I don’t know of a live native bird that excites people more,
who are seeing it for the first time, than our national bird, the
bald eagle. The first one I saw when I was a child was a captive
bird in the Lincoln Park Zoo in Chicago, but even that one
excited my parents, two older brothers and me.
It wasn’t until I got out of the army in 1955 and began
teaching at Shorewood Hills School in Madison that we’d often
see them wintering and catching stunned fish below the dam along
the Wisconsin River in the Sauk City area. My high count during
January of 1960 from one point on the bridge along State Highway
21 just below the Petenwell dam, east of Necedah, was 27. Those
were northern eagles that apparently had not yet been affected
by the pesticide content in their fish prey, especially DDT,
that so profoundly lowered the nesting population of bald eagles
in most of the lower 48 states.
My friend, Tom Erdman of Green Bay, joined me during the last
weekend of March 1969 to scour the north shore area of Mud Bay
(also called Moonlight Bay) for a potential bald eagle nest.
Reports from various people at that time tended to indicate that
eagles had not nested along the east side of the Door Peninsula
for close to 20 years. However, occasional reports of a bald
eagle in that general area was enough to excite us into thinking
that a pair may still be holding strong in some unknown secluded
nesting area, perhaps somewhere between Jacksonport and Baileys
Harbor. Much to our disappointment we found no nest that
weekend.
The American bald eagle is usually beginning to nest in
Wisconsin by the third or fourth week of March. Much like the
owls, the young eagles require a rather long period of time to
develop enough size, strength and flight feathers, decidedly
different from the small songbirds that will be flying within
three weeks or sooner after hatching.
There was ongoing intensified interest at that time in the
bald eagles, ospreys and peregrine falcons of the Midwest.
Research was pointing toward the possibility of the fast
approaching extinction of all of those birds. Scientific studies
found that a build-up of especially DDT and other similar
pesticides in the fatty tissue of the nesting females was greatly
upsetting their calcium metabolism to the extent that the eggs,
having around 25% thinner shells, were not supporting the weight
of the incubating birds and were cracking.
What kept running through the minds of Tom and me on that
fruitless search for nests in March of 1969 was the claim being
made by the experts that, as a breeding bird it would remain only
as a memory for a few, and just a dream for the rest of us.
Finally the tide turned, the waters began clearing up once the
use of DDT was banned nationwide, and what genuinely thrilled
many people of our area by the late 1980’s was the documentation
of the first pair of bald eagles to successfully nest and raise
young in Door County after a lapse of over 35 years. Today a
reasonable estimate is that at least seven to eight pairs of
these majestic birds are nesting on the peninsula. Now hardly a
week goes by, year-round, that someone doesn’t excitedly call
about seeing a bald eagle in the region.
Occasionally someone reports seeing a golden eagle, a
predominantly western-nesting bird. It is not entirely
impossible although it is quite improbable. Occasional Wisconsin
sightings are being made every year. Tom Erdman, who keeps
careful track of birds of prey, especially along the west shore
of Green Bay, sees a few each fall during his hawk and owl
banding operations there.
What’s more likely is that people are seeing a first-year bald
eagle which, outwardly, can resemble a golden eagle quite
closely. Both are very dark. There are several features of the
bald and golden eagles to look for that may help in their
identification. Wingspan of the bald can be between 82 and 97
inches while that of the golden is between 72 and 87. Length of
the bald ranges between 30-36 inches while that of the golden is
between 27-33 inches. Clearly there is overlapping of wingspans
and lengths in comparing the bald to the golden.
Close looks at soaring eagles can also be very helpful in
telling the two species apart. The bald eagle soars with its
wings held very flat. Frequently a golden will soar with its
wings held at a slight dihedral – somewhat upward. Occasionally
the golden will also soar with its wings held quite straight,
much like a bald eagle, so unfortunately this habit, while
important to observe, may not be a good diagnostic feature all of
the time.
A golden eagle’s head while the bird is in flight is known to
project less than one half the length of its tail. The head of a
bald eagle projects more than half the length of its tail.
According to the excellent Peterson Field Guide,
Hawks, by
William S. Clark and Brian K. Wheeler, "The trailing edge of
the wing (of the bald eagle) is straighter and less pinched in at
the body than that of the golden eagle." Surely you are
beginning to see that there is much of interest to study in the
plumage and manner of flight of eagles as well as other raptors.
We all should be thankful and rejoice that our national bird,
the American bald eagle, has made such a remarkable comeback in
its population in North America. Our next sighting of one of
these beautiful majestic creatures will be just as exciting as
was the first.
This permanently injured 2-year-old bald eagle shows its dark plumage.
The head and tail feathers will not turn white until its fourth year. The eagle is a resident at
Milwaukee's Schlitz Audubon Nature Center and is a part of its education program.
This column appeared in the Door County Advocate
on 04/03/2004.
© Copyright 2004 Roy Lukes. All rights reserved.
