Occupancy of Territory: The adults arrive back from the wintering grounds from October through November. The most intense repair period is January through March. Aerial courtship is spectacular with the pair often flying in tight unison with one bird slightly behind and above the other.
Large loops are flown over a considerable distance of the territory. Usually the pair break off this courtship flight, return to the area of the nest tree and proceed with loud unison calls where the head is thrown back. As the intensity and head throwing becomes more synchronized there seems a greater likelihood of the male immediately mounting the female. Mating always takes place with the female standing on a branch, the nest or some solid sub-straight.
It never takes place in the air. Egg Laying: Eggs take 3 or 4 days to move from the ovary through the oviduct where they collect the surrounding protein and membranes and finally the shell. One to three eggs are laid by bald eagles though there is at least a record of four eggs appearing in a Montana nest. Other instances of 4 eggs were known to result from two females laying in the same nest during the same season.
Each egg is laid about 3 days apart. Incubation starts with the laying of the first egg. Each egg also takes 35 days of incubation — plus or minus a few hours. This means that the chicks hatch 3 days apart. The synchronization of all of this is more marvelous than the small variation witnessed. Different pairs are more closely synchronized from year to year than necessarily from neighbor to neighbor.
And the difference between different years for the same pair is very small. If a pair lays their first egg February 27 one year it is likely to be within a day or two of that date every year. Hatching : is a very delicate matter and seems to take place largely at night or early morning. Chicks remain in the nest for ten to twelve weeks. A week or two before they fledge, they can be seen on the rim of the nest exercising their wings and holding onto the nest with their talons. They flap their wings and may even lift off the nest.
Biologists estimate one in seven eaglets fledges prematurely, either falling or jumping from the nest before it can fly. Once their muscles and wings are strong enough, eaglets are ready to leave the nest. What prompts the chicks to fledge is a matter of speculation, but at some point, the parents cut back on the amount of food they provide their young, and they may even use food to lure the chicks away from the nest.
Males fledge at an average of 78 days, and females fledge at an average of 82 days. Research in Southeast Alaska shows fledging there occurs on average in mid-August. Once it is large enough, the egg tooth will come into contact with the inside surface of the egg. If you are observing a nest with a camera and microphone, you can hear the tiny cheeps the eaglet makes even before it hatches. By the time they are 9 — 11 days old, the first down is replaced by a second down which is much darker in color.
Feathers begin to appear when they are about 24 days old. These are always very dark when they start to appear. The coloration from a baby eagle to an adult eagle changes over the course of years until the beak and eyes turn yellow, and the head and tail feathers turn white.
As hatchlings, eaglets are in the primary or natal down phase and are fluffy grey in color with a whitish head and throat. By their third week, the secondary down appears and is a longer, thicker, dark-grey wool covering. The juvenile eaglet is fully feathered by 10 weeks of age and exercises its wings by jumping up and down in the nest. Bald Eagles face challenges due to habitat loss and other impacts. Help eagles in Florida by joining Audubon's Friends of Eagles program.
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