Hatching order affects birds' behavior later in life. Researchers studied several families of zebra finches. The study found that the order in which baby birds in the same nest hatched from their eggs affected the birds' behavior later. When the birds could fly, the younger birds—those that hatched later—were more adventurous than their older brothers and sisters. Researchers believe this helps the younger birds survive by making them able to travel farther from the nest to find their own food.