Hornbills are colorful birds with large beaks native to Africa and Southeast Asia. They usually mate for life, Emily Bridges, Senior Bird Care Specialist at the Jacksonville Zoo and Gardens, tells Popular Science, and have an incredibly unique nesting process. According to Bridges, hornbills are the only known bird species that nest in this way. The pair (whose names are a call back to one of old Hollywood’s most prolific couples) became mates after Humphrey arrived at Jacksonville Zoo in January. Initially, “we introduced Humphrey and Bacall through side-by-side enclosures so that they could see and hear each other,” says Bridges.