected to have the worst effect on endemic species but with efforts in place, these benefit not only the endemic species, but others within the same ecosystems. And it’s important that we take all species into consideration since the loss of any endemic species in an area could have catastrophic effects on the rest of the ecosystem.

Take the snow leopard, for example, which is endemic to the Himalayas and is an apex predator. If this species was to significantly decline in number or even die out completely, it would no longer keep the population of its prey species in balance. If these animals, such as deer, were allowed to increase greatly in number, they would overgraze on grasses and vegetation.

This isn’t the only important role that endemic species play; in fact, each species has its own job that helps to keep the ecosystem in check. For example, some species of bats, birds, and insects play a role as a pollinator. Without them, the plants that rely on them would struggle to survive. Mammals may disperse seeds which also aids in plant reproduction, and a lack of their presence would have similar devastating effects on plant biodiversity.

Endemic Species of the British Isles

1. Scottish Wildcat (Felis silvestris grampia)

The Scottish wildcat is a feline species similar in appearance to the domestic cat. The main differences include size, with the Scottish wildcat being much larger, weighing up to 16 lbs (7.3 kg), and their robust build. What’s more, wildcats can be distinguished by their striped appearance and black-tipped bushy tail.

Scottish wildcats were once found all over Britain but went extinct in the south of the island in the 16th century. Today, they’re mainly found in the Scottish Highlands in areas like Aberdeenshire and the Cairngorms, where they inhabit woodlands and forest edges. Mainly staying alone, this solitary species can become very territorial, which is true of many cats. They’ll mark their territory using scents which could cover up to 1.3 square miles (3.37 square km) for a single adult.

Hunting under the cover of darkness, the Scottish wildcat feeds on a diet of rodents and small mammals as well as birds. Like most felines, they have incredible hunting skills, which they learn from their mother at around 10 to 12 weeks of age.

Scottish wildcats are known for their aggressive tendencies when hunting, and there are stories of humans getting on the wrong side of them in zoos. However, with so few (only around 100) left in the wild and this cat’s elusive nature, humans rarely come into contact with them. 

With such low numbers, there is a real risk of losing the Scottish wildcat forever, which would be devastating since they’re essential in controlling rodent populations and other prey species. What’s more, they’re used as an indicator species that tells us about the health of the local ecosystem.

While things might look critical, there are plenty of conservation efforts in place to try and save these beautiful creatures. For example, projects that involved breeding domestic cats with the Scottish wildcat as well as other captive breeding programs, are ongoing. However, there are concerns over cross-breeding the species with domestic cats, as this could result in inbreeding and losing the genetic purity of individuals in the wild.

There are other efforts in place to educate people on the importance of retaining a healthy habitat for these animals and thankfully, the Scottish wildcat is protected by law. Under the Conversation Regulations 1994, it is illegal to capture or harm one of these animals.

2. Scottish Crossbill (Loxia scotica)

The Scottish crossbill is a medium sized species of passerine finch found primarily in the Caledonian pine forests. Two other species are found in the same region; the red crossbill and the parrot crossbill and it’s believed, by some, that the Scottish crossbill is a race of these two species. What’s super interesting, and rather adorable, is that the species is differentiated (as of 2006) because of its unique song, which some say makes them sound like they have a Scottish accent!

Scottish crossbills have distinct sexual dimorphism, with males being red with black markings, while the females have a more olive to brown coloration. However, it’s thought that crossbreeding does take place in the wild with other crossbill species, so it can be difficult to know if you’ve spotted a pure Scottish crossbill.

This species of bird takes its name from the fact that it has a unique crossed bill, which allows it to extract pine cone seeds, which form the main part of its diet. Because of this diet, the Scottish crossbill is vital within its ecosystem as a seed disperser, helping to ensure the even distribution of trees.

But sadly, their numbers are dwindling, and it’s thought that there could be as few as 20,000 left in the wild. What’s more, this number could be affected by the crossbill’s breeding habits, which see it only breeding (laying between 2 and 5 eggs per clutch) when there is sufficient food availability. Unlike other birds, there is no set breeding season. According to research, periods of heavy rainfall and other effects of climate change have affected the crossbill’s ability to successfully breed. 

Much of the decline of this species can be attributed to habitat loss and degradation. However, the production of pine cones has also been affected as a result of climate change. But conservationists are looking at ways to restore habitat and protect the Caledonian forests.

