Wildlife and Airplanes: How Airports Ensure Safety in the Skies
The Incredible Danger of Wildlife
Wildlife is everywhere - it’s unavoidable. You can’t escape it, no matter how hard you try. In most situations, wildlife is at most a nuisance - sure, raccoons can make a mess in the trash bin, and squirrels can cause a headache in your attic, but it’s not generally the end of the world. It’s a bit different when it comes to aviation - wildlife, particularly birds, is an incredible, existential threat to aircraft.
Wildlife collisions with aircraft cost U.S. civil and military aviation approximately $1 billion annually, according to the USDA. It’s not something that’s going away either - the reporting of wildlife strikes with civil aircraft increased by 90% from 7,600 strikes in 2008 to 14,500 strikes in 2017. The greatest danger to an aircraft is presented by birds. If ingested into an engine, they can cause serious damage and even an engine failure. This exact scenario was the cause of the infamous US Airways Flight 1549 “Miracle” landing on the Hudson River, and, more recently, a FedEx 767 suffered a catastrophic engine failure after striking birds on takeoff from Newark.
Additionally, birds can cause significant, but generally not cataclysmic, damage to airframes and windshields.
Other animals can present problems as well - large mammals like white-tailed deer are somewhat frequently involved in aircraft collisions (about 1,210 documented incidents from 1990-2019). Other more isolated instances include a United 737 MAX striking a coyote on takeoff from Chicago in January, causing damage to the landing gear and necessitating a return to the airport.
MSP’s Unique Challenges
As I was researching this topic (for a school project, initially), I reached out to someone I know who works at the Minneapolis-Saint Paul International Airport’s operations team. He in turn put me in contact with a member of the airport’s wildlife management team. From this, I learned that MSP has a set of very unique challenges when it comes to contending with wildlife, and because of this, they have some extremely unusual ways of managing.
To understand the problems facing MSP when it comes to wildlife, you need to understand the airport’s geography. Though the airport is in a generally urban and suburban area, its southern border directly meets Fort Snelling State Park, which is just across the highway from 30L/30R. This area has a lot of water, including the Minnesota River, but also a number of smaller lakes among the dense forest. This means that it’s absolutely heaven for all sorts of birds, from the small Dark Eyed Junco to the large and majestic Bald Eagles and Sandhill crane. It’s unavoidable to either depart or arrive directly over the State Park, which means that it’s inevitable that there will be at least a few bird collisions annually, given how busy an airport it is. In 2022, there were at least 150 bird strikes involving aircraft departing or arriving in MSP’s airspace.
Another challenge of MSP’s location is the wetland/grassland area at the northern end of the airport. This area is well known to be home to the rare (and extremely beautiful) snowy owl. They are attracted to tundra-like, treeless terrain, which makes places like the flat areas at airports very nice habitats for them. The airfield is full of rats, voles and mice, so they like to stay in the immediate area to hunt. This poses a danger to aircraft, as the snowy owl is large enough to cause some fairly serious damage to jets. Unfortunately for the wildlife team at MSP, it’s not as simple as trapping them and moving them to a safer environment. Because they’re raptors, there’s a lot of legal restrictions on how to manage them. The US Department of Fish and Wildlife maintains an office on site, in part to deal with the owls, as only certain designated people are even allowed to trap them, much less move them.
It’s not easy to do that either - they’re extremely cautious birds, and as the USDA wildlife biologist at MSP put it, “I tell people it’s kind of like fishing. Sometimes they want to bite and sometimes they don’t … [snowies] are just a different kind of animal than what we typically are dealing with here.”
Managing Birds
Birds of prey are only part of the issue at airports. Crows, ravens, and egrets, among others, are all birds that could cause serious problems if they get into places they shouldn’t be. It’s not possible to trap them all, so airport have a few ways of keeping them at bay.
Who Let the Dogs Out? (the airport did): Dogs can be found in use at airports around the globe to drive away wildlife. They are let out onto various airport surfaces, including the ramp, runways, and taxiways to harass flocks of birds into fleeing the airfield. They’ll come back, so it’s not a permanent solution, but if they’re shooed enough times, maybe they’d find somewhere else to live.
Various Sound Methods: One of the most popular bird dispersal methods are guns filled with blank rounds, just to make a loud, unexpected sound that would distress the birds. This requires someone to physically go out and shoot in their general area (don’t worry, it doesn’t hurt them, as nothing is actually shot out of the gun). Some airports also set up small propane cannons at strategic points around the airfields that can be remotely triggered. There’s also bio-acoustic devices that broadcast distress calls, or the sounds made by predators, which also works at scaring the birds.
Visual Deterrents: Devices like lasers and predator effigies are employed to frighten birds. For example, green laser beams can effectively disperse birds, especially under low-light conditions. These techniques need to be used with extreme caution, as these visuals can be distracting for pilots, or create confusion.
Population Management: Some airports implement humane population control methods, such as avian birth control programs, to reduce bird numbers over time. These programs aim to decrease reproduction rates, leading to a gradual decline in local bird populations.
Exclusion Techniques: Physical barriers, such as bird netting and spikes, are used to prevent birds from accessing specific areas like hangars and terminals. Netting creates a barrier to deter nesting, while spikes discourage perching on structures.
Chemical Repellents: Airports apply non-toxic chemical repellents, such as methyl anthranilate and anthraquinone, to deter birds. These substances make treated areas unappealing for birds.
Falconry: Employing trained falcons or other birds of prey to patrol airport grounds leverages natural predator-prey relationships to deter smaller bird species (I suggest looking up falconry on YouTube - it’s extremely impressive).
Ultrasonic Deterrents: Deploying ultrasonic devices emits high-frequency sounds that are unpleasant to birds but largely inaudible to humans, encouraging them to avoid certain areas.
Cutting off Food: Some techniques can be used to make the area unattractive to birds by removing their food supply. Airports often cut the grass really short, so there’s not a ton of rats and mice living there. Pesticides also might be used to keep worms and other critters from thriving, so birds don’t have anything to sit around and eat there.
Communicating With Flight Crews: BIRDTAMs are often issued at US airports when birds are indicated on radar or visually, so pilots taxiing, taking off, and landing can be aware that there’s an increased likelihood of birdstrikes.
Assessing the Risk
Airports are required by ICAO and the FAA to conduct thorough wildlife risk assessments on the airport grounds and in the surrounding are. These assessments involve comprehensive evaluations of wildlife species present in and around airport environments, analyzing factors such as species behavior, population densities, and attractants like food sources or habitats that may draw wildlife to airport vicinities.
Sources & Further Reading
ABC News
United States Department of Agriculture Animal & Plant Health Inspection Service
United States Department of Agriculture Wildlife Service
SKYBrary
Aircraft Owners and Pilots Association (AOPA)
The Minnesota Star Tribune
KARE11 News
ICAO
Passarella & Associates, Inc.
APEX
