Blank Park Zoo
Blank Park Zoo

Open 10 a.m. – 4 p.m.
Admission: $14 Adult | $8 Child

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Open 10 a.m. – 4 p.m.
Admission: $14 Adult | $8 Child

View All Rates ›
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The Majestic Bird

Raptor Resource Project

The Bald Eagle, which is found exclusively in North America, has a wingspan of 6-8 feet and weighs 8-15 pounds, although females can be slightly larger than males. Their eyesight is 4-8 times stronger than a human’s. They often live to be 15-25 years old in the wild. When they fly, eagles can average speeds of 30mph, and soar with the help of thermals (rising currents of warm air). Bald Eagles start to get their distinctive white head and brown body color after about five years, and may start breeding at about the same age.

Eagle Parents

Raptor Resource Project

To show interest in each other, courting Bald Eagles exhibit many behaviors like swooping flights and dives; soaring together, beak kissing, and more. To further strengthen their bond, eagles build nests together and communicate through a range of vocalizations, including calls and chatters. Generally, eagles are monogamous, staying together throughout their lives.

Young Eaglets

Raptor Resource Project

In the Midwest, Bald Eagles typically mate in February - March, after which up to 3 eggs are laid, 3-4 days apart and incubated for just over one month. These eggs weigh just a few ounces and are about the size of a tennis ball.  Both the male and female take turns sitting on the eggs to keep them warm. The parents also rotate the egg every 1-2 hours to make sure they are at optimal temperature and humidity. Bald Eagle eggs hatch in the order they were laid, doing so every 3 days.

Raptor Resource Project

Eggs and young eaglets rely on their parents for warmth and food. Prolonged absence of parents can result in eggs not hatching or the death of the young. Human presence can have a negative effect on the eagle family. If the parents are interrupted while hunting, they may not be able to bring food back for the eaglets. Also, if nesting is interrupted by some kind of disturbance, eagles don’t attempt to re-nest until the following year. About 10-14 weeks after hatching, eaglets take their first flight and leave the nest a few days after that.

Bald Eagle Homes

Bald Eagles usually live near water with an abundant food supply. They make their nests in mature or dead trees. Nests, sometimes weighing more than 1,000 pounds, are made with large sticks and lined with moss, leaves, grass, sod, plant stalks and more. These nests are typically 4-6 feet wide and about 3 feet deep, although larger nests exist. Eagle pairs will return to the same nesting site each year. If their original nest is no longer there, they will re-build, often times in a tree right “next door.”

Bald Eagle Migration

In late October and November, food begins to be scarce in their northern range, signaling most eagles to migrate to their winter hunting grounds in the lower 48 states. These wintering sites are usually along open water where eagles can hunt for fish and waterfowl. Eagles also scavenge in nearby terrestrial habitats, eating carrion.

A Troubled Past & Triumphant Recovery

Jim McConnell Photograph

As western expansion and conversion of land to agriculture increased in the 1800s, the eagle population began its decline. Pressure on Bald Eagles included hunting for their feathers and habitat loss. Even though eagles can only carry 3-5 pounds, common misconceptions of the time led to many being shot due to a fear of eagles carrying away small children and livestock.

As agricultural production increased in the mid-1900s, the development and wide use of pesticides began to seriously affect eagles and other wildlife. Dichlorodiphenyltrichloroethane, or more commonly known as DDT, was developed in the 1940s. After application, it often washed into natural water systems, contaminating the food supply and affecting reproduction rates by thinning the shells of eagle eggs.

Raptor Resource Project

The Environmental Protection Agency (EPA) banned the use of DDT in 1972. A few years later, Bald Eagles were listed as endangered or threatened under the Endangered Species Act in the lower 48 states. These measures helped Bald Eagle numbers rise by thousands. In 2007, it was determined that the species had recovered enough to be removed from the Endangered Species List.

 

Raptor Resource Project

 

Bald Eagle Recovery in Iowa

There was no known Bald Eagle nesting pairs in the state of Iowa after 1905. It wasn’t until 1977 that eagles had returned to Iowa. Today, Bald Eagles can be found in all of Iowa’s 99 counties. About one-third of the entire global Bald Eagle population overwinters in Iowa, Illinois and Missouri.

Bald Eagle numbers in Iowa will continue to grow with help from people like you!


For more information:

http://www.iowadnr.gov/Conservation/Iowas-Wildlife/Bald-Eagles

http://www.iucnredlist.org/details/22695144/0

https://www.fws.gov/Midwest/eagle/conservation/baea_nhstry_snstvty.html

http://www.raptorresource.org/2016/02/14/courtship-copulation-and-egg-creation/

https://www.epa.gov/ingredients-used-pesticide-products/ddt-brief-history-and-status

https://www.raptorresource.org/learning-tools/dealing-with-dead-or-injured-bald-eagles-and-other-birds-of-prey/

https://energy.gov/eere/wind/advantages-and-challenges-wind-energy

http://www.iowadnr.gov/Conservation/Wildlife-Stewardship/Non-Game-Wildlife/Conservation/Wind-and-Wildlife

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