Can anyone help? We made a nest box a couple of years ago and the very first year we had blue tits nest in there. We were so exited. Later in the year long after they had left we had a sneaky peak in the box to see a perfectly lined what looked like carpet throughout. We left it in there and the following year we had no residents. So this year we have seen lots of interest but still it appears no birds want to set up home there. Do you think this is because we have left the moss carpet inside and birds are leaving the nest as they think somebody already lives there? Should we remove all of this moss? Any advice would be much appreciated..