http://conservationmagazine.org/2014/02/plastic-ingestion-seabirds-worse-thought/

Plastic ingestion by seabirds is worse than you thought
February 12th, 2014

Everyone has heard of the so-called Pacific Garbage Patch. The imagery
is compelling: a giant, continent-sized, swirling vortex of plastic lawn
chairs and newspapers, red party cups and potato chip bags. The truth is
just as troubling, but perhaps less narratively gripping. There actually
are millions of small pieces of plastic floating atop some 5000 square
kilometers of the Pacific (and elsewhere), but they’re mostly
microscopic. It’s estimated that there are about .4 bits of plastic for
every cubic meter of surface water.

Floating bits of human waste are not new. The first documented discovery
of a seabird who had swallowed a bit of trash may be in an 1838 letter
from Jonathan Couch to the Linnean Society in which he describes his
investigation into the stomach contents of a Wilson’s storm petrel that
had washed up: “On examining the stomach of a stormy petrel Mr. Couch
found about half an inch of a common tallow candle, of a size so
disproportionate to the bill and gullet of the bird, that it seems
wonderful how it could have been able to swallow it.”

Perhaps the first formal scientific study of the ingestion of plastic by
seabirds was conducted in the 1960s, which focused on Laysan Albatross.
By the 1990s, researchers had identified plastic in the stomachs of more
than 35% of the world’s seabird species. Even now, an estimated twenty
million new items find their way into the sea each day.