• Nestling. About three days after hatching, the baby birds can open their eyes. Now they’re nestlings. Downy fluff emerges to cover their bare skin. Their feathers begin to appear, and they generate their own body heat. They still rely on parents for survival, but after about 14 days, they have become fully feathered and mobile enough to fledge the nest.
• Fledgling. The fledglings can leave the nest and hop, flutter and walk about on their own. They rapidly acquire a set of flight feathers and start taking short flights. They will, however, continue to associate with parents for up to three weeks until striking out on their own as juveniles.
• Juvenile. It takes about nine months for juvenile birds to acquire full adult plumage and become capable of breeding, but they’re essentially on their own.
• Adulthood. The birds are sexually mature, capable of having their own babies.
IN THE SKY: From David Dundee, Tellus Science Museum astronomer: The moon will be new on Monday. Venus, Mars, Jupiter and Saturn (rises just after midnight) are low in the east a few hours before sunrise. Mars and Jupiter appear close together in Sunday’s pre-dawn sky.
Charles Seabrook can be reached at email@example.com.