What is the scientific explanation for what gives birds the instinct to migrate to specific locations?
I think the scientific explanation is that this is a behavior trait that is hard-wired into their brains through the wonders of natural selection. When animals are born (including people), their brains (and actually their entire physical bodies) are pre-programmed to do certain things. They eat when they’re hungry. They “feel” hunger when they haven’t eaten in a while. They run when they’re scared. They feel scared when they see, smell, hear, or feel certain types of things. Their hearts beat. Their eyes blink. They sleep when they’re tired. Having these characteristics gave them the ability to survive as a species and be around today to be observed by us. Animals who had hearts that didn’t “know” to beat automatically didn’t last long. So flying south for the winter is an instinct that allowed birds to survive. The many birds who lacked that instinct had more difficulty surviving.
