With three new eagles living at Radnor Lake State Park’s Barbara J. Mapp Aviary Education Center, knowing more about bald eagles may make the viewing of these majestic birds more interesting.
Here are 12 things to know about bald eagles:
1. The Continental Congress declared the bald eagle our national symbol on June 20, 1782. Benjamin Franklin preferred the turkey.
2. The bald eagle’s name origin is an old English word “balde,” meaning white, as in “white headed eagle.”
3. It’s diet is 70-90% fish, live or freshly dead. They also feed on rabbits, coots and injured waterfowl. The eagles at Radnor eat mostly rats, quail and trout.
4. Male bald eagles’ weight may range from 6-9 pounds, with females’ weights usually 20-30% more. An eagle’s wingspan varies from 6-8 feet.
5. Eagles normally mate for life. Sexual maturity occurs at 4-6 years of age. The heads and tails then change from dark brown to white. The beaks change from black to yellow.
6. Bald eagle’s life span has been recorded at 39 years in the wild and 50 years in captivity.
7. Nest diameter averages five feet during the first year. The same eagles may add to the nest each year, up to a size of eight feet across and 12 feet deep.
8. Young eagles normally leave the nest at 10-12 weeks of age.
9. Horizontal flight speed has been measured at up to 44 miles per hour. They can dive at speeds up to 100 miles per hour.
10. The bald eagle came close to extinction. But due largely to the banning of DDT insecticide in the U.S. in 1972, and restoration efforts since 1976, nests in the lower 48 states have increased dramatically. In 2007, eagles were removed from the “threatened” list of endangered species.
11. The term “eagle eye” refers to the eagle’s amazing eyesight, maybe which is 4-8 times stronger than that of the average human. An eagle is said to be able to spot prey as far as two miles away.
12. “Despite all the efforts made to protect them, 68% of bald eagle deaths are still caused by humans. Scientists found that 23% of eagles died when they hit man-made objects like wires, cars, and buildings, while a further 22% died after being shot. Another 5% died after they were trapped, 9% from being electrocuted, and 11% after they had been poisoned.