3. Red Grouse (Lagopus lagopus scotica)

The red grouse is found in Great Britain and Ireland, particularly in Scotland and inhabits heather moorlands; heather forms the primary part of this species’ diet but they also feed on insects and berries. Part of the grouse family, these birds have a similar size and shape to a chicken with deep red feathers, which are bolder in the males. Since they often inhabit upland areas, the feathers on their legs are a unique adaptation that helps them to resist the cold temperatures.

What’s more, they’ve adapted the unique ability to alter the color of their plumage during winter to blend in with the snow. They’re usually solitary birds but, when things get very cold, they can often be seen in small flocks, sharing body heat. Despite these adaptations, red grouse don’t breed in a consistent manner. In fact, their populations tend to fluctuate and usually reach their peak between every seven to ten years. 

When it comes to breeding, male red grouse engage in lekking behavior where several males will ‘perform’ to win the affection of a female. Pairs are usually formed in fall, and the females will lay up to 9 eggs in spring. However, there are concerns that this species is mating with the willow ptarmigan, which could upset the genetic purity of the red grouse.

The red grouse is listed as green under the Birds of Conservation 5, but they do face several threats. For example, deer are known to overgraze in the red grouse’s habitat, which has led to habitat loss. What’s more, this species is susceptible to grouse disease which is caused by a parasite known as Trichostrongylus tenuis. However, there are conservation efforts in place to try and control the spread of this disease. 

Conversation projects include predator control and the controlled burning of heather to encourage new growth, which provides new habitat and resources for the red grouse. 

This is important for the local ecosystem as the red grouse is a keystone species whose eating habits keep heather under control. What’s more, red grouse are essential prey for larger animals, including eagles and foxes. But humans also benefit from their presence, and red grouse shooting has been a popular sport for centuries in the UK. For landowners, this carries important economical significance, especially since the red grouse is one of the most prominent birds hunted after the Glorious Twelfth; the beginning of shooting season in Scotland. 

4. Scottish Red Deer (Cervus elaphus scoticus)

The Scottish red deer is a stunning animal that is found in the Scottish Highlands and islands as well as in some southern parts of England and Counties Kerry and Donegal in Ireland. It can be found in various habitats, including grass and moorlands as well as forests. Here, they feed on a diet of sedge, heather, grass, and woody plants. Because of their feeding habits, Scottish red deer are important in shaping and maintaining the local environment. However, being a prey species to animals like the Eurasian lynx, they also ensure a healthy dynamic.

One of the most interesting things about the Scottish red deer is that it is considered to be one of the largest deer species on the planet, although somewhat smaller than the western European red deer. In any case, these majestic creatures can stand up to 5.9 feet (1.8 meters) in height and weigh as much as 331 lbs (150 kg).

Males have beautiful antlers, which they largely use for defending territory. In July, they can be seen rubbing their antlers on trees to remove dry velvet which changes the color of their antlers from white to chestnut brown. The antlers tell us a lot about an individual, indicating its age and health depending on their size and condition. Males also boast an impressive mane during breeding season, which they use to attract females along with loud roaring calls and fights with other males in an event known as rutting season. This attracts a lot of tourists who come to observe this amazing aspect of nature every year. 

It’s estimated that there are around 140,000 Scottish red deer left in the wild, and this is because of challenges such as agriculture and forestry as well as overpopulation. That said, this species is known for its migratory habits from upland to lowland areas according to available food sources. This typically happens during winter when the red deer’s coat will also thicken to protect it from the cold.

Scottish red deer are also hunted for sport and in some areas, deer culls take place. But they are afforded protection by several UK laws, including the Deer Act 1996. What’s more, conversation efforts are in place to help restore and protect their habitat, especially since climate change has seriously affected the availability of food for these deer.

5. Irish Hare (Lepus timidus hibernicus)

The Irish hare has a very limited range on the island of Ireland within the British Isles. However, here, it does inhabit various regions, including farmlands, grasslands, and coastal dunes. Being a species of mountain hare, it’s no surprise that it’s also found at higher elevations.

Irish hares rely on a herbivorous diet which includes things like heather, grasses, and leaves. However, during winter, they will adapt their diet to include woody items like twigs and bark to help them survive when other food sources are limited. Because of their diet, these animals are essential to their ecosystems as they shape and maintain the vegetation.

While this is a subspecies of the mountain hare, Irish hares tend to be much smaller. Their coloration is typically reddish-brown during the summer months. Unlike some other hare species, they do not turn completely white in winter. Instead, they may undergo a seasonal change in coloration, with their fur becoming somewhat lighter or grayer in winter. This adaptation helps them blend into their surroundings in both summer and winter, providing effective camouflage.

