All-black Carrion Crow Nestlings (image) Uppsala University Caption All-black carrion crow nestlings from a German population west of the hybrid zone. When crossing the zone, plumage colouration changes rapidly to the grey-coated hooded type. Credit Jochen Wolf Usage Restrictions May be published in connection to reports about research from Uppsala University. 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.