Chris Wilcox and colleagues at Commonwealth Scientific and Industrial Research Organisation (CSIRO) and Imperial College combined published studies of plastic in seabird stomachs with ocean-plastic distribution models and species ranges to estimate how widespread ingestion is.
In studies from 1962 to 2012, 80 of 135 seabird species (59%) had eaten plastic, and on average 29% of the birds examined had plastic in their gut. Adjusting those studies for species and year, the model estimated that 90% of individual seabirds would have plastic in their gut if studied today, and that 99% of all seabird species will be affected by 2050 if current trends continue. The highest risk was in the Tasman Sea between Australia and New Zealand, where many species overlap with plastic-rich waters.
The study matters because it showed that plastic ingestion is not confined to a few well-studied species or hotspots but is close to universal.
The 90% and 99% figures are model estimates, not direct counts; the underlying studies vary in method and date. Two of the authors thank CSIRO and Shell’s Social Investment Program for support.