Swallows and plovers and herons, oh my! Surrounded by mangroves, salt marshes and wetlands—and directly in the path of the Mississippi and Atlantic Flyways—Florida’s Key West International Airport (EYW) is an attractive site for a wide range of wildlife, especially migratory birds flying south. Since birds and aircraft are a dangerous combination, EYW has a comprehensive and adaptive wildlife hazard management program to help ensure the safety of both aircraft passengers and local wildlife.
The airport has prioritized this effort since 2015 with a range of initiatives designed to reduce the bird population and shrink the number of wildlife strikes, while also protecting its environmentally sensitive habitat and following state and federal regulations.
Changes on the Fly
At the heart of the program is Mariben Andersen, associate vice president of environmental services at Michael Baker International, who also serves as the airport wildlife biologist for EYW. Andersen oversees the airport’s wildlife mitigation strategies, conducts inspections, and provides expert guidance and training to its internal wildlife management team, which is led by Deputy Director, Airport Airfield and Landside Operations, Cale Hartle.
 facts&figures
Project: Wildlife Hazard Management Location: Key West Int’l Airport, in FL Challenges: Several species of birds (egrets, swallows, plovers, herons, etc.); iguanas; turtles; marsh rabbits; snakes Primary Strategies: Daily inspections & wildlife logging; annual site visits by airport wildlife biologist; stormwater management to reduce standing water; iguana trapping; scare tactics; depredation (firearms); vegetation management, including mangrove trimming; larvicides & insecticides to reduce mosquito population; falconry Key Partners: Michael Baker Int’l; Jacobs Engineering Falconry Provider: Predator Bird Services Inc. Measurable Success: Documented reduction in birds observed at airport—in 2022, there were 1,277 fewer than the 7-year average from 2015-2023; in 2023, there were 291 fewer than the 5-year annual average Natural Anomalies: In Aug. 2021, 4,468 white ibis migrated to Key West, resulting in highest number of birds observed in single month at airport since 2015. In Sept. 2017, Hurricane Irma destroyed airfield vegetation, causing 400% reduction in bird population compared to 2016. |
Hartle, who collaborates closely with Andersen on the implementation and evolution of the wildlife management program, says that EYW’s unique location presents some special challenges. “Key West is an island, but if you look at our airport, we’re basically an island within an island,” he explains. “It’s the largest area of open space on this four-by-two-mile island, which unfortunately makes it a great place for wildlife.” In addition to birds, the airport is home to iguanas, turtles, marsh rabbits and snakes, which each pose a myriad of risks to aircraft operations.
One key component of the program is frequent inspections—three per day and two each night to monitor the airfield for wildlife. Reports and observations from the inspections are added to a comprehensive wildlife log that was started in 2015 to identify changing patterns and track program success. “If our staff notices an unusually high number of birds, they take immediate action to move them off the airfield,” says Hartle.
Continuous monitoring provides valuable monthly and yearly data the airport uses to fine-tune its efforts. That includes looking at seasonal variations and making real-time, data-driven decisions to adjust management efforts, such as increasing inspections in late summer and early fall during peak bird migration periods. “In July, August and September, we pay really close attention during the inspections, because barn swallows start migrating then and there are more birds at the airport,” Andersen explains. Historically, those are also the months with the highest level of strikes. In August 2021, for example, a record 4,468 white ibis migrated to Key West (100 times more than the usual amount). Based on data from 2015 to 2023, wildlife strikes range from zero to two during most months. However, incidents increase in August, which ranges from zero to 33 strikes, and September, which ranges from zero to 10. The majority of these strikes are barn swallows.
Mitigation efforts at the airport include mosquito control spraying, the use of larvicide and insecticide to kill insects, because they are attractive food for birds. Aggressive vegetation management, which includes mowing grass and trimming mangroves, is another key way EYW discourages birds from congregating on its land. As a last resort, it uses depredation (firearms) if noise makers such as bangers, screamers, rocket launchers, horns and hazing fail to scare away birds.
