In January 2017, I was waiting in the terminal of an airport that will remain unnamed. While in this terminal - at which passengers walk into a breezeway separating the terminal from the cold northern winds outside - I noticed a small bird in this breezeway that looked as though it was loafing in the area and enjoying the wind break it had found. I then watched as this bird continued to wait in this area until an airport employee walked past and opened the door so that they could enter the terminal. When the door was opened, the bird, which turned out to be a house sparrow (Passer domesticus), seized the opportunity to enter the terminal too, where it then began feeding on the crumbs of leftover food from waiting passengers and generally made itself known through making noise and flying through the terminal rooms and halls.
In the world of airports and aircraft, birds are a constant sight. While birds are a well-known issue in Active Operating Areas (AOAs) of an airfield, they can be just as much of an issue for the people working indoors (i.e. Airport terminals and Hangers). Some species, most notably house sparrows, European starlings (Sturnus vulgaris) and rock doves -AKA Pigeons- (Columba livia) are notorious for being able to find ways to enter a structure and set up house within it. With that homemaking ability also comes a cost to the humans who built and utilize that structure. That cost usually comes in the form of the droppings that the birds leave behind. These droppings can fall onto people and objects below and manifest themselves into a larger issue than the birds themselves. These droppings not only create a mess that must be constantly cleaned up; but can also act as a vector for many diseases, such as Salmonellosis (Salmonella poisoning), Histoplasmosis and E. Coli. In addition to the deterioration of the sanitary levels of the immediate area, these diseases add a hazardous and potentially deadly variable to the equation. These diseases can be transferred to humans, especially in crowded areas, through the disturbance of dried fecal material, which then can become airborne and be inhaled by nearby humans.
The first question that must be answered is “how are they getting in?”. That answer potentially lies in many forms, but the most obvious one to start with is the front door. Whether this is the large overhead door on a hanger, or a single “man door” separating an airport terminal from the aircraft apron outside. Birds have both the ability and the reputation to use these doors to enter a structure just like you or me. While it will certainly help to try and keep these doors closed as much as possible, sooner or later they will be opened, and even if that is just to let a person inside the terminal from the ramp, House Sparrows can easily take this opportunity to enter the building and the problems can only rise from there. For instances like these, one possible solution may be to try and limit the birds’ willingness to be nearby a door when it is open, and to do this, it may be possible to dissuade individuals to loaf nearby through the removal of perching areas where they birds can sit and wait right opportunity. In places where the perch site cannot be physically removed, it may be possible to modify that site so as so birds will avoid its use. This can be achieved several ways, but the easiest is to install exclusion devices. There are two common types of exclusion devices. Physical barriers can be as simple as multiple plastic or metal sticks emanating from a single base (lengths can vary but are generally about 6 inches in length) that make it difficult for a bird to comfortably land and perch; or a large scale as exclusion netting, eliminating access to an entire overhang or area. Liquid/gel applicants on the other hand, are substances that can be applied onto these same sites (or sites where physical barriers are not wanted to be visible) and leave a sticky coating on the surface that makes birds uncomfortable and unwilling to linger there. Another gel product that has come onto the market is known as Optical Gel, these small gelatin discs (which look like a cluster of corn kernels), offer a green, environmentally friendly alternative to bird abatement. Between containing materials that give off offensive odors to birds (but pleasant to humans), and emitting UV rays that look like flames to birds (there is no actual fire/flames), it persuades unwanted avian guests from loafing in areas where these discs are utilized. A factor that must be taken into consideration when using any liquid/gel application is its exposure to the environment. These substances have the potential to degrade overtime and will need to be reapplied. Other options could be more subtle in their approach, such as programing electronic sliding doors to open and subsequently close faster than standard programing to reduce the amount of opportunity a bird (or birds) have to enter a structure. In areas with multiple doors in a breezeway, such as at airports in colder climates, the timing of those doors can also be manipulated to disallow bird egress.
In addition to the door, if birds and/or bird sign (droppings or feathers) are found within a structure, precautions should be taken to make sure that any other potential avenue for entry is closed, such as holes or gaps in the walls or roof that may allow a bird to fit and make its way into a building. These openings can be as small as 1 inch, in which species can gain access into a building, or find a cavity to establish a nesting site.
New technology developments are now available to deter birds from loafing in unwanted areas. Sonic speakers can be generalized as a specialized audio speaker system that is used to emit bird distress and predatory sounds to stress unwanted visitors enough to the point where they vacate the area. In the short term, these products can be effective, although birds have been known to become conditioned and acclimated to the speakers to the point where they ignore them altogether and care must be taken to not allow this to occur. Through the moving of the sound system to new areas, as well as randomizing the time between calling sequences, managers can keep the birds on their toes so to speak, and not allow birds to become accustomed to the speakers. Another product type on the market allows for the blanketing of a large area to make birds uncomfortable in the area. This product is known as a Hazer, also known as a fogger. Hazers use a fan and sprayer to broadcast a chemical that is unpleasant, yet unharmful to unwanted avian guests and prompts birds to vacate the area that has been treated. These types of products are specialized to affect only avian species and not humans.
In some environments and situations where public perspective may play an important part in the approach to dissuading birds, a subtler approach can be to passively deter birds from congregating in an area. These areas could include open ceilings with exposed I-beams or other possible perches, such as underneath overpasses for walkways or roadways that allow for perching habitat. Places such as these do not require speakers or bird spikes, as other materials, such as netting can be installed to cover a larger swath of area, blocking the general area from bird access rather than only on specific perching sites.
Should the birds be successful in entering the structure, staff can utilize traps to remove the birds. These traps can be as rudimentary as a butterfly net and a lucky arm, or as complex as funnel, aka confusion traps which utilize a narrowing funnel like passageway, with the narrow end in the trap. These traps are baited with food, and the birds enter the larger outside portion of the trap and follow the food into the trap, all the while the funnel is forcing their heads lower until they enter the main chamber of the trap, where the birds regain their natural upright stance. The confusion part of the traps name comes from how the birds are unable to escape the trap, as they will not naturally lower their heads to leave via the funnel they entered from.
The funnels take advantage of this natural unwillingness to “duck” and allows for a trap that is easy to move and manage and can be quickly placed and baited in a likely trapping area. A quick note about these traps, is to have a trap where the funnels are built separate from the main trap structure, and hanging the funnels by hog rings, allowing for not only a funnel, but also a flipping door reminiscent of a “doggy door”. The purpose of this swinging door is not for the entry of the birds, but so they funnels can be swung up and attached via clips or zip ties to the roof, allowing for unhindered access to the baited trap, which in turn makes the birds more comfortable with the entire setup. Prior to setting any trap, a few days should be taken to “pre-bait”/feed the birds. Pre-baiting should take steps in attracting birds to a specialized location (area outside of public view), then baiting within the trap placed in the location, but an exit door left open. This allows the birds to become acclimated to entering and exiting the trap. Then finally the trap door is closed, and birds can be captured and removed. Pre-baiting prior to attempted trapping can increase catch success, especially with birds that may be “trap-shy”.
In the end, unfortunately, no matter the precautions that an airport is willing to undergo, unwanted avian guests will almost always be able to find a way into places that they believe they can find either food or shelter and especially both. The best practice to minimize their impact on the day-to-day traffic within a terminal is to provide routine monitoring support in the form of trained staff. Staff should monitor structures for activity and convey information to proper channels (wildlife staff and/or maintenance) of their presence and during which time the birds can safely and discretely be removed the building.
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