4184 x 2793 px | 35,4 x 23,6 cm | 13,9 x 9,3 inches | 300dpi
Data acquisizione:
29 maggio 2016
Altre informazioni:
Native to the eastern half of North America, grey squirrels were first introduced to Britain in the 1870s and are now widely distributed across the UK. With an estimated population of 2, 520, 000 across the UK, grey squirrels now heavily outweigh their red counterparts, of which, only around 10, 000 -15, 000 are thought to exist. Although originally imported as fashionable additions to estates, the grey squirrel is noted as the main threat to the survival of the native red population. Being larger than red squirrels and capable of storing up to four times more fat, grey squirrels necessarily stand a greater chance of surviving tough winter conditions. On top of this, competition is increased by their ability to produce more young and live at higher densities. However, rivalry between the species is not the only problem. Grey squirrels are carriers of the Squirrel pox virus, which the reds have no immunity to. It needs only one grey squirrel to introduce the virus to a local population of red squirrels for the virus to take a hold and spread throughout the entire group, with devastating effects. Where a grey squirrel has introduced Squirrel pox, population decline amongst red squirrels is 17-25 times more rapid than through competition alone. Although the future of red squirrels is uncertain, there are still high numbers present in Scotland. Results also found that pox-carrying grey squirrels were on the decline.