Irish hares are not usually found in groups and tend to live a solitary life. However, they will join together for breeding and females are known to reproduce once every month! During breeding season, the females, which are typically larger than their male counterparts can be seen boxing their potential mates. Once the leverets are born, they remain with their mother for around 21 days and, in the wild, they can live between 3 and 4 years.

That said, there are concerns over the status of the Irish hare which is protected under many UK and Irish laws and has been since the 1930s. This includes the Wildlife Amendment Act 2000, as well as many others.

Problems faced by the Irish hare include habitat loss because of things like agriculture and changes in land use, although there are lots of conservation programs in place to help restore and maintain lost habitat. This is important not only for the survival of the Irish hare, but also other species. Since Irish hares are prey for larger animals, their demise would have a significant impact across the food web.

Another issue is that Irish hares have been known to interbreed with brown hares, which upsets the genetics of the wild populations. However, conservationists are monitoring populations and recording results to learn how to better manage these animals and protect them.

6. St Kilda Wren (Troglodytes troglodytes hirtensis)

Perhaps one of the most northerly endemic species of the British Isles, the St Kilda wren is found only in the St Kilda archipelago, which lies 40 miles (64 km) off the coast of the Outer Hebrides. It’s truly remote. Here, they can be found in various habitats, including grasslands, rocky cliffs, and heathlands where they forage for insects and spiders. This means that these birds play an important role in controlling insect populations on these islands.

The area in which the St Kilda wren lives poses some serious challenges in terms of weather and conditions, but these birds are perfectly adapted to survive here. For example, they’re able to hunt for insects in rocky crevices and even breed in these conditions.

Telling the St Kilda wren apart from mainland wrens is typically easy; they tend to be lighter in color with heavy barring, and their song much louder and more prominent. It’s often described as cheerful and is used to communicate dominance and for attracting a mate. What’s more, this species is generally much larger than its mainland cousins.

Sadly, the population of St Kilda wrens within its endemic region is quite low largely because of the threats posed by introduced species as well as habitat changes. Climate change is also an issue, but it’s important we protect these birds as they help to maintain the predator/prey balance, being prey for creatures like birds of prey.

The good news is that the St Kilda archipelago is protected as it is a UNESCO World Heritage Site. Furthermore, there are ongoing conservation efforts in place that aim to protect the habitat and biodiversity of this unique location.

7. Shetland Wren (Troglodytes troglodytes zetlandicus)

Shetland wrens are found exclusively in the Shetland Island group, located between Orkney, the Faroe Islands, and Norway, off the coast of Scotland. These birds inhabit various areas of the islands, including along the coast as well as in woodlands and heathlands. They can often be seen foraging among the leaf litter for their next meal.

For the most part, the Shetland wren will breed and lay its eggs on boulder beaches but at other times of the year, they may venture further inland. These small brown birds can be heard on the beaches emitting their loud, melodious calls, which are used to attract mates and defend territory. It’s thought that the song is louder than other species of Eurasian wren, so it can be better heard on the rocky beaches.

Compared to mainland wrens, this species is much darker. They have compact bodies and are perfectly adapted to handle the cold, harsh conditions this far north with traits such as a stout beak and strong legs. You’ll also notice that, like many island birds, the Shetland wren has a much shorter tail and wings.

Sadly, it is estimated that there may be as few as 1500 Shetland wrens left in the wild and this is largely a result of their limited range. However, they are important for insect control owing to their diet of insects and spiders as well as small aquatic organisms and as a prey species, so it’s essential that they’re protected. What’s more, these birds contribute to the unique biodiversity of the Shetland Islands, which are recognized as a wildlife haven. Within this island group, there are three main conversation areas that aim to protect the plant and animal life found here.

8. Fair Isle Wren (Troglodytes troglodytes fridariensis)

If you thought that the St Kilda and Shetland wrens had a limited range then wait until you meet the Fair Isle wren. This is a species of Eurasian wren that is only found on Fair Isle, located between the Orkney and Shetland Isles of Scotland, which covers an area of just over 2.7 square miles (7 square km). Here, they inhabit various areas, including along the rocky coast, where, just like the St Kilda wren, they forage for insects and spiders.

The species is so limited that it was only discovered in 1951 and is considered to be the least numerous species of endemic bird in the UK, potentially even in Europe. In fact, reports suggest that there may be as few as 50 individuals on the island at any one time.

Fair Isle wrens often breed on the boulder beaches where they are also seen looking for food. Their diet consists of both seaweed as well as coastal creatures like sandhoppers, fly larvae, and small crustaceans.

Fair Isle is one of the best birdwatching spots in the UK as it has been designated as an Important Bird Area, which means it is given additional protection. 

