In mid-October 2014, the coast of Oregon in the US Pacific Northwest, experienced an increase in seabird strandings from a diatom bloom. The diatoms were not toxic to the birds, rather they matted feathers, making preening difficult and allowing water to reach the birds’ skin, much the same way that oil damages avian waterproofing.
More than 40 birds, mainly Western grebes and common murres, were brought to one drop-off center in the course of a few days. The birds were then transferred to the Wildlife Center of the North Coast for cleaning and reconditioning. Heavy seas compounded the problem by making it difficult for the birds to feed.
A similar incident occurred in 2007 in California, around the same time as the Cosco Busan oil spill in San Francisco Bay. Birds in this instance were found further south, in Monterey County, covered in a yellow-green substance. Testing revealed no connection to the oil spill. The substance found on the birds was linked to a Harmful Algal Bloom (HAB) commonly known as a red tide.
In this situation, the algae were not toxic to the birds, rather the foam residue created by the decaying algae was coating the birds’ feathers, destroying waterproofing and allowing cold water to reach the skin level, just as occurred during this Oregon incident.
Translucent Critters and Battered Birds. 2014. Oregon Coast Right Now. Accessed online 20.10.2014
New Study Links Sea Foam to Unexplained Seabird Deaths and Strandings. 2009. National Centers for Coastal Oicean Science News and Features. Accessed online 20.10.2014