Honestly, I deal with this same issue because my bench sits under a tree. The outdoor bench I always recommend is one made from HDPE lumber — often called “poly lumber” or “recycled plastic.” This material is non-porous, so bird droppings stay on the surface instead of soaking in, and they wipe off with warm soapy water or a quick hose-down.
If you want an easy-clean outdoor bench, HDPE is the gold standard. An HDPE outdoor bench never needs sealing, doesn’t rot or fade, and resists the rough grain that traps droppings. My top picks in this category would be a Polywood Classic Bench or a Lifetime 60-inch recycled plastic bench. Both have smooth, open slats that make cleaning around them simple.
A close second is a powder-coated metal bench — aluminum or steel with a smooth, sealed finish. The powder coating creates a slick surface that resists staining, and there are far fewer pores than wood. Just stay away from heavily textured cast iron, unfinished teak, or intricate scrollwork. Those details may look nice, but they collect droppings and make scrubbing miserable.
For a low-maintenance garden bench, I also recommend choosing open-slat seating or a smooth contoured top rather than a solid rough wood slab. Fewer crevices means fewer places for mess to hide.
My cleaning routine is simple: I keep a spray bottle with water and a couple drops of dish soap by the patio. Fresh droppings usually wipe off in seconds. For dried droppings, I spray the area, wait two or three minutes, and hose it off. A mild outdoor cleaner or diluted vinegar works fine on both HDPE and powder-coated metal, and I avoid bleach so the finish lasts longer.
So my recommendation is: get an HDPE or recycled plastic bench if you want the easiest possible cleanup, or a smooth powder-coated metal bench if you prefer a more classic metal look. Either one turns a gross bird dropping cleanup into a 30-second job.