I have strips of mahogany with 1.5" stainless nails speced an inch apart. I tape the mahogany strips to the spreaders. It works fine. When I first made up the bird deterrents, I put the nales about 2" apart and the birds simply put their feet between the nails. The only problem with making the spreaders and mask top "uinfriendly to birds" is that the birds land on the booms and dodger bow instead.