Last updated: 09:49 AM ET, Wed November 23 2016

How Are Airports Preventing Bird Strikes?

Airlines & Airports Paul Thompson November 23, 2016

How Are Airports Preventing Bird Strikes?

PHOTO: Birds smashed in the nose of this Singapore Airlines plane in August 2015. (Photo via Twitter)

Everyone is familiar with US Airways flight 1549, the one that hit a flock of geese and was forced to ditch in the Hudson River, near Manhattan. But what people do not realize is planes hit birds dozens of times each and every day. Now that we’re in migration season, it’s a good time to look at some of the things airports do to make our flights safer by mitigating harm from birds as much as possible.

Airports have several options to try to keep birds away from the airfield. At Nashville International, fifteen propane tanks shoot gas out with a cannon-like but non-lethal effect to scare birds away. But even with these cannons, birds have hit 83 planes at the airport so far in 2016, and nearby residents have voiced displeasure over the cannon sounds.

A group called Bird Strike Committee USA is focused on finding ways to deter birds from wanting to reside around airports. In some places, airports are experimenting with planting grasses that geese do not like to eat. Other examples include removing ponds and fruit-bearing trees.

Salt Lake City has replaced grass with gravel between runways. Airfield grass can be a habitat for rodents and rabbits, which are an attractive meal for some large birds. Salt Lake has also introduced pigs into the wetlands near the airport, because the pigs will eat the eggs laid by California gulls that nest near there.

WATCH: TravelPulse Founder Mark Murphy Talks Bird Strikes on CBS News

Sometimes, natural predators are also introduced. Fort Meyers International has been using a Border Collie, who run into thick brush to scare away birds and other wildlife where the grass is too thick to drive through.

At 53 square miles, Denver International is the country’s largest airport, and gravel is not really an option.  Denver has even experimented with tracking birds on an avian radar, but hasn’t found a viable solution just yet, because current solutions can’t verify the birds’ altitude. Denver uses gunfire in the form of two different sounds that are meant to “harass and haze” birds. The airport also reduced habitat by spending approximately 11,000 hours each year mowing fields on airport property. The airport is also surrounded by farmland, which does attract many bird species.

Some airports including Seattle International set traps for birds on airport grounds, then relocate them to a suitable area after they are caught. Over 300 birds were caught in traps at Seattle’s airport in 2012.

Scientists at William and Mary University in Virginia have developed what is being called a Sonic Net. It is considered a humane solution, where “pink noise” sounds are played at a frequency that interferes with birds’ hearing. The disruption in turn renders them incapable of discerning sounds from their predators, so birds will avoid the area. The study said the Sonic Net resulted in an 82 percent reduction of birds in the area where it was tested.

READ MORE: Which Species Are Involved In the Most Bird Strikes?

Three-quarters of bird strike damage occurs on the wing or engines. Wing damage can result in the reduction of flight control, making the plane more difficult for the pilots to maneuver. Engine impacts can be even more dangerous, especially at low altitudes where most bird strikes occur. When an engine ingests birds, especially large birds of prey or waterfowl, it can damage or break the turbine blades, causing metal shrapnel to be sucked into the engine. Once this happens, it can cause a loss of thrust or disable the whole engine, as we saw in the US1549 incident.

The number of reported birdstrikes to all types of aircraft in the US is nearly 13,000 per year — a steep rise from the average 2,900 annually in the 1990s. It is plausible that the protection of certain species has allowed species to proliferate so much that they are now becoming a nuisance. A 2011 Boeing paper said that 90 percent of all US bird strikes occur from species which are protected under the Federal Migratory Bird Treaty Act.

Since the dawn of flight, birds have posed a danger to aircraft. After all, birds were there first. In fact, the Wright Brothers were the first to hit a bird with their plane, in 1905. According to the FAA, bird strikes cause an average of $600 million dollars per year to aircraft, and the Commercial Aviation Safety Team says over 200 people worldwide have been killed in bird strike events since 1988.