Tag Archives: Diversity


Unless you happen to live in, or visit Scotland, Wales, parts of Ireland or the Isle of Wight, it is highly improbable that you would even catch a glimpse of a creature that has been a resident of the United Kingdom for millennia.

When was the last time you saw one of these?

That creature is the Red Squirrel (Sciurus vulgaris) and has been native to these shores since the land bridge between Britain and Europe began to disappear following the last ice age, estimated to be around 10,000 years ago.

Although it has to be said that by the 18th century, the numbers of reds had declined almost to the point of extinction in Scotland, a decline that can largely be attributed to the need for timber, and the felling of large areas of woodland – by the start of the 20th century, there was a thriving population of reds across the whole country.

The increase is believed to be due to a drive in the latter half of the 19th century to replace the trees that had been lost, which then restored the natural habits of many creatures, including our friend, the red squirrel.

Unfortunately, as we moved through the 20th century, the two world wars, which resulted in further tree clearances, and outbreaks of two fatal diseases (for reds) – Coccidiosis and the Squirrelpox virus, meant that the numbers had plummeted to the level previously witnessed in Scotland, but this time the entire country had been affected.

Although a number of theories have been presented for the decimation of the reds population in Britain, a significant factor, and one which has been proven to have contributed greatly to their demise – is the introduction of a pair of North American grey squirrels in 1876, at Henbury Park, Cheshire, by a certain Mr. Brocklehurst.

The instant novelty appeal of these ‘new’ greys, led to further releases throughout England over the following fifty years, and had spread to Scotland by 1892, where breeding pairs were introduced to a number of sites, including Edinburgh Zoo.

The spread of the exotic newcomers was far greater than had been anticipated, and for a long time it was believed that the decidedly more aggressive nature of the larger greys, was responsible for the replacement of the native species, however, extensive research has shown this not to be the case.

There are a number of factors that are now known to be a contributing factor in the stark imbalance between the two species, one of which is the greys’ superior efficiency in digesting acorns and hazelnuts, which, unlike the reds, they are able to process even before they are fully ripe, so are able to gain the nutritional benefits far earlier in the season.

Greys are also known to ‘steal’ the nuts and seeds from the winter stores of the reds, which results in faster and greater weight gain and improved levels of successful breeding.

Reds are dependant on their body fat reserves to successfully breed and rear their young.

It has also been shown that within fifteen years of the appearence of greys in their natural habitats, the reds are unlikely to remain.

There are now approximately 161,000 red squirrels in Great Britain, with around 30,000 in England, 10,000 in Wales (although recent estimates are significantly lower), and a main population of 121,000 in Scotland. The population in England has a very fragmented distribution, occurring in isolated populations in the south of England, on the islands in Poole Harbour and the Isle of Wight, in the east, in Thetford Forest (although this population may already have disappeared) and across the north of England. The Welsh population is mostly confined to discreet woodland patches, predominately in large coniferous forest blocks such as the Clocaenog forest and on the Isle of Anglesey. A survey in Northern Ireland gave a figure of 10,000 across the province. SOURCE

Following a survey in 2014, it is estimated that there are upwards of 2,525,000 grey squirrels in the UK, and despite any number of measures in place to control those numbers, they are expected to increase year on year.