It isn’t just turtles and whales that suffer at the hands of plastic pollution – even the toughest predators of the skies can fall victim. A new study has found microplastics in the guts of birds of prey in Florida, including hawks, ospreys, and owls. In fact, the researchers discovered microplastics in 100 percent of the birds they examined.
Reported in the journal Environmental Pollution, scientists from the University of Central Florida (UFC) dissected the stomach contents of 63 birds of prey representing eight different species and found microplastics in every single individual, amounting to a total of almost 1,200 pieces of microplastic. The birds were either dead before arriving at the research center or had died within 24 hours of arrival with no food consumed during captivity. Blue and clear microfibers accounted for the vast majority (86 percent) of total plastics, followed by an assortment of other microfragments (13 percent), macroplastics (0.7 percent), and microbeads (0.3 percent).
A little over 60 birds of prey in Florida is not a huge sample size, so it's not possible to make any firm conclusions about how pervasive the problem is nation-wide or even state-wide. Nevertheless, the researchers argue their results clearly show a worrying trend.
"Birds of prey are top predators in the ecosystem and by changing the population or health status of the top predator, it completely alters all of the animals, organisms, and habitats below them on the food web," Julia Carlin, the study's lead author and a graduate of UCF's Department of Biology, said in a statement.
Microplastics are known to accumulate in apex predators that sit at the top of the food chain because plastic doesn’t decompose and can be passed on from animal-to-animal through trophic transfer. The bird itself might not be directly eating microplastics, but their prey might be, so it ends up accumulating in their gut. Numerous past studies have documented increasing amounts of microplastics in the bodies of fish, marine birds, and sea-dwelling invertebrates, but this is the first piece of research to quantify the presence of microplastics in birds of prey in Florida.
Unusually, the new research found that fish-eating osprey had significantly less plastic in their digestive tracts than red-shouldered hawks, which tend to eat land-dwelling rodents. Given how widespread microplastic pollution is throughout marine environments, this is perhaps surprising.
While eating plastic is certainly not considered a healthy part of anyone's diet, the finer details of microplastic pollution are not yet fully understood. That said, an increasing amount of evidence shows that microplastic pollution has a detrimental effect on wildlife and the ecosystems that support it. Clearly, larger microplastics can be a danger when ingested as they can become lodged in their digestive tract, but there's also some evidence that suggests even small pieces could potentially hold a toxic effect on animals too.
"We have all benefitted from the convenience of plastics, but plastics do not go away once produced," Walters concluded.