I'm sorry I'm not a bird expert, but I am desperate for some advice! For years now we have had a pair of swallows nesting in our garage (I heard a radio broadcast that suggested these would be the same birds returning). We have now got planning permission to raise the roof of this building. So, the actual remnants of the nest would be moved, the roof might be off as they return and obviously everything would look different once it is finished. I don't know the exact time of year they come, but the builders are due to start about now. I would be heart broken if this stops them coming back, or worse, I haven't seen them yet but don't know if they use last years nest, which will obviously be moved. Any advice on how to do this in the best way would be much appreciated.