Oil spills from oil tankers and ships can pollute water and harm marine life. An experiment showed that oil causes feathers to clump together, which would prevent birds from flying or keeping warm. Untreated water did not affect feathers, but soapy water caused them to clump slightly. Oily water made feathers clump very tightly, which could leave birds unable to fly or swim and risk freezing or taking in oil when cleaning themselves. The oil spill would significantly impact birds and other sea creatures.