Monday #3

Seeing it's that time again, with an egg in the nest, here's some info on Bald Eagle nesting and eggs from Bent's.

Eggs.--Two eggs almost invariably make up a full set for the bald eagle, sometimes only one, and rarely three; in two or three cases four eggs have been found in a nest, but these may have been the product of two females. The eggs vary in shape from rounded-ovate to ovate, the former predominating. The shell is rough or coarsely granulated. The color is dull white or pale bluish white and unmarked, though often nest stained. Very rarely an egg shows a few slight traces of pale brown or buff markings.

The measurements of 50 eggs from Florida average 70.5 by 54.2 millimeters; the eggs showing the four extremes measure 78.8 by 56.2, 71.1 by 57.6, and 58.1 by 47 millimeters. The eggs are ridiculously small for large a bird. (Compare the relative sizes of the eggs of the ruddy duck, the sandpipers, or the hummingbirds.) Consequently the little eaglet requires a long time to develop.

Young.--The period of incubation is about 35 days, according to the most careful observers, though it has been otherwise estimated. Both parents assist in incubation and in the care of the young. Mr. Nicholson tells me that at every nest he has visited after dark he has found both birds at the nest, one incubating or brooding and one perched near it. In one instance the incubating bird remained on the nest until the climber nearly reached it. Usually an eagle will leave its nest as soon as an intruder is seen approaching it, but occasionally one will sit closely until the tree is rapped. The food of the young seems to be about the same as that of the adult, to be referred to later. The behavior and development of the young will be discussed under the northern race, on which more information is available.