Scientists Reveal Why Seabirds Eat Plastic

Dying algae do not smell very appetizing to humans, but to some seabirds, it is their call to dinner. And unfortunately for them, the smell of plastic calls to them the same.

In a new study published in Science Advances, it was revealed that a good seabird meal is mirrored by the smell of plastic trash -- explaining why so many of them chow down on plastic in alarmingly increasing quantities.

This is surprising, considering that until the mid-20th century, researchers did not think birds could smell at all. The lead author of the paper, Matthew Savoca, explained that many birds have exceptional senses of smell, and seabirds even more so because they have to forage over the vast ocean on food sources -- a feat comparable to looking for a needle in a haystack.

Every year, there are about 8 million tons of plastic garbage dumped into the ocean, and often times, the longer they are there, the more junk grows on them. These plastic and junk start to smell like dimethyl sulfide (DMS), which is a gas that influences everything from the presence of birds to the formation of clouds over the sea.

DMS is one of the main chemicals that signal the presence of algae as that are being eaten by crustaceans that seabirds love. This is why DMS, for sea birds, can be alluring. As noted by The Atlantic, it gives away the presence of plankton and krill, which tells the birds where their meals are.

Because of plastic smelling like DMS, birds believe that they are ingesting food -- explaining why an estimated 90 percent of seabirds have swallowed plastic at one point or another, risking their lives in the process.

Researchers are not sure why plastic wastes smell strongly of DMS, but algae do grow on them. It could be the algae coating the bags that are eaten by other animals, giving off an appetizing scent for the birds looking to get their next meal.