the explanation was simple, i'm talking with evidence and simple language, there is a species of bird that fishes in a strange way: they live on the beach rocks and throw pebbles into the water so that the fish can be fooled about food, then the birds catch the fish very easily, when they are above water. the first behavior of the chick is: immediately after the eggs hatch: they crawl to the top of the rock and throw stones into the water for the big lie