Greater Antillean Bullfinch (image) Harvard University Caption Greater Antillean bullfinches (Loxigilla violacea) use their deep and wide beaks to crush seeds and hard fruits. Harvard researchers have found that the molecular signals that produce a range of beak shapes in birds show even more variation than is apparent on the surface. Credit Photo by José M. Pantaleón Usage Restrictions None 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.