After two cattle egrets flew into the engines of a plane at Owen Roberts International Airport on Oct. 2, 2009, taking out an engine and a measurement instrument, all passengers had to be deplaned and put on other flights. The aircraft was unavailable for five days.
Though nobody was injured, the inconvenience was a wake-up call for the airport over the management of wildlife that flutters, crawls or slithers onto the runway.
“It really causes a major disruption,” said Cayman Islands Airports Authority Chief of Safety Management Andrew McLaughlin.
On Monday, a conference room at Airports Authority headquarters was packed with airline representatives, employees of environmental nonprofits and concerned citizens as Mr. McLaughlin discussed the airport’s plan to cope with dangerous wildlife on airport runways.
“For years, the airports had the attitude that it wasn’t our problem,” he told the crowd. “But surely there must be something that airports can do.”
With the help of Edward Cleary, a wildlife specialist for the Federal Aviation Authority, the airport conducted a yearlong hazardous wildlife study. Veterinary students from St. Matthew’s University assisted in the study, observing wildlife and their habits.
The study showed that twice a year, the Cayman Islands are smack in the middle of a migration pattern for many birds. Cattle egrets, snowy egrets, swallows and iguanas all make permanent or temporary homes on the runway. There are plenty of occasional visitors, too.
“Last year during crab season the land crabs closed the entire runway,” said Mr. McLaughlin.
But why do they come to the airport to begin with?
“Animals are looking for food, water and shelter,” he explained, adding that the airport is also attractive because it’s free of most natural predators. “So if we can make the airport less attractive, they will not want to come.”
Mr. McLaughlin detailed the exhaustive list of techniques the airport has employed to dispel wildlife – some more effective than others. The efforts begin with mitigating standing water, filling in ponds, removing hiding places like grass, trees, rocks and old structures, and putting up physical barriers such as electric fences and netting.
Another regular method is the use of a propane cannon, which produces the same sound as a 12-gauge shotgun, scaring birds for up to two or three days.
“We’ve found bird droppings on top of the cannon. They’re sitting on the air cannon that’s put there to scare them away,” said Mr. McLaughlin. Plus, the airport’s neighbors tend to get annoyed with the constant noise. “We try to cut it off by 8 p.m. out of courtesy,” he said.
Using border collies and falcons as natural predators has also occasionally seen results, but having large animals on the runway can end up causing more problems than it solves. Employees have tried hopping in vehicles and chasing the birds using horns and sirens and putting up decoys of predators like scarecrows and owls. However, the birds quickly learned they were not a threat.
“Traps can also be an effective tool,” he said. But they aren’t perfect, either. “We bought the best traps, took all day to try to put them together, and sat there waiting. Three days went by, and on the fourth day a big old bird built a nest on top of the trap.”
Last year, the airport found its most effective technique yet: a fogger dispersing a chemical called methyl anthranilate, which is safe for humans, animals and the environment.
“It smells like grape soda. It doesn’t harm the bird, but it bothers them like tear gas. From the first moments after we bought the machine, the birds hated it. It can even be mounted on the top of the truck so we can disperse it within minutes of the plane landing.” In September, during swallow migration, a flock of almost 500 birds descended on the airport during heavy flight time. Using the fogger, workers managed to disperse them in 30 minutes, leaving the airport safe and delay-free.
The last resort is culling, or what Mr. Mclaughlin calls “lethal control, carried out in the most humane fashion possible.”
He said the shooter has to be sure of the instant death of the animal. If that does not occur, shooters “must make every effort to locate wounded or orphaned animals to quickly and humanely cause immediate death,” he said. Plus, “one shot scares the rest of them away.”
He said the Cayman Islands Sport Shooting Association was involved in the earlier days of culling, but since then, the airport has worked to train its employees to do the job. He said two employees are currently qualified to cull.
The airport has not had a damaging strike since 2014.
“No place can be 100 percent free of a wildlife strike,” he said. “But by making the place less appealing and by understanding why they come, we can lower our chances,” he said.
For further studies, the airport is seeking volunteers interested in observing wildlife – learning why they come, what they eat and how they behave, and in the process making the airport safe for animals and people. To volunteer, email [email protected]