Final answer:
Bird calls are an open communication system used by birds to communicate various messages, such as mating and warning of predators.
Step-by-step explanation:
Bird calls are an open communication system. This means that they can be heard by other birds and potentially by other animals or humans. Birds use calls to communicate various messages such as mating, warning of predators, and marking territory.
For example, songbirds have specific calls to attract mates and defend their territory, while crows have different calls to alert other crows of the presence of a predator. Birds also have different calls to indicate danger or to communicate with their young.
This open communication system allows birds to effectively communicate and coordinate with each other, enhancing their chances of survival.
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