Fixing nestbox above concrete patio

I was given a nestbox for sparrows, the type with three separate compartments.

I am proposing to fix this on a NE facing wall of my house, high enough so that a cat cannot jump up to it - say, 11 feet off the ground.

At the bottom of the wall is a concrete patio and my question is, when the fledglings leave the nest, will they be OK with the drop down to such a hard surface?