EGGS | CHICKS
|
A
bald eagle egg is slightly smaller than a domestic goose egg. The chick
will measure 4 to 5 inches at hatching and weigh only a matter of ounces.
Bald eagles incubate their eggs for about 35 days. They begin incubation
as soon as the first egg is laid. The second egg usually appears within 36
to 72 hours after the first. Occasionally a clutch of 3 eggs will be produced | The
eagle chick will be fed a steady diet of fish, occasionally supplemented
by waterfowl (ducks, geese) or water birds (gulls, cormorants). About 85%
of the chicks diet will consist of fish. Fish like carp, white sucker,
shad, bullhead and sunfish are most frequently caught. The adults will
tear the fish into small strips and offer it to the chick. The chick will
snatch it from the adult's beak and swallow it. The chick will eat as much
as it can at a feeding, storing food in its crop. The crop will appear
distended (enlarged) as it fills, resembling a golf ball at the base of
the neck.
|
HUNTING
& FEEDING
| THE
ADULTS
|
The
male does most of the hunting and scavenging during the early weeks of the
chick's life. The female does the majority of the feeding and brooding.
The male will often eat the head of the fish he catches and then bring the
remainder to the nest. The male will brood and feed the chick when the
female is off the nest. She will leave to stretch, defecate, bathe, preen
and hunt on her own.
| The
male eagle is smaller than the female. He weighs about 10 lbs. and the
female tips the scales at about 14 lbs. Being smaller, he is slightly
quicker and more agile, giving him an advantage in catching prey. She,
being larger, is better able to incubate the eggs and brood the young
chick, using her body to shelter her offspring from cold, soaking rains or
hot sun. The male's wingspan is a little more than 6 feet from wingtip to
wingtip, the female's is between 6.5 and 7 feet.
|
BAND
THE BIRD
| CHICK'S
GROWTH
|
Both
adults are leg banded. The female has a single silver band and was
released as part of the Massachusetts Bald Eagle Restoration Project at
Quabbin Reservoir in 1985. The male has a silver band on one leg and a
blue band on the other. He was likely banded as a chick in a wild nest in
New York state sometime around 1990. He replaced the original male, a bird
released at Quabbin in 1986, when the original bird failed to return to
the territory in 1995.
| The
chicks will be nearly full grown at 9 weeks of age. They will add some
weight as they develop their flight muscles after they leave the nest.
Their wingspan will be as large or slightly larger than the adults at this
time.
|
FIRST
FLIGHT
| CHICKS
LEAVING THE NEST
|
First
flights usually occur at 9 or 10 weeks of age. They are proceeded by
vigorous exercising and flapping. The chick will typically lift off of the
nest by facing into the prevailing winds and flapping. Often its first
flight will be only to the nearest branch above the nest. When they leave
the nest they usually glide to a nearby tree or stump. They will return to
the nest tree frequently and continue to be fed by the adults.
| As
the chicks develop their flight skills they harass the adults and try to
take fish from them. This behavior will last into September. As of
October, the bond between the adults and their young will fade and the
adults will no longer tolerate the harassment from their offspring. This
is time when the young eagles leave the territory, usually heading north
in the early fall to find good fishing grounds.
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EAGLES
& MIGRATION
| YOUTH
TO ADULT
|
Eagles
don't migrate in the sense that robins and bluebirds do. Eagles only
travel as far as they have to in order to find food. This is particularly
true of adult eagles with established territories. Adults will stay on
their territory (roughly 1 - 6 square miles) tyear round, as long as there
is open water nearby when they can hunt fish and waterfowl. Should a
severe winter limit the food supply, eagles will move as far south as
necessary to find open water and suitable hunting grounds.
| The
young eagle will spend the next 4 years of its life wandering across
eastern North America looking for summering and wintering areas where food
is accessible. The mortality rate for eagles during their first year of
life is greater than 50%, but once they have learned to hunt and forage
successfully their chances of reaching adulthood are good. When they begin
to mature at age 4, the eagle will seek a mate and establish a territory.
The territory is usually located within 250 miles of the nest where the
eagle was hatched. There, the new pair of eagles will construct their own
nest but often don't produce eggs or young during their first year as a
pair. They'll return in following years to raise young of their own.
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