It is true that squirrels, both grey and red ones, are opportunistic feeders, and, if they come across an unattended nest, they might take an egg. But the point is, they are not predators, they will not deliberately seek out eggs, they do not hunt the chicks, and what they do is statistically negligible.

Actually, the presence of grey squirrels can assist birds. When grey squirrels strip bark (which does not, by the way, happen very often – see the section on damage to forestry), it encourages fungus growth and insects – food for birds.

Cats, most of whom are non-native to the UK, kill millions of birds each year, yet there is rightly so no demand for them to be culled, as is the case with grey squirrels.

An interesting food for thought, and something that scientists do not yet seem to have analysed, is the number of birds grey squirrels save each year, due to their 'alarm calls', which they employ when predators are in the vicinity. Wildlife learn each other's 'alarm calls'. A mutual benefit.