A bird (blue tit) is making a nest in the downpipe that takes our toilet waste. The pipe used to have a cap but it blew off during the winter. The nest is presumably quite near the top (where the pipe turns before dropping in a straight line) and the toilet outlet is quite a way down from that. Would you just ignore this? If it does fall it will be leaves and small twigs which won't block the pipe. I think that when it does eventually rain the bird might move on anyway as at the moment it has a nice dry home. Has anyone here seen this before?