The time is fast approaching when the young will begin to take their first flights. They are about 50 days old and should begin to fly between 55 and 60 days.
I was just watching the cam and saw one of the young revving up his wing muscles by flapping. Birds have two very large breast muscles (think chicken breasts) that power flight. Instead of a flat sternum or breast bone like humans have, birds have a protruding ridge called a keel. (Like the keel of a boat.) Muscles anchor to this keel and the wing bones. Young birds do not have developed breast muscles and spend time flapping to help them get in shape. All of the young birds will begin to flap a lot.
Its also getting hard to tell adults from young in the nest. Sometimes the young still lay down: the adults almost never lay down.
One clue to watch for: the adults are still feeding the young and will continue to do so for another month or so. As soon as the young birds start flying, they will also begin learning how to fish. No doubt they already scan the water from their nest.
I hope you are enjoying the cam. Please email firstname.lastname@example.org if you have any questions or comments. We are looking for people to help write more blog updates. I will be ending my position in two weeks and will no longer be able to update the blog....