How did gray squirrels get to the UK? Surprisingly, these familiar bushy-tailed creatures are not native to British forests but were deliberately imported from North America starting in the 1890s. The first recorded introduction actually dates back to 1876 at Hanbury Park in Cheshire.
Today, we’re facing the consequences of these Victorian-era decisions. In fact, over 2.5 million gray squirrels now populate the UK, with approximately 2 million in England alone. Meanwhile, our native red squirrel population has dramatically declined to just 161,000 remaining in Britain, with 121,000 concentrated in Scotland. This drastic change can be traced back to when gray squirrels were introduced to the UK at roughly 30 different sites between 1876 and 1929. The 11th Duke of Bedford, Herbrand Russell, played a particularly significant role in their spread, releasing gray squirrels from his Woburn Park estate and other locations including Regent’s Park. Though many wonder why gray squirrels were introduced to the UK, the answer lies in the Victorian fascination with exotic wildlife.
In this article, we’ll explore the surprising Victorian story behind where gray squirrels came from and how human intervention—rather than natural adaptation—fueled their rapid takeover of the British countryside.
The First Gray Squirrels in the UK
Early introductions from North America
The journey of gray squirrels to British shores began during the Victorian era, a time when collecting exotic species was considered fashionable among the wealthy. These bushy-tailed rodents are native to the oak-hickory woodlands of eastern United States, where they co-exist with the American red squirrel.
Victorian collectors sought these creatures as novelties for their estates, often initially keeping them as pets before eventually releasing them into the wild. Subsequently, what started as isolated introductions eventually became numerous deliberate releases across the country, forever changing Britain’s wildlife landscape.
When were gray squirrels introduced to the UK?
While unverified records suggest gray squirrels may have been present in Britain as early as 1828 in north Wales, the first documented introduction occurred in 1876. This landmark event happened when Victorian banker Thomas V. Brocklehurst released a pair of gray squirrels at Henbury Park near Macclesfield in Cheshire, following a business trip to America.
The period between 1902 and 1929 saw what historian Christopher Lever described as “a veritable wave of introductions” across numerous locations. Among the most significant releases were:
- 1890: Ten squirrels imported from New Jersey released at Woburn Park in Bedfordshire
- 1902: One hundred squirrels released in Richmond Park, Surrey
- 1905-1907: Ninety-one squirrels released in Regent’s Park, London
Interestingly, research has shown that large populations weren’t necessary for establishing colonies. A 2010 study found that over 70% of successful gray squirrel introductions arose from fewer than 10 animals.
Why were gray squirrels introduced to the UK?
The Victorian fascination with exotic wildlife provides the primary explanation for these introductions. During the 18th and 19th centuries, British travelers developed a passion for collecting souvenirs from their journeys abroad. Beyond art and antiques, plant and animal specimens became highly prized possessions.
Gray squirrels were specifically introduced as “ornamental species” to populate the grounds of stately homes. Estate owners viewed these exotic creatures as an interesting addition to their local wildlife displays, alongside other collected flora and fauna.
Furthermore, at the time of these introductions, nobody understood the potential ecological consequences. The Victorians had no knowledge that gray squirrels would thrive so successfully in British conditions or that they would pose a significant threat to the native red squirrel population. These charming imports were simply viewed as novel curiosities that would enhance the esthetic appeal of aristocratic estates.
The Role of Herbrand Russell and Other Victorians
Who introduced gray squirrels to the UK?
Among the Victorian aristocrats who shaped Britain’s wildlife, none played a more pivotal role in gray squirrel introduction than Herbrand Russell. The 11th Duke of Bedford, a noted naturalist and president of the Zoological Society of London (1899-1936), is widely considered “the chief importer of the invasive gray squirrel species to Britain”.
Although Thomas Brocklehurst made the first verified introduction in 1876, Russell’s actions proved far more consequential. Records indicate that between 1876 and 1929, gray squirrels were imported from the USA and released in approximately thirty different locations across Britain. Russell’s introductions, however, created the foundation for today’s widespread populations.
Woburn Park and the London epidemic
In 1890, Russell imported ten gray squirrels from New Jersey and released them at his estate, Woburn Park in Bedfordshire. These squirrels bred so prolifically that their offspring were subsequently captured and released elsewhere.
Consequently, the Duke introduced substantial populations into Regent’s Park in London, likely creating what researchers now term “the London epidemic of grays”. Additionally, he established populations in Richmond Park in Surrey. As Dr. Lisa Signorile, who studied the spread of gray squirrels in Britain, noted: “It was a time when we didn’t know invasive species could cause so much damage”.
Gifting squirrels to friends and estates
Perhaps most significantly, Russell didn’t merely establish populations on his own properties. Instead, he “gifted many gray squirrels around the UK from his home at Woburn Park”. He distributed pairs and groups of squirrels to friends and acquaintances throughout the country, encouraging them to release these animals onto their own estates.
This practice of aristocratic sharing explains why genetic research has identified “human-assisted long-distance jumps” in gray squirrel distribution rather than simple natural expansion. Indeed, Dr. Signorile identified Russell as “one of the worst offenders at spreading gray squirrels”, despite his otherwise positive reputation for animal conservation projects.
