The South American Oilbird (image) Cell Press Caption The South American oilbird is the planet's top-ranked most evolutionarily distinct bird species. Photo taken by Walter Jetz in Humboldt's Cave, Venezuela. Credit Walter Jetz Usage Restrictions Credit required. Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.