The Bald Eagle
by Janice G
Class 703- Dolphin Senior Public School
Even though the Bald Eagle is one of the most recognized birds, only a
few people have seen it. The reason for this is the death rate of eagles
that occurred in the 1950's. Thanks to Canadian Charles Broley and scientist
Rachel Carson in 1973, an Endangered Species Act granted the Bald Eagle
full protection. The eagle population is now slowly rising. Just recently,
the Bald Eagle was removed from the endangered species list in the United
States. The North American Bald Eagle is the symbol for the United States.
It decorates many American belongings such as government buildings, quarters
and silver dollars. Its scientific name is Haliaeetus Leucocephalus (meaning
white-headed eagle). On average, male Bald Eagles measure 90.5 cm from
head to toe. They have a wingspan of approximately 200 cm. and weigh about
3 to 4.5 kg. Females are larger than this. They weigh about 6 kg. and
have a wingspan of 98.5 cm. The eagles' head and tail are white, and its
body is dark brown. Long ago, bald headed meant white headed. That is
how the eagle got it's name.
The Bald Eagle is part of the sea and fish eagle group, one of four groups
that eagles are divided into. Sea and fish eagles mostly feast on water
animals. Eagles are also called raptors, birds of prey. This means that
they eat other animals. The Bald Eagle is a Falconiformes raptor, raptors
that hunt mostly during the day.
The size of Bald Eagles can be different, depending on its age and gender.
Young eagles are often larger than adults. This is because a young eagle's
tail and wing feathers are longer than an adult's feathers. Even though
this may be, young eagles still weigh less than adults. Like most birds
of prey, the females are larger than the males. This helps females defend
their nests, eggs and young. The males, being smaller, can manoeuvre more
The eagles eyes are probably the most sharpest eyes in the world. It can
see 4 to 8 times better than human eyes. Eagles have 2 focusing depressions(foveae)
in the retina of each eye. This can allow the eagle to look forward and
sideways, at the same time. They also have a much greater resolving power
than human eyes. Eagles have 2 eyelids. The inner one moves from front
to back every 3 to 4 seconds. It wipes dirt and dust from the eye.
Talons and Beak
Bald Eagles have very strong feet. The undersides of their feet are very
rough and bumpy. The eagles have 4 toes, 3 in the front and 1 in the back.
On the tips of their toes are long, curved talons which they use as weapons(when
needed). Bald Eagles have no teeth. They swallow their food in pieces.
They use their beaks to tear their prey in pieces. Sometimes, to finish
the life of its prey, the Bald Eagle uses its hooked like beak and jabs
its prey. Skeleton The Bald Eagles is skeleton is thin, hallow and filled
with air spaces. Many of the bones are joined, which makes the eagle strong.
This kind of skeleton helps raptors to fly. An eagle's skeleton weighs
less than half the feather's weight.
eagles migrate regularly from a summer range to a winter range, and back.
The Bald Eagle migrates southward, mainly during October and November,
to its wintering grounds. The majority of them winter in southern United
States and Baja California. In late winter and early spring the Bald Eagle
migrates back to Alaska and Northern Canada. It travels in the afternoon
unlike in the fall migration. This is because in spring, the availability
of thermals (columns, or currents, of warm air that rise up in the sky)
are only at its best in the late afternoon, due to the bad weather. The
Bald Eagles' habitat consists of tall trees, large bodies of water, rocks,
cliffs and open spaces such as beaches and sandbars. This allows it to
roost, perch or catch and kill prey. In the cold months, which the Bald
Eagle can survive, the water usually freezes over. So when the eagle winters,
it will most likely hunt or find prey on land instead of in the water.
Or, it moves to southern areas of open water. There are Conservation Groups
and Rehabilitation Centres across North America. They are helping to protect
the areas where eagles live, and to pass laws to control pollution.
