Photo: Mr. TinDC
Seabirds will eat just about anything they can get their beaks on. Their tenacity and voracious appetites are usually experienced firsthand by anyone bringing a picnic basket to the beach, but the problem goes well beyond human snacks. Our feathered companions are developing an unquenchable thirst for plastic, and the addiction is proving fatal to their species.
Beaches have a knack for attracting litter and pollution. Cleanup efforts on Hawaii Island by the Hawaii Wildlife Fund prove just how bad things have gotten in the last five years. Volunteers traveling along a ten-mile coastline recently collected over 1,300 pounds of trash and 200,000 plastic fragments in a 48-hour “treasure hunt.” Approximately 169 tons of garbage have been removed from the area over the last 11 years, and more than 15 tons of new debris wash ashore annually.
More disturbing is that these are mere fractions of what’s likely moving through America’s oceans. Sea-farers have often reported “floating islands” between California and Japan, never realizing that what they’re staring at are growing garbage patches that endanger seabirds and wildlife along the way.
So what would drive an animal that normally feeds on krill to a nasty chunk of plastic? Matthew Savoca of UC Davis says he’s found the answer.
“Animals usually have a reason for the decisions they make,” he explains. “If we want to truly understand why animals are eating plastic in the ocean, we have to think about how animals find food.”
It’s an interesting perspective. Indeed, animals can’t head to the nearest grocery store to buy milk and bread, so they rely on natural instincts and senses to locate their meals. According to Savoca, it’s the smell of the garbage that’s driving the birds’ eating habits.
“If your nose told you that you can find food here, it’s much more likely you’ll let your guard down and eat garbage by accident,” says Savoca. He says the smell of plastic usually reeks of algae, a common “dinner-trigger” for gulls and related waterfowl.
Algae suggests the presence of krill, a staple food for dozens of aquatic species. When algae die, krill gather underneath to feed on what remains. The algae then release a sulfuric defense odor, informing birds of the buffet that lies in wake below the surface.
But when plastic washes into our oceans from sewers and landfills, it often gathers organic material the same way rocks do. Sulfuric fumes are released, leading the animals to dive in to consume what would otherwise be natural prey but is instead garbage.
“The birds are not making dumb decisions,” Savoca says. “It’s just that plastic can be very deceptive in this regard.”
The circumstances give rise to some serious questions: Why are our oceans so dirty? How much plastic are we producing each year, and why does so much of it wind up in coastal waters?
Scientists have been monitoring seabird behavior for decades. Plastic ingestion has been recorded for over half-a-century, but numbers have substantially risen since the 1980s. Fifty years ago, only five percent of seabirds were feasting on plastic. Twenty years later, figures jumped to around 80 percent.
Now that number stands at a rough 90 percent. According to Chris Wilcox of Australia’s Commonwealth Scientific and Industrial Research Organization, every seabird will be consuming plastic by the year 2050. As manufacturing rates increase, so do the birds’ ingestion patterns. Cleaning our beaches and oceans is a lost cause if we’re not willing to stomp the brakes on plastic production once in a while.
“Global plastic production doubles every 11 years,” Wilcox states. “So in the next 11 years, we’ll make as much plastic as we’ve made since plastic was invented. Seabirds’ ingestion of plastic is tracking with that… Essentially, the number of species and number of individuals within species that you find plastic in is going up fairly rapidly by a couple percent every year.”
While the health effects of plastic consumption are not fully recognized, the dangers they present are undeniably real. Sharp-edged plastic is known to puncture birds’ stomachs and internal organs. Sometimes, they consume so much that there isn’t any room left for natural food. This can affect a bird’s body weight and overall health, and Wilcox mentions that seabird populations have fallen by nearly 70 percent.
“Seabirds are going extinct,” he says. “Maybe not tomorrow, but they’re headed down sharply. Plastic is one of the many threats they face.”