Dunnock is the proper name of the birds known as hedge (or tree) sparrows. They are smaller than house sparrows and live together in shrubs and bushes instead of on houses. Although they are fiction these stories are based on a real family. The author was able to watch them in a shrub that fortunately had no leaves. They seemed to speak very good English. The only thing they were unable to explain to one another was why the sky fell in the last story. They had never heard of a "tarpaulin"!