This specimen of Sciurus carolinensis (common name: eastern gray squirrel) was photographed in northern Italy, where he's considered an alien species.
It was widely introduced in Europe where it's considered one of the "100 of the World's Worst Invasive Alien Species" (a list written by ISSG, a group of the IUCN that studies only alien species).
In fact on my peninsula he's competing with the native red squirrel (Sciurus vulgaris) and the problems are many:
First of all, during the winter the red squirrels tend to reduce their activity a lot, especially on bad weather days where they can hide even for days inside their shelters.
For this reason they accumulate large stocks of seeds and dried fruit which are however taken away from the gray squirrel (up to 50% of the accumulated resources) which in winter remains much more active.
So many red squirrels die during the winter or they won't have the necessary energy for reproduction that will take place between February and March (then there is a second one between June and July).
First of all, during the winter the red squirrels tend to reduce their activity a lot, especially on bad weather days where they can hide even for days inside their shelters.
For this reason they accumulate large stocks of seeds and dried fruit which are however taken away from the gray squirrel (up to 50% of the accumulated resources) which in winter remains much more active.
So many red squirrels die during the winter or they won't have the necessary energy for reproduction that will take place between February and March (then there is a second one between June and July).
Another problem is that the gray squirrel is more voracious than the red one, and therefore the latter will struggle to find seeds, acorns and other dried fruit to feed on.
Furthermore, the gray squirrel, in addition to damaging the wooded areas, feeds on the eggs of birds and frogs, thus also endangering their survival.
Finally, the gray squirrel is the healthy carrier of a virus (Poxvirus) which, if transmitted to a red squirrel, would die within 1 or 2 weeks.
Furthermore, the gray squirrel, in addition to damaging the wooded areas, feeds on the eggs of birds and frogs, thus also endangering their survival.
Finally, the gray squirrel is the healthy carrier of a virus (Poxvirus) which, if transmitted to a red squirrel, would die within 1 or 2 weeks.
