TPS Bird Proofing

Birds create four distinct risks on a commercial building. Droppings are acidic and corrode paintwork, cladding, roofing and metalwork. Wet droppings on entrances, walkways and fire escapes are a serious slip hazard. Nesting material blocks gutters, downpipes and roof drains, which pushes water into the building. And droppings and nesting debris carry bacteria, fungal spores and parasites, which becomes a health issue where they are disturbed or where they sit near air intakes. The air intake problem is the one most often missed. Bird fouling near an HVAC intake draws contaminated material into the building’s air supply, which turns a roof problem into an indoor air quality problem. There is a duty angle too. Under health and safety law a business that manages or controls a workplace has to keep it without risks so far as is reasonably practicable, and a fouled entrance or walkway is a slip hazard you know about. The damage compounds quietly. Droppings left on a coated surface keep working on it, and a facade or roof that could have been cleaned becomes a repainting or replacement job.

Physical exclusion works best and is the only approach that reliably lasts. The main options are netting across recesses, voids and under canopies, stainless steel spikes on ledges and parapets, post and wire systems on narrow ledges and signage, and sealing or meshing the actual access points into roof voids and plant areas. Netting is the most effective where you need to exclude birds from a whole volume such as a loading canopy, an atrium void or a plant deck. Spikes and wire suit linear perching surfaces: ledges, sills, parapets, beams and signage. Sealing entry points is the one that gets skipped and the one that matters most. If birds can get into a roof void or a plant room, no amount of surface deterrent on the outside will fix it. Deterrents that rely on discomfort, startling or sticky substances tend to disappoint. Birds habituate quickly to visual and sonic deterrents, and gel-based products attract criticism on animal welfare grounds because small birds can become coated in them. For a building where reputation matters, exclusion is both the more effective and the safer choice.

Bird proofing is quoted per job after a site inspection, and the cost is driven mostly by access and by the area to be protected. The three variables are the method, the linear metres or square metres involved, and how hard the location is to reach. Spikes on an accessible parapet are inexpensive. Netting a multi-storey atrium void requiring rope access is not. Access usually costs more than materials on a commercial building. Getting a team safely to a facade or roof edge, with the rope access or platform and the safety systems that go with it, is the bulk of the price. Expect the quote to include cleaning and decontamination of the affected area before installation. Fitting exclusion over accumulated droppings and nesting material traps the problem rather than solving it, and the clean-up is a specialist job with its own safety requirements. Weigh it against what the birds are costing. Facade repainting, gutter and water damage repair, a slip claim or a tenant complaint all run well ahead of a one-off exclusion installation, and good exclusion lasts years.

Physical exclusion such as netting, spikes and sealing is both humane and legal, and it is the method the SPCA supports because it prevents birds using a space without harming them. The legal position on anything beyond exclusion depends entirely on the species, and that is where building owners get caught out. Under the Wildlife Act 1953 all birds are protected unless specifically listed as unprotected. Feral pigeons, house sparrows, starlings, mynas, southern black-backed gulls and spur-winged plovers are unprotected. Almost everything else is protected, including red-billed and black-billed gulls, both of which commonly nest on commercial rooftops in New Zealand. Interfering with a protected species can bring serious penalties. Timing is the critical practical point. Once protected birds are nesting they cannot be moved, so the work has to happen before the breeding season starts. The Department of Conservation advises building owners to check roofs and gutters every two or three days in the lead-up to breeding season and remove anything usable as nesting material, and to install deterrents early. Unprotected status is not a licence for harsh methods either. The Animal Welfare Act still applies, with substantial penalties for a company that ill-treats an animal. For a building owner, exclusion installed at the right time of year avoids every one of these problems.

Birds come back because most DIY deterrents target the bird rather than the reason the bird is there. Plastic owls, reflective tape, spinning devices and sonic units all rely on frightening birds, and birds habituate to anything that does not actually harm them, usually within weeks. Meanwhile the ledge, the food source and the entry point are all still available. What works long-term is removing the opportunity rather than scaring the occupant. That means physically excluding birds from the surfaces they perch and nest on, sealing the ways into roof voids and plant spaces, and dealing with what attracts them in the first place. The attraction side is usually food and water. Unsecured bins, food waste around loading docks and outdoor dining areas, standing water on flat roofs and in blocked gutters, and people feeding birds near the entrance. Fix those and the pressure on the building drops substantially. The other reason DIY fails is partial coverage. Birds move to the next ledge along. Exclusion has to cover the whole area they are using, which is why a proper site survey is worth more than a box of spikes.

Bird netting at height is installed by height access specialists rather than general pest controllers, because the work is rope access or elevated platform work on a facade, and it carries all the risk and compliance that goes with working at height. The credential to ask for is rope access certification and documented working at height systems. In New Zealand the relevant industry body is IRAANZ, the Industrial Rope Access Association of New Zealand. Certified membership tells you the operator works to recognised rope access standards rather than improvising. TPS is a certified member. There is a second competency involved, which is knowing bird behaviour well enough to design the exclusion properly. Netting installed with the wrong tension, the wrong mesh size, or gaps at the edges will let birds in and then trap them, which is both a welfare problem and a reputational one. Ask to see the method statement, the access plan, the public safety arrangements at street level, and what the warranty on the installation is. Good netting lasts many years. Poorly tensioned netting sags, gaps open up, and you pay twice.