Plastic ingestion in marine-associated bird species from the eastern North Pacific

•Multi-species surveys are needed to understand the extent of plastic ingestion.•We examined the stomach contents of 20 bird species from the eastern North Pacific.•Low levels of plastic ingestion were observed in five species of alcids.•Fifteen other species were examined, but small sample sizes limit generalizations.•Importance of continuing to monitor a wide variety of marine species is emphasized. In addition to monitoring trends in plastic pollution, multi-species surveys are needed to fully understand the pervasiveness of plastic ingestion. We examined the stomach contents of 20 bird species collected from the coastal waters of the eastern North Pacific, a region known to have high levels of plastic pollution. We observed no evidence of plastic ingestion in Rhinoceros Auklet, Marbled Murrelet, Ancient Murrelet or Pigeon Guillemot, and low levels in Common Murre (2.7% incidence rate). Small sample sizes limit our ability to draw conclusions about population level trends for the remaining fifteen species, though evidence of plastic ingestion was found in Glaucous-Winged Gull and Sooty Shearwater. Documenting levels of plastic ingestion in a wide array of species is necessary to gain a comprehensive understanding about the impacts of plastic pollution. We propose that those working with bird carcasses follow standard protocols to assess the levels of plastic ingestion whenever possible.