We have a pair of beautiful house martin building themselves a nest right on the top of our bathroom window. Its the second year for them but this year they have decided to start building onto an open window! Presumably they will build right upto the eaves of the cottage. They are really lovely and not at all affraid of us however, the mess they are making in building the nest is quite amazing not to mention the mess that will come into the bathroom once they are feeding!! If I now shut the window will they abondon the nest? I don't wont to do that. Any other suggestions please.