Last year a pair of goldfinches nested in a standard growing in the nursery. Luckily, as Bert had grown it from a slip of privet that our old dog Danny had pulled out of a hedge, it was definitely not for sale. Danny had this crazy habit when travelling in the van where he'd snatch and bite at bits of hedges in overgrown lanes. They seemed to rile him.
So Bert grew this bit of privet into a very nice standard. It's about eight years old now and he's been offered good money for it on many occasions. But as I said it's not for sale. We don't have Danny any more but we do have his tree and it will be planted at our new house. Old Danny is already planted there under a mountain ash if I recall correctly.
Last year's goldfinches raised the young ones successfully but they're not the last birds to fail to make a distinction between nursery stock and other nest-building options. This year we have wrens nesting within a group of six larches in the polytunnel. Those larches should be stood outside but they cannot be moved or sold until the wrens are done with them.