Until recently, squirrels in our back garden were a source of great amusuement as we fruitlessly devised Mensa-type tests to prevent them from stealing food put out for the birds.

However, their numbers this year have dwindled almost to the point of non-existence which I find very strange.

What is going on? Have they followed the Pied Piper to pastures new, or is there a more sinister reason for their non-appearance?

SHIRLEY NELDER Dene Road Headington Oxford