How can we stop birds from stealing from coming into out loft?

There is a small hole underneath the tiles, which we are getting fixed soon, but how can we deter them from coming in the hole in the meantime. We cannot do anything from the outside as we do not have a long enough ladder, but we have blocked the hole with chicken wire from the inside. There is still a gap between ther tiles and the joists. Please help - they are stealing our loft insulation to build their nests!!!