I only bought this recently and it is a copy of a section of a beautiful window in the main house at the National Trust Tyntesfield estate near Bristol. The Trust sells this roundel as a pigeon in its shop, but the estate owners made their fortune exporting Peruvian guano and I am convinced that this is just one of three main types of guano producing bird. Its excrement was dug from beneath it and exported as fertiliser, making it one of the most valuable birds in the world. It still lives and breeds off the coast of Peru, but in much smaller numbers, oblivious to the importance of its place in history. It will always remain a strong symbol to me of the significance of past human interventions in landscapes and the ecosystem changes that ensued – and why environment is such an essential component of historical study.