However, loud ultrasound is annoying towards the birds and discourages nesting and roosting. Some units have an affect on birds about a region of about an acre (4000 square meters). Pigeon repellent gel can be a jelly-like material that is quite sticky and uncomfortable for pigeons. This gel can be https://zion1qzhp.ttblogs.com/11082165/installing-a-pigeon-repellent-in-arar-an-overview