How is the grey squirrel better adapted to certain environments than the red squirrel?
It is more able to utilise food sources such as acorns which are too rich in tannin for the red squirrel. This has led it to become more widespread and so outcompete red squirrels from their natural habitat. The red squirrel has more specific habitat requirements so cannot compete with such intense competition, since the 2 species occupy similar ecological niches. Grey squirrels also harbour diseases which are harmful to the red squirrels, so capable of wiping out entire populations if the grey is not eradicated. It’s sad, but the only way to save the red squirrel seems to be carrying out massive grey squirrel culls.
