Haliaeetus leucocephalus
A translation of the scientific name of the Bald Eagle
(Haliaeetus leucocephalus) literally means "white-
eaded sea eagle". The Bald Eagle is endemic to North
America, and the national symbol of the United States
of America. Previously classified as an endangered
species under the provisions of the Endangered Species
Act (1973), the Bald Eagle was down-listed or "reduced
in status" from endangered to threatened as of July
1995. Due to the banning of DDT (a dangerous
chlorinated hydrocarbon chemical responsible for
eggshell thinning) from the environment coupled with
significant population gains made by the Bald Eagle
over the last two decades, this bird is expected to be
de-listed or "removed" from the endangered species
list as of the fall of 2000 or the winter of 2001.
Adult Bald Eagles are relatively easy to identify.
They are chocolate brown bodied raptors with a pure
white head and tail, including an unfeathered tarsi
and a massive yellow beak. It typically takes Bald
Eagles 5 years to acquire definitive adult plumage.
Immatures come in a variety of plumages based on age.
Darker-headed, darker breasted birds being of younger
age classes, with 3-4 year old birds being lighter
colored in the head, beak and tail. Adult male Bald
Eagles are smaller than females, weighing 8-9 pounds
compared to 10-14 pound females.
Current population figures indicate there are 26
nesting pairs of Bald Eagles in Yellowstone National
Park, compared to 10 nesting pairs in 1986. And only
14 eaglets fledged in 1999, compared to 10 fledglings
in 1986. Weather continues to play a critical role in
eagle production and most Yellowstone bird production
for that matter, since the Yellowstone Plateau is
notorious for its weather extremes.
Bald Eagle habitat, movements, and food habits change
dramatically from summer to winter. Nesting usually
begins in late February to mid-March. Eagle chicks
hatch from the large platform tree nest in late March-
early April, while fledglings leave the nest somewhere
between late June and late July depending on the
elevation of the nest. In the summer, Bald Eagles are
often found in close association with water, however
they can be found venturing over mountain meadows and
even the summits of mountain peaks on occasion. Their
summertime prey is primarily fish and waterfowl. As
winter approaches, immature and sub-adult eagles
typically leave the park. Research has found many
eagles in these young age classes migrate in a
westerly direction often ending up occupying coastal
and interior winter habitat that ranged from northern
California through Oregon. Some Yellowstone adult Bald
Eagle pairs spend the entire winter in close proximity
to their nesting territory, other pairs migrate to
lower elevations such as the area around Gardiner,
Montana to secure food. Winter habitat for Bald Eagles
often centers around ungulate winter ranges and
watercourses free of ice. Carrion and waterfowl are
the primary food items taken by Bald Eagles in the
winter. Fish can be taken as a winter food item, but
are not as easily available as in the summer due to
the icing of lakes and rivers. By February eagle pairs
return to their nesting territory thus completing a
year in the life of the Yellowstone Bald Eagle.
Grus americana
The scientific name of the Whooping Crane Grus
americana, literally translated means "American
crane". While the Whooping Crane is endemic or native
to North America., it is without question one of the
most endangered and spectacular of the 15 species of
cranes found in the world. The Whooping Crane is
currently classified as an endangered species under
provisions established by the Endangered Species Act
of 1973 and administered by the U.S. Fish and Wildlife Service
Adult Whooping Cranes are easily identified by their
strikingly bold white body plumage, black wingtips,
black facial feather markings, red crown patch, black
legs and feet, yellow-black bi-colored bill, and
yellow eyes. The Whooping Crane is the tallest bird in
North America, standing 5 feet tall, with a wingspan
that measures 7 feet in length. In flight these birds
are quite easy to identify with the bold black and
white plumage, extended neck, and trailing legs. Males
are slightly larger than females both in size
(although difficult to judge) and weight ( males weigh
16 pounds and females 14 pounds).
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