I expected that oil soaked feathers would lose their buoyancy. The oil soaked feathers appeared to float just beneath the surface but this was not conclusive. Birds soaked in oil are known to drown because they lose their buoyancy. I would conclude that emulsified oil as a mousse clings to the feathers more so than oil. Applications Oil obviously coats bird's feathers to a high degree.
Emulsified oil appears to coat feathers even more completely than regular crude oil.
The danger increases with emulsification and therefore increases the risk to the sea birds.