A study published in Science Advances found that plastic debris "emits the scent of a marine infochemical, creating an olfactory trap for susceptible marine wildlife".
Using mesh bags tethered in various parts of the sea off the west coast of the US containing LDPE, HDPE and PP beads, researchers found that three types of plastic acquired a particular signature smell.
The odour, which some seabirds find irresistible, came from diamethyl sulphide (DMS), which smells like decaying seaweed.
DMS also results when plankton, which collects on waste plastic objects, breaks down.
"These seabirds actually use odours to find their way around in the world and to find food," Matthew Savoca, of University of California, Davis, told the BBC.
"We found a chemical on plastic that these birds typically associate with food, but now it's being associated with plastic.
"And so these birds might be very confused – and tricked into consuming plastic as food."