I put up a robin shelf several years ago and have had no activity at all. None of the birds including robins seem interested. Other birdhouses have been more successful.

Anyone have luck with a shelf. If so where did you locate it?

I have had a shelf up in an effort to give some persistent barn swallows an alternative to my porch. A finch used it one year, but it mostly remains empty. I think it depends on the direction that it faces. I find that birds are particular about that. For example, barn swallows insist on trying to nest on my porch on little tiny window toppers about 1 1/2" wide. My s-i-l next door has a porch with huge beams and they never attempt to nest there. I thought maybe because their porch faced northwest. I have no reason to believe this, just this small sampling of info. All my bluebird boxes face northeast and they get used every year. I personally think birds like HOSP will nest anywhere.......which probably accounts for their numbers. If you are going to offer small boxes, it is always best to discourage HOSP from using them. No need to help them out. They do fine on their own and can nest with or without a box. By giving them a place to nest, it simply increases the competition on the natives.