Peregrine Falcon chicks are helpless. One parent (often the female but sometimes the male) stays with the chicks while the other finds food for the brood. Eyases eat an incredible amount of food – but then, they double their weight in only six days and at three weeks will be ten times birth size. 

Newly hatched chicks are wet and covered with white down. But by three weeks of age, brownish juvenile feathers can be seen poking through the white fuzz. By five or six weeks of age, the white fuzz has been completely replaced by brown feathers. The eyases can be observed jumping around and testing their wings, getting ready to fly.