What is the author's style in Birds, Beasts, and Relatives by Gerald Durrell?

The book is divided into three parts, titled "Perama," "Kontokali," and "Criseda." There is no explanation of these terms. Each of the parts is divided into additional chapters. Parts one and three have three chapters and part two has five. In part two, four of the chapters are numbered but there is also a chapter that is not numbered, but is named "Interlude for Spirits." This is the only chapter that is not set on Corfu and, falling in the middle of the book as it does, it seems to be a play on words. The "interlude" is an apparent reference to a break, as would be the case if this were a play. An intermission would typically include an opportunity for refreshment, but the "spirits" in this case are ghosts rather than refreshment.