Eagles are scavengers and hunters. They eat a variety of foods. Its diet
mainly contains fish, birds and mammals. They prefer to eat fish, and
waterfowl the most. The fish that they eat are often poisoned. This is
- Bald Eagle
- Fish eats
fish eats Plankton
healthy Bald Eagles are able to go a week without food, they eat 6 to
11 percent of their body weight everyday. Bald Eagles need this in the
winter because they use more energy to keep warm. Photoperiod plays a
major role on the eagles' diet. It allows the ice to melt so eagles can
catch fish. Also, it lets plants and insects grow or live. Animals that
eat plants and insects have food. These animals are food for other animals,
like Bald Eagles. In the winter, it does the opposite. Photoperiod also
tells eagles when to migrate, breed, and when to molt their feathers.
When the water turns into ice, eagles can no longer eat fish. This is
when they steal and scavenge carrion. Eagles only hunt for small animals
when they cannot find or steal prey. Some birds try to fight for their
food. They almost always shamefully lose to the Bald Eagles sharp talons
and pointy beak.
temperature and weather affects the way a Bald Eagle would go about its
daily routines. If on its summering grounds the temperature gets to hot,
a Bald Eagle would fly south to a warmer spot. If it is freezing, a Bald
Eagle may not find food, and die of starvation. Usually, in cold temperatures,
Bald Eagles eat more to get energy and stay warm. A drought affects virtually
the whole food chain. Plants would have no water and die. Insects would
die because there are no plants, and so would deer, geese, ducks and rodents.
The population of animals that feed on insects and these animals start
to decrease. That leaves less food for the Bald Eagle.
mating season of the Bald Eagle usually occurs during mid-May, after the
coldest weather has passed. If eggs are laid too early, the embryos may
freeze. Once Bald Eagles have found a partner, they mate for life. If
one of them were to die, the other one would find another partner. Couples
mate by doing a Sky Dance. (refer to the next page for a diagram of the
If a couples'
eyries (currently used and back- up nests) were destroyed, the two birds
would not mate. Instead they would start building other eyries. Female
eagles lay between 1 and 4 eggs. Most often 2. The eggs are laid 2 to
4 days apart. The first egg is usually largest and heaviest. After incubating
in an eyrie for about a month, the first egg hatches, the others in the
following days. The next few weeks are very busy for the parents. When
the eaglets squeal in a food begging call, the parents quickly bring food
to the nest. Parents have to rip the prey into small pieces for the young
to eat. Feeding takes place every 3 to 4 hours. After 6 to 7 weeks, the
eaglets are able to rip the prey by themselves, leaving the parents easier
jobs. By the migrating time, the eaglets have learned to do a lot without
the help of their parents. They start to migrate earlier than the adults,
and arrive latest at their wintering grounds. Some may die of starvation
if they are lost and unable to find a good wintering spot. On average,
a Bald Eagle lives 30-40 years.
have a troubled time looking for food when lakes and rivers are frozen,
and a thick layer of snow covers the ground. So in the fall, when the
days get shorter, Bald Eagles get an urge to migrate, due to the cold
weather. That is why they travel south to a warmer climate.
In the spring, eagles fly north for many reasons. Some of the best advantages
of migrating north are to do with the available territory, weather and
availability of thermals in the spring. Up north, in Alaska and Northern
Canada, there is much room for eagles to build eyries, start a family,
and to roam through the sky. The weather is neither hot or cold. During
the spring, the temperature usually ranges from cool to warm. The weather
is not too harsh either. These temperatures are most favourable to eagles.
Thermals are most available during the migration time in the spring. This
makes it easier for Bald Eagles to migrate north. According to the Journey
North Migration Map, most Bald Eagles have already made it to British
Columbia, Canada. It is predicted that, between April 11th, and April
18th, the majority of Bald Eagles will have reached their destinations,
some quicker than others, depending on how far their destination may be.
Karen. Bald Eagles, Weigl Educational Publishers, 1998
Ian. Birds of Prey, Wayland Publications, 1990
George. Hawks and Eagles, Smart Apple Media,1998
Aubrey. Eagles, Key Porter Books, 1990
- Lee, Sandra.
Bald Eagles, The Child's World Inc., 1991
Malcolm. The Eagle, Boxtree Limited, 1990
Hope. America's Bald Eagles, P. Putman's Sons, 1985
Mark. The Bald Eagle, Universe Books, 1987
97. Eagles, Microsoft, 1997
- More About
- U.S Climate:
Mystery of Animal Pathfinders