9. St Kilda Field Mouse (Apodemus sylvaticus hirtensis)

Found in the St Kilda archipelago, this is a subspecies of the wood mouse that is thought to have inhabited the fields and grasslands of the islands for the last 1000 years. It seems to have thrived here since humans decolonized the islands back in the 1930s. The only human presence here now is that of the military.

These field mice feed primarily on a diet of insects as well as snails and various vegetation like moss and grass. Since there is very little competition for food, they benefit from having the lion’s share. What’s more, it’s reported that the St Kilda field mouse has very few natural predators on the island, which has allowed it to thrive for such a long time. On the other hand, studies have shown that its relative, the St Kilda house mouse has rapidly declined in number on the islands.

In any case, the St Kilda archipelago is protected under the Scottish National Trust, and it is also a UNESCO World Heritage Site, so the outlook for this species appears to be positive, which is sadly not the case for a lot of endemic animals.

10. Orkney Vole (Microtus arvalis orcadensis)

Found only on the Orkney Isles of Scotland, the Orkney vole is a true British endemic species. However, it wasn’t always found here and is thought to have arrived from mainland Europe around 5000 years ago when farmers arrived here from Belgium. This species can be found in various habitat types on the islands, including marshes, heathlands, and grasslands where they feed on a herbivorous diet of grasses, sedge, seeds, and roots, among other plant materials. Because of this, the Orkney vole plays an important role as a seed disperser as well as being a prey species for many local animals, including mammals and birds of prey.

The Orkney vole is typically gray to brown in color and is around 10% larger than other species of voles. This size and molar gigantism is thought to be just one of the specialized adaptations that allow this species to thrive in the challenging conditions of the environment in which it lives.

Orkney voles breed rapidly, having several litters each year, which they protect in an underground burrow. This, coupled with their adaptations to the environment means that their populations here are considered to be stable. That said, disturbances to their habitat are known to cause a problem which are largely a result of climate change. But, since these islands have a very unique biodiversity, conservationists are keen to protect the area. This includes a program to remove invasive stoats from the island, which could predate endemic species to extinction. 

11. Skomer Vole (Clethrionomys glareolus skomerensis)

Found only on the island of Skomer off the coast of Wales, the Skomer vole is a subspecies of bank vole that is thought to have been introduced by humans sometime after the last glacial period. However, numbers aren’t enormous, with only around 20,000 individuals thought to be living here.

Skomer voles are small creatures that only grow to around 4.7 inches (12 cm) and primarily feed on plant matter but are also partial to insects when the opportunity presents itself. They will forage for food both day and night but have a very short lifespan of only around 18 months.

These small voles are just one of four small mammals that live on Skomer, but they’re largely undisturbed by humans. While the island does receive some visitors, it is largely uninhabited and benefits from the protection of being a national nature reserve, which is hugely advantageous to this species. However, reports suggest that the Skomer vole, particularly females and their young, often struggle to survive over winter owing to a lack of dense vegetation that provides them shelter and cover. 

One of the main problems for the Skomer vole is predation, most notably owls, which not only prey on the adult voles but will invade nests and take the young.

12. Lundy Cabbage Flea Beetle (Psylliodes luridipennis)

Finally, we’re going to meet one of the few insect species that are endemic to the British Isles; the Lundy cabbage flea beetle. These beetles have an incredibly limited range and are only found on Lundy Island which is situated in the Bristol Channel. Here, they are primarily found on grassy slopes, heathlands, and rocky cliffs, where they feed on the Lundy cabbage, which is also endemic to this island.

The small insects measure just 0.1 inches (3 mm) in length and have a metallic coloration in either green/blue or blue/black. Amazingly, and likely owing to their limited range, they were only recorded in the mid-1800s. Sadly, numbers regularly fluctuate according to the availability of food sources. So, if the Lundy cabbage population has a particularly bad year, this affects the population of beetles.

On the other hand, these beetles are known for their ability to control cabbage growth and can affect its distribution and abundance. This makes them essential within the ecosystem as they help to maintain this endemic plant but they’re also backed by protection since the island is considered to be a Marine Conservation Zone. What’s more, Lundy Island is owned by the National Trust which aims to create priority wildlife habitats.

Moreover, the very existence of the Lundy cabbage was recently threatened by the invasive growth of a rhododendron species. However, programs for the removal of this species have been executed in the hopes of creating new viable habitat for the cabbage and therefore, the beetles.

One of the most notable characteristics of the Lundy cabbage flea beetle is its ability to jump which is a result of its strong hind legs.