Spikes, loud noises and a variety of landscaping measures are among the approaches taken to prevent bird and airplane collisions at airports in the U.S. Virgin Islands, wildlife biologist Shane McKinley said at a Tuesday meeting of the Audubon Society on St. John.
“Different approaches are needed depending on the types of birds present and what attracts them to the airport,” he explained.
Ducks, herons, laughing gulls, cattle egrets, barn swallows, kestrels, or red-tailed hawks may be in the areas around Virgin Islands airports at various times of the year, each with its own needs and its own stresses.
McKinley’s team, part of the U.S. Department of Agriculture’s Wildlife Services program, is responsible for keeping the birds from making contact with arriving or departing planes. The team conducts frequent hazard assessment surveys to determine what types of birds are present and then devise appropriate dispersal strategies.
“Make it look like a desert” is one method McKinley described for keeping away the laughing gulls that nest during the summer on offshore islands near the St. Thomas airport. “They mostly come to drink water that collects on the runways, so removing that standing water will reduce the attraction for them.”
“Selective mowing” is another strategy. In the winter, flocks of barn swallows may be foraging for insects, specifically for beetles, wasps, butterflies, moths and bees. Keeping grass mowed short helps limit the available insect population. At other times of the year, it may be better to let the grass grow tall because some birds, such as herons and egrets, don’t like walking through high grass.
For raptors, bird repellent spikes are helpful. Kestrels like to sit on high poles or wires watching for lizards, mice and other prey below. They swoop down for a quick strike and often bring their catch back up to eat it. Covering perching spots with sharp spikes keeps the kestrels from getting comfortable.
“Cannons and pyrotechnics are also effective for scaring off many birds quickly without harming them,” said McKinley. At the St. Croix airport, cattle egrets are attracted to the garbage in the nearby landfill, and frequent noise blasts throughout the day are needed to drive them off, whereas the laughing gulls are less bothered by loud sounds.
Although protecting planes from bird strikes is clearly an important issue for public safety, the Audubon Society is generally more concerned with protecting birds and other wildlife from dangers caused by people. For example, the national organization began as an effort to keep egrets from being killed to make feathered hats.
Audubon Society members were interested to learn that, in some cases, McKinley’s team has also taken actions to protect endangered birds from human-introduced pests. In one instance, the team worked to remove invasive rats from offshore islands where rare birds such as red-footed boobies or masked boobies prefer to nest. The birds come to these small islands for security from predators, but rats can swim over and eat the eggs out of their nests.
During the meeting, the group also considered the possibility that new development projects near small islands could result in additional human-related problems for these birds and other offshore nesters like roseate terns. IMcKinley also described how Wildlife Services also manages other types of conflicts between people and wild animals, particularly involving the protection of agricultural property from feral pigs, the response to threats posed by rabid animals, or helping homeowners overwhelmed by a sudden influx of iguanas.