Nest boxes originally served a very different purpose! Clay ‘nesting pots’ were introduced to England by Dutch labourers working in the Fens. They hung these pots around farmyards as convenient nesting places with the aim of reducing the damage caused by birds nesting in roofs. They also provided a ready source of protein in the form of the eggs and fledglings and had a handy ‘robbery hole’ at the back for access.
British Trust for Ornithology, July E-news.