The historical plight of bald eagles is told often. At
its lowest point, surveys estimated the bald eagle breeding population was once
as low as 500 nesting pairs in the lower 48 states. Unregulated taking by
humans, loss of habitat and environmental contaminants were main factors in the
eagle’s population decline.
Bald eagles were not protected until Congress passed
the Bald Eagle Protection Act in 1940, because of fears that the nation’s
symbol was threatened with extinction.
While this ended legal indiscriminate killing, other
factors were also working against bald eagles. In the 1950s the pesticide DDT
was widely used to kill insects that were destroying agricultural crops. According
to a fact sheet on the
U.S. Fish and Wildlife Service
website
, DDT and its residues washed into nearby waterways, where aquatic plants
and fish absorbed it.
Bald eagles, in turn, were poisoned with DDT when they
ate the contaminated fish. While the eagles didn’t die from it, the chemical
interfered with the ability of the birds to produce strong eggshells. As a
result, their eggs had shells so thin that they often broke during incubation.
The U.S. Environmental Protection Agency banned the
use of DDT in the United States in 1972, which helped get the bald eagle back
on the road to recovery.
When the bald eagle was listed under the Endangered
Species Act in 1978, North Dakota had no known nesting pairs and hadn’t for
quite some time.
Eventually, the eagle population started to expand and
birds again started to establish nest in July 1999 the USFWS proposed to remove
the bald eagle from the list of threatened and endangered species. In June
2007, the USFWS announced the recovery of the nation’s symbol and removal from
the list of threatened and endangered species.
Through the early years of recovery in North Dakota, the
state Game and Fish Department asked for simple reports of verified bald eagle
sightings. The current bald eagle status no longer warrants reports of individual
sightings, but Game and Fish biologists are still documenting active nests. Eagle nests are now observed
in more than three-quarters of the counties in the state, with the total estimate at around 270.
Here’s a link to report bald eagle nests in North
Dakota:
https://gf.nd.gov/wildlife/nest-reports/bald-eagle
Bald eagles start nest building in January and
February and they may reuse the same nest for many years. They typically lay
1-3 eggs in early to mid-March, and the eggs hatch in about 35 days.
By early July, the young will be nearly the same size
as the adults and will venture out onto the branches in the nest tree and take
their first unsteady flights. By the end of July or early August, the young are
fully capable of flying and will leave (fledge) the nest.
However, the fledglings may remain in the general area
of the nest and the adults may still feed them for up to six weeks.
