|
In 1965,
the last known pair of bald eagles in New York State built a nest
in an 80-foot shagbark hickory tree at the south end of Hemlock
Lake in Springwater, Livingston County. Constructed from a half-ton
of sticks and twigs, it measured 6 feet across and 7 feet deep.
It was discovered by Tom Rauber, a 42-year-old lineman for Rochester
Telephone Corporation and a lifelong Dansville resident. Over
the next 27 years, the amateur naturalist made nearly 1,400 visits
to observe and photograph the magnificent birds of prey, and witnessed
their continuing failure to hatch an egg. He logged over 52,000
miles to study bald eagle behavior in Alaska, British Columbia,
Florida, Montana and Wyoming. His research was an important contribution
to the eventual recovery of the endangered species.
A beautiful
bird
Bald eagles
are not really bald. They are so called because of their snowy
white head feathers, which they attain at sexual maturity between
4 and 5 years of age. Their tail feathers also turn white, and
their beaks and feet change from gray to yellow. Juveniles are
brown with mottled white feathers, and closely resemble the smaller
golden eagle.
Adopted
as our national symbol in 1782, the bald eagle is a true American
it is only found on this continent. It can live up to 40
years in the wild and longer in captivity. Golden eagles, which
are native to Europe, are circumpolar and are found in Canada
and some western states. A few inhabit the Adirondacks.
Standing
30 inches tall, the bald eagle has a wingspan exceeding 7 feet
and can soar for hours in search of prey, ascending to altitudes
of 10,000 feet or more on thermal air currents. Five of the 24-inch
primary feathers on each wingtip are notched, enabling the eagle
to change its aerodynamics like an aircraft while gliding on shifting
thermals. Its vision is seven times keener than ours, allowing
the bird to easily spot its quarry from high altitudes. And it
can dive at the speed of 65 miles per hour to snatch an unsuspecting
victim with its powerful talons. Weighing between 8 and 12 pounds,
females are 25 to 50 percent larger than males, which is true
for most birds of prey.
Bald eagles
nest in early spring but not as early as the great horned owl,
which may hijack an eagles nest if it gets there first.
Eagles are equally skilled at commandeering heron and osprey nests
and enlarging them to suit their own needs. They will use the
same nest year after year. The nest, or aerie, is built in the
crown of a tall conifer or hardwood tree and is remodeled annually.
Some become enormous, weighing a ton or more, and can collapse
from their own weight. If that happens, the pair will quickly
build another. The hickory tree containing the nest at Hemlock
Lake was toppled by Hurricane Agnes in 1972. The pair constructed
eight different aeries there over the years.
DDT
Bald eagles
have struggled to survive. They mate for life and females lay
one to three eggs in March or early April. The natural mortality
rate among eaglets and fledglings is near 50 percent. For a century,
beginning in the mid-1800s, the raptors were shot as predators
or poached for their feathers, a practice that occurs on occasion
yet today. In 1940, Congress passed the Bald and Golden Eagle
Protection Act, making the capture or killing of any eagle unlawful.
But by the 1950s, they faced a new and more serious threat: chemical
contamination, principally from the pesticide DDT.
After
World War II, DDT was liberally sprayed everywhere to kill blackflies,
mosquitoes and a variety of agricultural and forest insect pests.
It trickled into waterways and became absorbed by waterborne organisms,
insects, amphibians and fish. The bald eagle is primarily a fish
eater, but also devours rodents, snakes, waterfowl and carrion.
In its position at the top of the aquatic food chain, the eagle
accumulated heavy concentrations of DDT with disastrous results
the pesticide weakened its eggshells. Most eggs were broken
by parents during incubation, causing the great birds reproduction
rate to plummet. The Environmental Protection Agency banned DDT
in 1972, and bald eagles were placed under the protection of the
Endangered Species Act in 1973. The population began a slow turnaround.
Tom Rauber
and the experts
When Rauber
reported his discovery to the U.S. Fish and Wildlife Service (USFWS)
in Albany, federal game agent John Waters asked him to monitor
the nest and document his findings. By this time, Rauber had established
a close friendship with bald eagle expert Dr. Dean Amadon, curator
of ornithology at the American Museum of Natural History in New
York. He has since died, but the two men spent several years observing
the remnant pair of eagles as it tried in vain to reproduce. They
suspected DDT poisoning.
In 1972,
at the request of USFWS, Rauber used his linemans climbing
gear to remove an addled egg from the nest for testing. DDT was
confirmed. Amadon hatched a plan to substitute untainted eagle
eggs from Minnesota for the contaminated eggs in the nest. The
ruse had worked with peregrine falcons. He also helped Rauber
secure the federal permit required to handle the birds. Amadon
is credited with conceiving the first effective bald eagle recovery
plan in the United States, using egg transplants.
