Page 19 - Life of the Eagle
ISSUE : Issue 6
Published by Ronald Caplan on 1973/12/1
male she returns with will be a juvenal (that is, probably under three years old and thus lacking the distinctive bright-white head and tail). If it is the male of the pair that survives, he remains and waits for a possible mate to enter his territory. The mating of Eagles begins during the period of nest-building and continues until the eggs are laid. Herrick says they usually mate twice a day, and that the female gives out a loud, peculiar mating-cry. The male, he writes, "dropped down on the back of the female (who is perched on a branch), and remained for a minute or two, with much flapping of X''ings, This appears to have been an amorous approach, although no sexual call-note was sounded, but later in the same day when both were again in the perching tree, it w'as the female (determined by her greater size) who mounted the male." Herrick thus felt that reports of extraordinary mating flights or actual sexual union in the air were not correct, Broley, hoxvever, witnessed several aerial matings: "rapid chasing flights are often seen.,..Just then he heard an eagle scream and, looking up, saw one of the two he had observed before chasing the other. Sud? denly they came together, locking talons and executed four complete cartwheels, tum? bling dovm several hundred feet before brealcing apart." Broley claimed to have seen this courtship manoeuvre three times, and others are said to have seen the same. I ''' .-.'f!''' Eaglet in natal down; in second down stage; in transition to juvenal plumage. The eggs are externally dull white, but the shells are light blue on the inside. They vary in number from 1 to 4 and are about the size of those of a domestic goose. The size of the egg gradually increases moving northward. The eggs are not always or commonly laid in daily succession. The male and female share the time of sitting on the eggs although the female spends the largest portion of time at the nest • one on the eggs and the other generally on a perch or hunting nearby. Gittens, on the basis of aerial observations, reported that in the first weeks after hatching both Eagles were always sighted within 200-400 yards of the nest. Herrick: "The Eaglets eyes re? mained closed for four hours after its emergence, and the umbilicus, open at birth, soon closed up. The down feathers, still wet with amniotic liquid, showed light, streaked vdth very dark feathers. These black* feathers, on the hinder parts of the body, on drying become a light smoky gray. Its eyes and bill are dark. The Eaglet's shanks, mostly nalced in the juvenal and adult states, are thickly covered fith down, excepting on their undersides, and remain so through the doivn stages. The Eaglet sat up as''soon as it was dry, and using its wings to steady it, cheeped with energy as it crawled about on *all fours,* resting on its shanks. During the first three weeks one or both Eagles are likely to be at the nest all day long. By the time the Eag? lets take on the second-down plumage (darker gray and thicker), while both Eagles are still involved in guarding the nest or bringing in food • they seldom spend time with the Eaglets. As the young increase in size, the regular brooding shifts to a kind of shielding attitude, when the parent, with drooping, half-spread wings, mere? ly stands over the young to protect them from excessive heat or humidity, or to fend off the rain and hail....At four weeks the young Eagle had increased its original weight 11 times (from 85 to 959 g,) and was dark, Quaker gray. At five weeks this Eagle weighed 1998 g. (4 pounds, 5 ounces), still moved about on shanks but could rise to its toes and take a few tottering steps. At 6-7 weeks this young Eagle was in full transition to the juvenal dress, with gray down being everywhere sprinkled with dark brovm feathers," Here is a da m description of the sort of exercises the young Eagles pursue as they learn how to fly. "June 15, the light increased...the two Eaglets were standing close together with bodies apparently touching, and dozing if not sound a- sleep; they were perched on a stick at the margin of the nest and were facing out- Cape Breton's Magazine/19
Cape Breton's Magazine