Some years ago, when Morton Buildings put up a storage building on farms, etc. they would install "bird rods." These rods were a section of aluminum tubing with a wick protruding the length of the rod. They were treated with a substance and when a bird landed on the rod, the substance would be absorbed thru their feet.
With bird rods in the building, within a few days not a single bird would enter/roost in the building even with the huge sliding doors open for extended periods of times .. like weeks on end in the summer.
NO idea if Morton Buildings still has "bird rods" as whatever was in the rods to keep the birds out was probably to effective and the government banned it ..... like they did with DDT. A call to a Morton Building retailer would tell you.