Gulls and Plastic
Glaucous-Winged Gulls are the common gull seen throughout the year in the Salish Sea and along the coast. They scavenge for dead or weak squid, fish, mussels, and the like, and sometimes picks up human garbage. Are glaucous-winged gulls ingesting plastic? Fortunately for researchers, gulls, like owls, albatross and many other birds regularly regurgitate masses of undigestible material such as bones and shells. These masses, called boli (the plural for bolus), can provide researchers with data on what the birds consume – including how much plastic!

Gull Bolus Study
Protection Island National Wildlife Refuge, in the Strait of Juan de Fuca, has the largest nesting colony of glaucous-winged gulls in Washington State. What better place to investigate whether plastic is being ingested by this gull population?

Since 2007, PTMSC staff and volunteers have collected and examined over 400 boli from Protection Island to try to answer this question.

Boli were collected during the breeding season, after the eggs were laid but before they hatched, in an effort to avoid unnecessary stress on the birds and their young.