If they're the ones I'm thinking about, with the pieces of bamboo, holes drilled in wooden blocks, etc. I've seen those in Germany, Switzerland, and the US. C

If they're the ones I'm thinking about, with the pieces of bamboo, holes drilled in wooden blocks, etc. I've seen those in Germany, Switzerland, and the US. Can confirm that they work in Western Washington, but they're for solitary "digger bees", not your standard honey bee.