The Duke’s actions exemplify the Victorian era’s problematic relationship with exotic species – bringing back animals from around the world without understanding their potential ecological impact.
What DNA Tells Us About Their Spread
Recent genetic research has completely changed our understanding of gray squirrel expansion across the UK. Previous assumptions about their rapid conquest are now being challenged by fascinating DNA evidence.
Debunking the ‘super squirrel’ myth
For decades, scientists believed that gray squirrels swept across Britain because different populations interbred to create a “super-squirrel” with superior adaptive abilities. Nevertheless, this theory has been thoroughly debunked. Dr. Lisa Signorile from Imperial College London compiled a DNA database of nearly 1,500 gray squirrels in the UK and Italy, revealing that different squirrel populations remained genetically distinct. This genetic separation proves they didn’t engage in significant interbreeding as previously thought.
Genetic differences between populations
The genetic makeup of UK gray squirrels forms what researchers describe as a “mosaic” pattern, with each population reflecting the genetic characteristics of historic introductions. First, the genetic diversity of each examined population was lower than both US populations and historical UK populations. Second, migration rates from Woburn averaged between 0.028 and 0.097, showing limited genetic exchange even between nearby locations. Coupled with this, researchers found clear signs of inbreeding and small effective population sizes. Similarly, the Irish population has a considerably lower effective population size compared to British counterparts.
Evidence of human-assisted long-distance jumps
Perhaps most revealing, DNA profiling shows many recently established squirrel populations have relatives living surprisingly far away. For instance, gray squirrels in Aberdeen were most closely related to populations around the New Forest in Hampshire. Given the distance, only human intervention could explain such connections. A remarkable example occurred in 2010 when a squirrel captured on the Isle of Skye was genetically traced to Glasgow, confirming reports it had stowed away under a car bonnet. As Dr. Signorile concluded, “Gray squirrels are not as crazy invaders as we think – their spread is far more our own fault”.
The Impact on Red Squirrels and Native Wildlife
The ecological consequences of the Victorian gray squirrel introductions continue to unfold across British landscapes today, with native wildlife paying a heavy price for this historical decision.
Gray squirrel UK population vs red squirrels
First and foremost, the numbers tell a stark story of displacement. Currently, at least 2.7 million gray squirrels populate the UK, vastly outnumbering the declining native red squirrel population, which has dwindled to approximately 287,000 individuals. Of these remaining red squirrels, about 75% reside in Scotland, with England and Wales now classifying the species as endangered.
This dramatic shift represents a catastrophic decline from the historic red squirrel population of around 3.5 million before the gray squirrel introduction. In certain areas, once gray squirrels move in, red squirrels typically disappear within just 15 years.
Squirrel pox and competition for resources
The decline stems primarily from two factors. Notably, gray squirrels carry the squirrelpox virus without suffering ill effects, yet the disease proves almost invariably fatal to red squirrels within approximately two weeks. Upon infection, red squirrels develop debilitating scabs and sores around their eyes, nose, mouth, and other body parts, ultimately dying from starvation or dehydration.
Equally important, grays outcompete reds for food and habitat. Unlike red squirrels, gray squirrels can digest unripened acorns containing high tannin levels, allowing them to consume this important food source earlier in the year. Their larger size (550-650g compared to the red’s 270-300g) also requires more daily energy, putting additional pressure on shared resources.
Control efforts: culling, trapping, and pine martens
As a consequence, conservation efforts now focus on targeted gray squirrel management. In designated protection areas, control methods include trapping and humane dispatch. Under UK law, releasing captured gray squirrels back into the wild is illegal.
Interestingly, recent research offers hope through an unexpected ally: the pine marten. Studies in Ireland and Scotland suggest that increasing pine marten populations correlate with declining gray squirrel numbers and recovering red squirrel populations. This natural predator appears to impact grays more severely than reds, potentially offering a biological control method alongside human intervention.
The Victorian Legacy Continues
Looking back at this surprising Victorian story, we see how profoundly a seemingly innocent fascination with exotic wildlife transformed Britain’s ecological landscape. Though initially introduced as novelties for aristocratic estates, gray squirrels now dominate woodlands throughout the UK. The actions of Herbrand Russell and other Victorian collectors, albeit well-intentioned, created consequences that persist over a century later.
DNA evidence certainly challenges earlier theories about gray squirrel spread, revealing human intervention rather than natural migration as the primary factor behind their expansion. This genetic detective work confirms what many conservationists suspected – people transported these animals across great distances, establishing new populations far from their original release sites.
Red squirrels, unfortunately, continue to bear the brunt of these historical decisions. Their dramatic population decline stems directly from competition with grays and the devastating squirrelpox virus. Without significant intervention, our native red squirrels face an uncertain future in most of Britain.
Nonetheless, hope exists through targeted conservation efforts and the unexpected assistance from pine martens. These natural predators might help restore some balance to British woodlands, potentially allowing red squirrels to reclaim territories lost to their gray counterparts.
The story of gray squirrels in Britain thus serves as a powerful reminder about unintended consequences. What began as Victorian curiosity ultimately reshaped entire ecosystems. Their legacy teaches us valuable lessons about wildlife management and the careful consideration needed before introducing non-native species to new environments.
