ScienCentral News
 
environment general science genetics health and medicine space technology July 10, 2003 
home NOVA News Minutes archive login

is a production of
ScienCentral, Inc.
Making Sense of Science

Also of Interest
Good Fish, Bad Fish (video)

The Core (video)

Ocean Fishing Ban (video)

West Nile Airplanes (video)

Climate Change and Snow (video)

Tsunami Warning (video)

Strong Stuff (video)

Fishing for Trouble (video)

Sinking City (video)

Shifting Seas (video)

Harry Potter’s Owl (video)

Fallout Fears (video)

Cloned Cuisine (video)

Andrew + 10 (video)

Hurricane Heralds (video)

NOVA News Minutes
Visit the NOVA News Minutes archive.
ScienCentral News and Nature
Nature genome promo logo
Don’t miss Enter the Genome
our collaboration with Nature.
Best of the Web!
Popular Science Best of the Web 2000
Selected one of Popular Science’s 50 Best of the Web.
Get Email Updates
Write to us and we will send you an email when a new feature appears on the site.
Eagle Expansion (video)
June 28, 2001

Also on ScienCentral News

Gone Fishing (video) - Using a device that was once part of the problem, biologists are angling for ways to restore fish populations to their old abundance. (6/14/01)

Tipping the Scales - Eating fish may be healthy for you, but eating some kinds of fish may not be healthy for the environment. Some species of fish are so depleted they are now in danger of disappearing from markets and restaurants. (11/9/00)

Running Out of Reptiles - The World’s reptiles could be going the way of the dinosaurs. (8/15/00)

Elsewhere on the web

Listen to a bald eagle courtesy of the American Eagle Foundation.

The Raptor Center at the University of Minnesota rehabilitates injured bald eagles and other birds of prey.

Certify your backyard or workplace as a wildlife habitat with the National Wildlife Federation.

Track the migration of bald eagles and other wildlife.

Eagles Regain a Perch in the Lower 48 - New York Times

San Diego Zoo’s California Condor recovery program

 


As we near Independence Day, images of the bald eagle are becoming more and more prevalent. This serves as an apt metaphor for the last 30 years: Once endangered, the bald eagle’s recovery is described as one of the greatest success stories among endangered species.

As this ScienCentral News video reports, the bald eagle is back. But is it back for good?


An eagle relocation program

The word "hacking" conjures up images of grubby college students trying to break into computer systems they shouldn’t be accessing. But hacking is also the term conservationists use to describe releasing fostered young birds into the wild to populate the surrounding area.

Hacking has proven to be the most successful population recovery technique for the bald eagle, especially in areas where the population was virtually eliminated. The New York State Department of Environmental Conservation began the first North American bald eagle hacking project in 1976, after seeing the state’s bald eagle population plummet from over 70 breeding pairs before 1950 to one unproductive pair in 1960. The New York State Bald Eagle Restoration Project hacked its first pair of eagles June 27th, 1976, at the Montezuma National Wildlife Refuge. The female, Agnes, began breeding in the area in 1980 when she reached maturity at four years old. Agnes’ success heralded the success of the hacking program. The program reached its goal of 10 breeding pairs in 1989, after transplanting 198 nestling eagles from Alaska, Wisconsin, Michigan and Minnesota.

The term is borrowed from the sport of falconry, where trainers use food to teach birds to return to a board (known as a hack) when given their freedom. Similarly, conservationists raise eaglets in a hacking tower, built high above the ground like a typical nest, then release them, hoping they will return to the area where they were once given food to build their own nests.

Hacking towers are enclosed, with at least two sides allowing views of the outside world. Often a lake, source of the birds’ diet of fish, is visible to the young birds. Inside the structure conservationists build a nest just as adult eagles would.

Caretakers feed the birds without making contact so the eagles do not lose their fear of humans or rely on them for food and become unable to hunt in the wild. Sometimes keepers use adult eagle puppets to put food in the cages; sometimes an unmanned trolley enters the cage bearing food.

The youngest birds face a graver danger: If birds younger than 6 weeks sense humans in any way, they identify and "imprint" themselves as human rather than eagle. These eaglets not only will be unable to hunt for food in the wild, but they also will be reluctant to mate with other eagles, effectively sterile.

When the eagles reach about 12 weeks of age, the conservators open the hacking cages and the birds take their first flight, called fledging. Eagles return off and on to the hacking tower for food over the next few weeks, but soon take off to live independently. Often they return to the hacking area to breed, signaling success of the repopulation efforts.

Experts estimate that bald eagles numbered anywhere from 50,000 to 200,000 in the lower 48 states when the Second Continental Congress designated the bald eagle the national symbol in 1782. Due to loss of habitat, hunting, and DDT poisoning, eagle numbers dipped to fewer than 1,000 in the 1960s, when the bird went on the Endangered Species list. While experts disagree on the best way to count the mobile eagles, today eagles probably number at least 20,000, with about 5,000 adult breeding pairs.



by Kathryn Stofer


About Search Login Help Webmaster
ScienCentral News is a production of ScienCentral, Inc.
in collaboration with the Center for Science and the Media.
248 West 35th St., 17th Fl., NY, NY 10001 USA (212) 244-9577.
The contents of these WWW sites © ScienCentral, 2000-2003. All rights reserved.
The views expressed in this website are not necessarily those of the NSF.
NOVA News Minutes and NOVA are registered trademarks of WGBH Educational Foundation and are being used under license.