Honestly, the trick is making the benches uncomfortable or inconvenient without turning them into an eyesore. Pigeons love flat, stable surfaces with a clear view, so the goal is to break that comfort.
Start with physical barriers. Anti-roosting spikes are the most reliable option for bench backs and armrests. Get the blunt, bird-safe type rather than sharp metal, because they work by removing landing space, not by hurting the birds. If the bench has flat top rails, install a sloped cover so pigeons cannot balance. Another effective method is bird wire or a taut fishing line run about two to three inches above the seating surface. Keep the wire tight and check it regularly, because a sagging line is useless.
Next, remove the reward. Pigeons usually gather where people eat, so sweep crumbs, seeds, and litter around the benches every day. If a nearby trash can is overflowing, that is an open buffet. Move the bin away or use one with a secure lid. You can also apply a non-toxic bird repellent gel to the spots they favor, but it gets messy and needs reapplication, so save it for hidden areas.
Reflective tape, fake owls, or shiny pinwheels might scare pigeons for a few days, but they adapt quickly, so do not rely on those alone. If you manage a larger area, overhead bird netting or angled panels above the benches work well. For a home bench, the cheapest quick fix is to make the spot temporarily unavailable. Drape a weighted tarp over it or place a few lightweight objects on the seat for a week. Pigeons are creatures of habit, and once the spot stops working, they move on. Combine two or three of these methods, stay consistent, and the pigeons will find somewhere else to loiter.