In 1974,
Rauber received a letter from Gene McCaffrey, the chief of wildlife
for the New York State Department of Environmental Conservation
(DEC). It expressed his intent to initiate a bald eagle recovery
program and asked if Tom would help set it up. With the agencys
superior resources, equipment and staff, Rauber agreed that the
state would indeed be a more effective steward. In 1976, the year
of the U.S. bicentennial, New York became the first state in the
nation to implement a comprehensive bald eagle recovery program
under the voluntary guidance of amateur naturalist, Tom Rauber.
Eagle
recovery techniques have positive results
One of
Raubers first assignments was to show DEC wildlife technician
Mike Allen the ropes. He did exactly that by teaching him how
to climb with linemans gear. The two men built an elevated
blind from which they spent many hours observing and photographing
the two birds. Allen, who still works out of Region 8 headquarters
in Avon, has been with the Endangered Species Unit for more than
30 years. I have been truly blessed to work with bald eagles
for all those years, he said. Even now, when I see
one in flight, I get just as excited as I did back then.
He credits
Rauber with teaching him much of what he knows. Tom is a
good man and we had many good times together, he added.
Albany-based
Endangered Species Unit biologist Peter Nye is one of the nations
foremost bald eagle specialists. He pioneered the DECs eagle
recovery program using three techniques: egg transplants, fostering
and hacking. In fostering, an artificial egg one that wont
break is substituted for a contaminated egg. Remote video
observation of the birds at Hemlock Lake showed that they were
attentive and would make good parents. The eagles accepted and
incubated a synthetic egg as their own, while a newly hatched
eaglet was obtained from a captive breeding facility out of state.
Two weeks later, the artificial egg was replaced with the live
foster chick, which they accepted and reared. For three more years
the pair cared for and fledged captive-bred chicks. After the
male was illegally shot in 1981, the old female mated again and
fostered five more chicks, even after she stopped producing eggs
herself.
A 1976
hacking experiment by DECs Nye at Montezuma National Wildlife
Refuge became the most successful technique. It was the first
program of its kind on the North American continent. Under the
guidance of Cornell University ornithologist Dr. Tom Cade, young
eagles were placed in an artificial nest on an elevated caged
platform several weeks before they could fly. To ensure that their
instinctive fear of humans would not be compromised, they were
discretely fed by hidden caretakers.
When the
eagles were 12 weeks old, the cage was opened to allow the birds
to test their flight capabilities. Over the next nine years, 175
young birds obtained from Alaska were hacked and released from
towers at several locations across the state. By 1989, New Yorks
bald eagle restoration program put itself out of business by achieving
its goal of establishing 10 breeding pairs in the state.
Regional
wildlife manager Larry Myers, retired after 32 years with the
DEC, said, Nobody could have hoped for the success that
has happened. You cant expect not to see an eagle almost
anyplace in the state today. Its the most interesting and
successful project that Ive ever worked on.
Last fall,
I had lunch at the home of Jay and Hannah Zukowski in Webster,
overlooking Irondequoit Bay. I spotted a bald eagle perched in
a tree in their backyard, and when I pointed it out, Jay nonchalantly
responded, Actually, there are two of them. Right
on cue, the second bird joined the first.
Continued
success
The population
continues to rebound. In 1963, there were 417 mating pairs of
bald eagles in the lower 48 states. Today there are nearly 10,000.
The number in New York has grown from a single pair in 1965 to
158 pairs today. The bald eagle was removed from the Endangered
Species List in 2007, but is still protected by other state and
federal laws. DECs Allen is currently monitoring 27 bald
eagle territories in the Finger Lakes Region.
An award-winning
article by Tom Rauber, published in 1976 in The Kingbird magazine,
described his research on the last known pair of bald eagles in
the state. In much the same manner as the man who discovered those
majestic birds, New York state was generous in sharing its experience
in eagle recovery with other states and the Province of Ontario.
Now 84, Tom Rauber is modestly proud of his involvement in helping
to bring the bald eagle back from the brink of extinction, but
is quick to credit DECs Pete Nye, Mike Allen and Larry Myers.
They all say it couldnt have happened without Tom.
John Adamski
is a wildlife photographer, nature writer, sportsman and general
fan of the outdoors. He grew up in Irondequoit, and began taking
pictures when he was the director of fish and wildlife management
at Whitney Park in the Adirondacks. Today he lives in Dansville.
|