Many of our neighbours have installed solar panels on their roofs, much to the delight of the feral pigeon population, which roost and breed in the sheltered spaces underneath. Consequently the local population has boomed and we regularly have thirty or more in the garden. Initially they were ground feeders, picking up bread or seed from the lawn. But recently one or two have worked out how to balance on the sunflower seed feeders, which are really not designed for such large birds. This behaviour has rapidly been learnt by other pigeons in the flock - culture in action. No wonder they're so successful.