Beak Morphology (IMAGE) Uppsala University Caption The common cactus finch has a pointed beak adapted to feed on cactus whereas the medium ground finch has a blunt beak adapted to crush seeds. Their hybrid progeny have an intermediate beak morphology adaptive under certain environmental conditions as explained in this paper. Credit Sangeet Lamichhaney, Rosemary and Peter Grant. Usage Restrictions May only be published in connection to reports about the research published in "Female-biased gene flow between two species of Darwin's finches" or after permission from the photographer. License Licensed content 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.