Having said that, loud ultrasound is annoying into the birds and discourages nesting and roosting. Some units impact birds around a location of about an acre (4000 square meters). The better part is this fowl netting is barely visible from the ground, so it would not produce an eyesore. Timeframe– https://zed-directory.com/listings12985571/installing-a-pigeon-repellent-in-arar-no-further-a-mystery