Little is known about this GoPro video filmed from the back
of an eagle, save that it was filmed in the Mer de Glace area of Chamonix and
that it is the most uplifting thing this writer has seen today.
No explanation necessary really. An enterprising bird owner simply strapped a
camera to an eagle and in doing so allowed us a glimpse into the magic that is
the life of a predatory bird.
Fish Eye Lens
Bald Eagle Facts
Characteristics
Q. Is there any significant reason why bald eagles have
yellow eyes?
A. Great question. I really don't know if there is any
reason that the adult iris is light, except that it is a
morphological difference with the immature birds which
have darker, brown iris' till sexual maturity. Could the
yellow eyes look more threatening?
Q. Does a female bald eagle have a white head like a
male?
A. Yes, they look identical. The female is larger than
the male though, and measurements taken of certain body
parts such as the bill and rear claw (hallux talon) can
distinguish the two sexes; otherwise you can't tell.
Q. How does an eagle see an animals on the ground while
soaring high above?
A. They have extremely keen vision. Their eyes are
specially designed for long distance focus and clarity.
The eye is large with a large retinal surface area with
a high concentration of cones (all of our eyes have rods
and cones which allow us to see) which aid in visual
acuity and color perception, among other features. It
has been estimated that eagles can see 3-4 times farther
than humans and that they can see another eagle soaring
nearly 50 miles away.
Q. What is the bald eagle's diving speed?
A. Pretty fast when they do it, i'd bet 75+mph, although
they seldom really "dive".. They catch prey by flying
low and "snatching with their feet mostly, not like
ospreys or peregrine falcons that actually dive at their
prey.
Q. Can a Bald Eagle swim?
A. Great question. Absolutely. They are very good
swimmers, and i've even seen older nestlings who can't
fly yet swim. It's not uncommon for an eagle to
"misjudge" and latch into a fish too heavy/large for it
to fly with, so they then may swim quite a distance to
shore (wouldn't want to let go of lunch now would we),
drag the fish up on shore and then eat it.
Q. How fast and how far can a bald eagle fly when flying
for 30 minutes?
A. That depends on what the eagle is doing. If it is
just flying from one feeding area to another or from its
nest to the end of the lake say, it probaly flies about
20-30 miles per hour. When migrating, eagles seldom flap
their wings; rather, they use thermal updrafts to gain
great altitude and the saor in a long, descending glide
within which they can hit 50-75 mph easily.
Q. Can an eagle sweat?
A. No. They "thermoregulate" (control their temperature)
by panting with their mouth open or through heat loss
through the unfeathered legs and feet.
Life Cycle
Q. How long does the bald eagle live?
A. Typically in the wild probably between 20-30 years.
Some eagles in captivity have lived up to 50 years, but
in the wild they would not live as long.
Q. How do you determine a bald eagle's age?
A. By plumage until they are 5 years old, then after
that you cannot age them.
Q. Does the bald eagle mate with different kinds of
eagles?
A. No.
Q. Do bald eagles have only one mate for life?
A. Typically, yes, although occasionally an intruding
adult (not one of the pair) comes in (usually a female)
and battles the resident bird for the territory,
sometimes then taking over. If one of the pair dies, the
other will find a new mate and usually keep going in the
same territory.
Q. Do bald eagles build their nests in low trees?
A. No, nor do they prefer to. Given the option, eagles
will choose a "super-canopy" (one rising above the rest)
tree with sturdy limbs and a commanding view of the
surrounding terrain, which is also always very near to
water. Typical nest heights are 50-125 feet high.
Q. How tall do trees half to be for a Bald Eagle to nest
in?
A. The higher the better!
Q. Why do bald eagles have such big nests if they only
have two eggs?
A. They are large birds and their young become quite
large, demanding of lots of space to fit all the birds
and their 6 foot plus wings.
Q. How do eagles find their old nest?
A. Since the nests are so large, it's probably pretty
easy, especially if they haven't gone too far! I suspect
though, that you are asking about birds that migrate
long distances to and from their nests. In that case,
since eagles are diurnal (daytime) fliers, we believe
they use familiar landmarks to guide them to the general
area, and once there, use more familiar and specific
cues to find their particular lake and then the nest
tree. Such cues as extensive mountain ranges or large
water bodies or the coastline might first be used. These
birds obviously "store" great amounts of information or
"memory" of the landscapes in their lives, as they
easily move 50 - 100 miles in a winter day in search of
food.
Q. About how long does it take for the bald eagle's eggs
to hatch and how long until it can fly?
A. It takes 35 days to hatch, then young in nest 10-12
weeks more unti lthey fledge (fly from nest).
Q. How old are they before young eagles can fly?
A. At 10-12 weeks, when they leave their nest.
Q. When do eagles learn to fly and how?
A. At between 10-12 weeks as they first leave the nest
(fledge), and then with more and more practice to and
from the nest and surrounding trees over the next month
or two.
