The real furn gully

There's a gully next to our house full of turns I clean them up every year so that they grow big and beautiful, this year I found what at first I thought was a birds nest , but to my surprise it start shaking and when I looked at it again it was closed, were the top had been open at first. I now believe it's not a bird nest, instead I believe it to be a fairy hut, please leave comment