Unusually for a book about nature, the species in question, in this lucid story of the relationship between birds and humans, is ours. Why catch six million ibises, attractive water birds with curved beaks, plunge them into vats of liquid resin, wrap them in bandages and bury them in vast cemeteries in Middle Egypt in 650 BC?

When There Were Birds explains that these ibises were offerings to Thoth, god of knowledge and wisdom.