Effects of oil and oil burn residues on seabird feathers

•Exposure effects of fresh oil and burn residue was studied on seabird feathers.•Burn residues had similar or more damaging effects on feathers compared to the oil.•Feather microstructure damages was measured even for thin, not visible sheens.•Grane crude was slightly more damaging than IFO30 for both fresh and burned samples.

It is well known, that in case of oil spill, seabirds are among the groups of animals most vulnerable. Even small amounts of oil can have lethal effects by destroying the waterproofing of their plumage, leading to loss of insulation and buoyancy. In the Arctic these impacts are intensified. To protect seabirds, a rapid removal of oil is crucial and in situ burning could be an efficient method. In the present work exposure effects of oil and burn residue in different doses was studied on seabird feathers from legally hunted Common eider (Somateria mollissima) by examining changes in total weight of the feather and damages on the microstructure (Amalgamation Index) of the feathers before and after exposure. The results of the experiments indicate that burn residues from in situ burning of an oil spill have similar or larger fouling and damaging effects on seabird feathers, as compared to fresh oil.