I like to think we run an open-door policy in our library at home in Norfolk. That is to say, on warm days in summer the door to the garden is actually open. Anyone’s welcome to come in for a browse. Last summer a stoat wandered in, peered dismissively at the modest shelf of my own titles, sniffed about under my desk and then ambled out. Most Julys the house ants – here long before us and so given due respect – pour out from alarming new holes in the floor, march along the tops of my editions of Gilbert White’s Natural History of Selborne, and shuffle in a lost and desultory way about the carpet, seeming uninterested in getting outdoors for their nuptial flights. But while I fret about the continuance of their ancient lineage, the culling is already under way. Next through the door come the bolder blackbirds and robins, hoovering the insects up in front of the shelves.