Several days after the spill, birds like this American Coot show up in affected areas with full or partially-oiled plumage. Even small patches of oil can disrupt a bird's thermoregulatory process. In this photo, it's easy to see how the oil prevents the feathers from laying flat in proper position, exposing the bird to the elements.
Note: Oiled Wildlife Care Network (OWCN) was called for rescue on all birds pictured in this series of photos.
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These photos were taken while volunteering with the oil spill efforts to locate oiled birds and wildlife. OWCN was notified about all oiled birds found.