ALFRED HITCHCOCK KNEW 40 years ago how scary swarms of birds can be. With bird populations often exceeding 10,000, there is no question that landfill managers need to know which methods effectively control the population.
It is important to adopt bird control plans to protect human health and to prevent damage to airplanes caused by bird strikes. Birds have been identified by major health agencies worldwide as carriers of disease, such as the avian flu, which is currently a significant problem in the Far East. When birds are infected, they can live for months, which allows bugs or parasites to transfer disease to other birds, animals or humans. Landfills provide a place for birds to congregate, feast and rest. Thus, landfills, provide ample opportunity for disease to pass readily from one infected bird to another.
There also is a high cost of having birds and planes in the same airspace. An estimated $5 billion worth of damage — and loss of life — is caused yearly by birds striking airplanes. This is why it is especially important to reduce bird populations around landfills near airports. If a landfill near an airport wants to seek an expansion permit, the Federal Aviation Administration (FAA) may object unless a bird control plan is in place or enacted.
There are many bird-control systems available for landfills, so it can be difficult to determine which ones will work at a particular site. For a bird control system to work: landfill management must be active in employing bird control techniques; the techniques must be varied to prevent habituation; and techniques must complement and reinforce the other methods being used. Many systems may work initially, but birds get acclimated to techniques when only one process is used.
The Crow Wing County landfill in Brainard, Minn., created a bird control plan using several techniques. The site has been under scrutiny for two years because the nearby local airport wanted to lengthen its runway. Consequently, landfill management had to control the bird population feeding at its site. The landfill originally had about 10,000 gulls, a number of crows and a few starlings, but management used three processes to get the population down to about 100 to 200 birds. Each technique they used reinforced the other, forcing the birds to find another food source.
The first priority was to make the food source inedible. For that, the landfill mixes methylanthranilate (MA) with ProGuard SB, a slurry-based alternative daily cover material, and sprays the landfill's open working face with it. In the spring, the landfill uses higher concentrations of the MA material in the daily cover batch to prevent the birds from feeding at the site at the beginning of the bird's mating season.
Landfill management also sprays the slurry in the birds' loafing areas, where they rest before taking flight to acquire more food.
The landfill has also been permitted to kill a set number of birds per year, so four operators have been trained and certified to shoot gulls and crows. The birds' distress is re-enforced with pyrotechnics, which are blank shells that launch a device that explodes in the air to create noise.
One landfill's bird control technique may not work for another. The biggest factor affecting the aggressiveness of a bird problem is the proximity of the roosting areas to the landfill. For example, a transfer station that is within 13 kilometers of birds' roosting area is likely to have a much larger bird population that will rotate in and out of the food source site. So, what initially appears to be an ineffective bird control technique may work, but there are so many new birds arriving at the site, the control techniques may appear not to work. This is why multiple techniques are needed to effectively control the bird population.
Other bird-control techniques include complete enclosure, which is the preferred method in the United Kingdom (UK), although it is expensive. Some new portable netting system technologies have been developed, but few landfills, if any, use this method in the United States.
The Central Science Laboratory in the UK has conducted extensive research examining bird control techniques to evaluate effectiveness. The laboratory looked at bird populations before and after employment of the techniques and how long it took birds to habituate to the prevention methods. The systems studied, in order of effectiveness, include: netting systems, birds of prey (primarily falcons), pyrotechnics, distress calls, blank firing pistols, bird-scaring kites/balloons and other visual techniques, chemical methods (besides MA, which is not permitted in the UK), and automated sound generators, which did not work at all. All of the other systems studied worked to varying degrees of success.
The most important lesson of the study is to stay committed to ridding birds from landfills and do not use just one technology. It will take money to effectively control population — it is not a one-hit fight. Birds will flock back if the defenses are not maintained.
— Milton Knight
New Waste Concepts