Oil spotting (oleocellosis) was a prevalent physiological rind disorder of citrus fruits that was caused by the action of phytotoxic rind oils released from the oil cells in the flavedo.
After all if it looks like a duck, swims like a duck and quacks like a duck, you don't need to canvas back and forth wandering and whistling in hopes of spotting an uncommon duck to fit the " bill" .
The report says that dozens of Spix's macaws are still alive in captivity but as far as spotting one in it's natural habitat goes, researchers say you can't do it.