Q. How old does a baby have to be to leave its mother?
A. 10-12 weeks to leave the nest, although fledglings
then often stay around "learning from their parents and
honing their flying and feeding skills for another 1-2
months.
Q. How long does it take the eaglet's feathers to turn
brown?
A. The feathers are brown as soon as they start to
appear, which happens starting at 5 weeks of age; they
are pretty well fully feathered by 9 weeks.
Q. Out of twenty eaglets, how many will live to be
adults?
A. This varies with the population in question. From our
work releasing eagles in New York, about 2.5 adults
would survive for every 20 (1 in 8). Mortality is
highest for eagles in their first year of life,
especially their first six months. The first winter is
crucial. Some biologists (two studies) have estimated
mortality as high as 72 % within one year of fledging
(leaving the nest). Another study estimated that only 11
% of eagles were alive after 3 years of life. In
general, we believe that only about 1 in 10 eagles
survive to adulthood ( 5 yrs of age).
Ecology
Q. How many pounds of food does a Bald Eagle eat in a
day?
A. Approximately .5 - 1.5 per day.
Q. Would an eagle eat other birds? I know that the
eagle's favorite food is fish. I know that sometimes
little birds tease big birds because eagles cannot
maneuver as well as the other birds, so could they eat
them?
A. Very good and accurate observation dale. Yes they do
and will eat other things, although fish are preferred
when they can get them. They also like waterfowl. We
check all of our nests each year when we climb up to
band the eaglets, especially looking for prey (food)
remains. We have found rabbits, muskrats, gulls, ducks,
turtles, and lots of kinds of fish, just to name a few!
Q. What are the eagle's enemies?
A. An occasional Racoon in the nest, or rarely a great
horned owl in the nest (threat to nestlings only), but
otherwise only human beings.
Q. What is the largest prey animal that they have been
known to kill?
A. Good question. The key word here is "kill". Bald
eagles are much more opportunists than killers, meaning
that if they can get an easy meal without expending much
energy (i.e. by killing something) they will do that.
So, reports of bald eagles feeding on deer, whales, or
other large animals, are usually because they found
it/them already dead. Eagles are capable of killing
geese, turkeys, swans (especially if they are already
somewhat debilitated), and large salmon. I would not be
surprised if they took any prey that was under about 3-4
pounds, which would be their max. No type of food item
(meat) would surprise me either, except that obviously
their favored prey is fish.
Q. In what kind of habitats do bald eagles live?
A. Almost exclusively aquatic based habitats, with
forested, generally undisturbed uplands.
Q. How old are Bald Eagles when they migrate?
A. Soon after they leave the nest they begin (sometimes
long distance) wandering--at about 6 months of age.
Q. How do scientists test Bald Eagle's navigational
patterns?
A. We really haven't "tested" their navigational skills,
but have deduced some of their pathways and patterns
from banding and marking numerous birds and then
receiving sightings or recovering dead birds. Also by
affixing both conventional and new satellite radio
telemetry devices to the birds then following their
movements and analyzing where and when they go, deducing
clues from their movements. For example from the
satellite data, it's easy to see if an eagle is
following a water course, where they stop for the night,
etc. See above for more about migration behavior.
Q. Out of all the eagles that migrate, how many make it
to their destinations?
A. Once they become adults, they have a high survival
rate year to year, likely 90% or more.
Q. Do the same eagles come back each year to the same
place?
A. Generally, yes they do, which is why it is so
important to protect those areas eagles are known to
use. You are lucky in maine, as you have a good
population of eagles and some very dedicated biologists
trying to save them. Your department of inland fisheries
and wildlife can give you lots of additional info on
eagles in Maine.
Q. If bald eagles do migrate, do they go to the same
spot every year?
A. Generally (especially with adult birds) the answer is
yes. That is one of the things our research is trying to
answer using satellite tracking
Q. How exactly are satellite transmitters attached to an
eagle?
A. As a "backpack", exactly like the one you might wear
to school. Straps in front of and behind both wings are
stitched together in the front.
Q. Do bald eagles fly in flocks or are they a solitary
bird?
A. They usually fly alone, although some may follow
others to feeding grounds, like from the morning roost,
or when going back to the roost in the late afternoon.
Q. If eagles migrate south for the winter, why do they
bother to go back north? Why don't they just stay in the
south?
A. Great question. They have an inborn tradition to
their general area of fledging, called "fidelity", which
draws them back there. This instinct has probably
evolved over thousands of years because if they were
successfully born in a certain area, the chances of
their success at nesting in the same general area are
probably pretty high. It also helps keep the birds
distributed. If they all decided to stay where they
wintered, things would get pretty crowded in a hurry!
