Our kitchen has a little separated space where it's a bit colder and there we keep some food that doesn't need to stay in the fridge. This room has also a little window which was always opened for ventilation. The pigeons found it to be safe enough so they used to make nest there. It was almost like to have a pet, though we couldn't touch them, nor we wanted to do that, they would probably be scared, but we shared the same roof 🙂 And it was nice to watch how they grow and then fly away.
Now we installed the new central heating system in the apartment so I don't think the pigeons will come again.