Variation is essential to keep the wildlife guessing. “The element of surprise is important,” Andersen says. “One time, they’ll use one banger; the next, they’ll use two bangers or three screamers. We don’t want the wildlife to habituate.” Birds even get used to the truck that staff members use for airfield inspections, so they change that often, too.
Introducing Predators
EYW has also used falconry since August 2021. The program is implemented in conjunction with Predator Bird Services Inc. and contracted through Jacobs Engineering and Michael Baker International. From April through December, specially trained Harris hawks are brought onto the airfield two to eight times per month to chase away or kill other birds. Handlers vary the timing of their four-hour shifts from sunrise to midday to sunset, again to keep the resident wildlife guessing.
“The falconry program has been incredibly effective,” Andersen reports. The Harris hawks, Lilith and Cheddar, establish the airport as their territory, sending a clear message to other wildlife that the area is controlled by a predator.
Although it can take anywhere from six to 12 months for predator birds to establish their territory, Andersen says EYW experienced a reduction in other birds by the second day of the program.
“The memo has been sent and the message has been received by the wildlife at the airport that this is Lilith or Cheddar’s territory,” she explains. “If you step within the boundary, you are going to get harassed, killed or eaten.”
Thanks to the hawks, bird sightings—including snowy egrets, cattle egrets, great egrets, great blue herons, tri-colored herons, white ibis, sandpipers, plovers, whimbrels and, as of late, ducks—have been significantly reduced.
“The falconry program has been incredible,” Hartle stresses. “And there’s nothing more exciting than sitting in a truck with a hawk and seeing it fly out to go do its job.”
Complying With the Regs
Andersen regularly conducts comprehensive training sessions for members of the airport’s wildlife group, which includes both airport staff and tenants. “We take a group approach to handling the wildlife threats we see on a daily basis,” says Hartle. “That includes our FBO, security personnel, operations staff, maintenance workers, even our landscapers. We go through our plan, and then we walk through what birds and other wildlife they can expect to see and what we need to do to make sure we mitigate as best as possible for the safety of everyone.”
The training also details steps required to comply with the airport’s depredation permit, which was obtained as a last-resort mitigation method in 2019. Andersen informs the team about adhering to federal and state regulations regarding protected species. Key West is a wildlife sanctuary, so birds like the Key West chicken, which likes to hang out at the airport, are protected. To help, EYW posts signs near the terminal to keep travelers from feeding them.
Like so many other aspects of airport operations, wildlife management requires paperwork. Andersen teaches staff and tenants how to properly document and comply with the FAA reporting system for wildlife strikes. “Even though we’re doing all this work to make sure we’re keeping wildlife off the airfield, there are going to be wildlife strikes. It’s just a part of aviation,” Hartle says. “When those do occur, Mariben [Andersen] does a very good job of training our team on the required steps. It’s a very in-depth training process that has created a lot of wildlife officers here who are very knowledgeable and very good at what they do.”
Unexpected Help
Being sensitive not to downplay the overwhelming negative effects of Hurricane Irma in September 2017, both Hartle and Andersen agree that the category 4 storm did Key West a big favor in terms of reducing the bird population by a whopping 400% compared to the previous year. The airport documented just 509 bird sightings in 2017.
Irma effectively removed half of the island’s vegetation and wildlife habitat, making it an unattractive stopping point for most migratory birds. “We saw a significant reduction in birds and wildlife at the airport after Hurricane Irma because it decimated all of the trees and the shrubs,” Andersen explains. “If there’s no place for them to hide, they’re not going to go to the airport, which speaks to why we need to have a very comprehensive vegetation management plan.”
Hartle says it’s unfortunate that vegetation around the airfield took the hit that it did, but it definitely helped deter wildlife.
