How can we stop jackdaws ruining our russet crop | Notes and queries

The long-running series in which readers answer other readers’ questions on subjects ranging from trivial flights of fancy to profound scientific conceptsThis year we have had a big problem with jackdaws spoiling our apples: they have taken a peck from so much of our fruit that it has ruined a good crop of russets. We never used to have jackdaws round here, but they moved in a few years ago and are now a serious pest – they rival the magpies. Does anyone know why jackdaws arrived her