Hi Sylvia. So do you have a large garden in the west of the UK, or a mountain garden? Or a large conifer tree where they breed? Or are the ravens a new arrival in your area now they are expanding their range eastwards after decades of persecution had pushed them out?
Maybe not so rare, but I have ravens in my garden!
Bats, it was two or three years before we knew we had a summer roosts in the eves of our house. The local Bat Group paid us a visit and identified the bats as common Pipistrelles. They explained about their decline and suggested ways we could help our bats. I planted to attract insects and we left 'bat friendly' spaces in the eves of the buildings we are renovating.
We were pleasantly surprised at how much wildlife was attracted by a small change in what was planted. For the past four years we have had Spotted flycatchers breeding in the garden. I wonder if this was down to the planting or luck? Either way they we feel privileged to have them.