In many bird samples, it is first discovered that the predator's bird makes a warning call
There is a genetic relationship between the bird flocks, and the siblings have the same genes.Although the shouting birds may sacrifice themselves, they can save more siblings and continue their genes
the flock of birds disperses. There is a theory that the calling bird saves its companion by attracting attention to itself, that is, to Self-sacrifice for the benefit of the flock.