Q. Do bald eagles migrate from summer to winter?
A. Sometimes, especially when they nest in areas far to
the north where these areas freeze over in fall/winter,
so they must leave to find open water and survive. That
is what this study. We think our eagle #32 summers in
Canada and winters in southern New York state. We will
find out as she migrates back to her nesting ground this
spring.
Q. In what areas would bald eagles live in Nebraska?
A. Any areas near large water bodies or rivers with good
fish populations (or waterfowl in the winter),
especially those with little or no human disturbance. I
think that Nebraska has a good number of eagles
wintering there each year, but i'm not sure where--is
the platte river in nebraska?? Check with your state
Fish and Wildlife agency.
Q. Why do Bald eagles only congregate on the West Coast?
A. They don't. They are distributed throughout north
America (except Hawaii). The greatest number of nesting
eagles in the lower 48 states occurs in Florida !!
Q. Can bald eagles be found in every state of the United
States?
A. Yes, except Hawaii.
Q. Can you expain why so many eagles over winter in
Alaska ?
Q. Because of the available habitat up there. Open
water, plentiful food, and undisturbed habitats abound.
Conservation
Q. Is it illegal to possess a bald eagles' feathers? If
so, why?
A. Yes, eagles or any parts, unless you have a special
federal and state permit to do so. The reason is that
many eagles used to be killed for trophies and for their
feet and feathers. Such unregulated killing can threaten
populations of eagles and other species.
Q. If a bald eagle was released from captivity into the
wild, could it survive?
A. That would depend upon how long the eagle had been in
captivity and whether or not it was imprinted to eagles
or to human beings. If one was recovered sick or injured
and held in captivity so it could fully heal, even if
that took up to 2 years, it would still likely be able
to be released and survive.
Q. How did the eagle become the national symbol?
A. On 20 June, 1782, our Continental Congress adopted
the bald eagle as our official national symbol, after
much debate among the members. Thomas Jefferson jokingly
suggested that the wild turkey should be chosen, but
ultimately the symbolic power, strength and freedom
associated with the bald eagle won out.
Q. What might be the reasons for the increase in eagle
numbers?
During the winter months in Southern Ontario, waterfowl
and Christmas Bird counts along the north shore of Lake
Ontario are finding every increasing numbers of bald
eagles.0
A. Bald eagle populations are increasing rangewide, and
have been since about 1980. Reproduction and survival
are both up, since ddt was banned in 1972, humans are
more aware of their actions and what might harm eagles,
and fewer are being shot.
Q. Is it wise or unwise to consider building nesting
platforms for bald eagles? At Presqu'ile Provincial Park
on the north shore of Lake Ontario, sightings of adult
and immature bald eagles are increasing eash year. There
are historical records of bald eagles nesting in the
area many years ago.
A. It is not necessarily premature, and you may well
have eagles attemp to nest in your region within the
next 5-10 years. However, unless you think there is an
absence of suitable nesting trees, you are looking at
quite a bit of work with little chance birds might
accept it. Eagles are prone to accept a platform when
they are already on territory at a given site,
especially when the platform is to bolster or replace a
nest in the same tree or very nearby. But, platforms
seldom simply attract eagles that are not already there;
they prefer to start their own. If you have any super
canopy white pines at all, you mught consider "dressing
up" a crothch to make it hold sticks better, then just
seeding it with a few sticks to look attractive.
Q. Why are Bald Eagles considered the most important
bird in America? They seem to receive lots of attention.
What about smaller species of birds and concern for
their well-being?
A. I don't know if bald eagles are "the most important
bird in America", but you are right that they attract
and receive much attention, likely due to their size and
strength and freedom (see also above on how they were
selected as our symbol). Don't confuse their popularity
with the idea that smaller birds don't get any
attention. The federal government, state governments,
and many private conservation groups spend much time and
money on hundreds of other bird species and even on
invertebrate animal life in need of attention. All of
this is part of our mission to understand and perpetuate
the entire "biodiversity" of our planet, which is
essential if humans are to survive. Contact your state
fish and wildlife agency to ask what other species are
getting attention in your state--you'll be surprised!!!
Q. What's the definition of "game birds"? We have been
having a class discussion about the difference between
the terms - raptors, game birds, endangered birds, etc.
A. "Game birds" get that name from the fact that they
are typically birds that are hunted for sport by humans;
examples are pheasants, grouse, turkeys, woodcock, and
most waterfowl (ducks and geese). Raptors (birds of
prey) are not hunted (legally), except occasionally for
falconry. You folks are not far from some great eagle
watching at the Montezuma national wildlife refuge--you
should check it out!!
Other Questions
Q. Is the age of the bald eagle different than human
years, like dogs?
A. No.
Q. Could you teach a bald eagle to talk and do tricks?
A. No.