A Galápagos Island warbler population does not recognize call signaling mainland threat

Researchers are realizing that animal communication is more complicated than previously thought, and that the information animals share in their vocalizations can be complex. For example, some animals produce calls that warn of specific dangers in the environment, such as a predator, and these calls can even contain information about the type of predator (e.g., flying vs. ground predator). These calls are known as referential calls.