Cuckoo chick

A small bird is feeding the large fat chick. Tiny parents bring food to the enormous baby 200 to 300 times a day, and sometimes even more. But the baby is not theirs. His real mother is a cuckoo, who planted her egg in their nest two weeks ago and will never come back to visit. A series of extraordinary instincts and adaptation mechanisms helps cuckoos waive what is probably the most troublesome business of all — childrearing.