Of course you can tell at first glance that oil is incredibly bad for birds. But how exactly does oil harm birds? Well, according to our experts, oil is deadly for a few reasons: First, it will poison them when they attempt to preen the oil off the feathers and ingest it directly, severely damaging the respiratory and digestive systems. Second, oil on a bird’s feathers restricts the feathers’ ability to insulate the bird from cold water and weather, causing birds to lose heat at a high rate. Last, when oil sticks to their feathers, it makes the birds much heavier – when it’s harder to swim, float and fly, birds can’t feed or rest. The IBRRC has even more information. (photo of a scaup during 2007 S.F. Bay oil spill by Glen Tepke)