Parent -- G. fortis (image) Princeton University Share Print E-Mail Caption The bird is a member of the G. fortis species, one of two species that interbred to give rise to the Big Bird lineage. Credit Copyright B.R. Grant Usage Restrictions Copyright B.R. Grant Share Print E-Mail 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.