I have an open cage policy with my budgies 24/7. It's been working out well so far however there is a wooden windowsill they frequently perch on (shown in attached picture). While they are up there they will chew on the wood and poop, both of which is slowly damaging the paintwork.
Are there any ways I can prevent them from perching on the windowsill? I was thinking of laying a triangular piece of wood along the windowsill, creating a sloped surface, which may possibly make it awkward for them to land and deter them from doing so. Any ideas?