Danger on the Ground
Not all of EYW’s wildlife hazards are feathered. Cold-blooded iguanas and turtles like to sit on taxiways and runways to soak up heat from the asphalt, especially during winters. Staff inspect the perimeter fence daily to look for any openings that animal intruders could squeeze through. The airport also began trapping iguanas in 2019.
Andersen says EYW’s diligence is paying off. “When I first started going to Key West seven or eight years ago, we used to see iguanas all the time. But because of the trapping program, I have not seen an iguana in the last three years,” she reports.
Staff also look for marsh rabbits, mice and rats, which serve as food for raptors as well as medium-sized mammals such as raccoons and opossums.
Step-by-Step Approach
The success of EYW’s wildlife hazard management program is measured through careful monitoring and data collection to identify patterns and changes over time. For instance, staff have documented a significant reduction in the number of birds at the airport. When the program began in 2015, they would observe as many as 50 to 100 birds a day. Now, they see 20 at most.
Analysis of EYW’s historical wildlife data shows that there were, on average, 1,277 fewer birds observed in 2022 compared to the seven-year annual average of 3,235.
Hartle emphasizes that having reliable data from the wildlife logs is essential for assessing the program’s effectiveness. “We can actually see the impact we’re making,” he says.
The ever-evolving nature of the program allows the airport to address emerging challenges and take advantage of new tools, techniques and technologies to respond to changing wildlife patterns with a “try it and see” approach.
The falconry program, for example, started as a six-month trial. “The results were so successful, we continued it,” Andersen says. “Now, it’s an integral part of the program.”
Collaboration and Cost Management
The success of the program owes much to its collaborative nature. Andersen credits airport management, particularly Executive Director of Airports Richard Strickland, for ongoing support of wildlife safety measures. “It’s unique how receptive airport management has been to the changes we’ve made,” she says. “They are open to new ideas and willing to fund initiatives that work.”
Hartle agrees about the importance of having full support from airport leadership. “It starts from the top down, and Richard [Strickland] has been incredibly supportive,” he says. “Everyone at the airport, from the director to the maintenance staff, is invested in making this a safer place for air traffic.” Hartle add that a phased approach, which allows staff to test new strategies and adjust their practices based on results, has made the program both effective and sustainable.
Keeping Key West chickens away from the terminal is a perpetual challenge.
“A lot of hard work has gone into our wildlife hazard management program,” says Strickland. “Through proactive measures and innovative techniques, we’ve created a safer environment for all involved.”
The budget associated with the wildlife hazard management program fluctuates significantly year to year based on factors such as construction, infrastructure projects and seasonal wildlife behavior. Projects including the new terminal and the commercial apron expansion will require additional wildlife mitigation efforts. Certain components, such as the falconry program, are sometimes funded with Department of Transportation grants, but equipment and personnel costs are covered by the airport.
The program’s cost-effectiveness is one of its key strengths, with measures like falconry helping reduce the need to use other methods such as bangers and screamers.
Long-Term Outlook
Looking ahead, EYW anticipates additional wildlife challenges as the local island environment and construction at the airport continue to evolve. For instance, ongoing efforts will be needed to manage stormwater and prevent the accumulation of standing water, which can attract shorebirds like plovers, whimbrels and sandpipers.
In 2018, the airport contracted Jacobs Engineering to add underdrains and two pumps to route water into the ground and remove standing water from the airfield.
With enplanements at EYW expected to increase 85% by 2043, construction of a new terminal and aprons is requiring collaboration between wildlife staff and project planners.
“When they were developing the plans for the new terminal, I had an opportunity to comment and give input on their plans to mitigate the wetland impact,” Andersen notes.
Both she and Hartle agree that the program’s success hinges on that kind of collaboration continuing, as well as an appreciation for the wildlife being managed.
As Hartle puts it, “It’s a labor of love when wildlife is something you actually appreciate and really enjoy. Throughout my career here, it’s been a blast to pick up on why this bird is at this spot, and what that bird is doing—and how we can take steps to make sure that doesn’t happen moving forward, but still appreciating it while it’s happening.”
