
The bald eagle (Haliaeetus leucocephalus, from Greek hali- = sea, aiētos = eagle, leuco- = white, cephalos = head) is a bird of prey found in North America. A sea eagle, it has two known sub-species and forms a species pair with the white-tailed eagle (Haliaeetus albicilla). Its range includes most of Canada and Alaska, all of the contiguous United States,
and northern Mexico. It is found near large bodies of open water with
an abundant food supply and old-growth trees for nesting.

The bald eagle is an opportunistic feeder which subsists mainly on fish, which it swoops down and snatches from the water with its talons. It builds the largest nest
of any North American bird and the largest tree nests ever recorded for
any animal species, up to 4 m (13 ft) deep, 2.5 m (8.2 ft) wide, and 1

metric ton (1.1 short tons) in weight.[2] Sexual maturity is attained at the age of four to five years.
Bald eagles are not actually bald;
the name derives from an older meaning of "white headed". The adult is
mainly brown with a white head and tail. The sexes are identical in plumage, but females are about 25 percent larger than males. The beak is large and hooked. The plumage of the immature is brown.

The bald eagle is both the national bird and national animal of the United States of America. The bald eagle appears on its Seal. In the late 20th century it was on the brink of extirpation in the continental United States. Populations recovered and the species was removed from the U.S. federal government's list of endangered species on July 12, 1995 and transferred to the list of threatened species. It was removed from the List of Endangered and Threatened Wildlife in the Lower 48 States on June 28, 2007.

The plumage
of an adult bald eagle is evenly dark brown with a white head and tail.
The tail is moderately long and slightly wedge-shaped. Males and
females are identical in plumage coloration, but sexual dimorphism is evident in the species, in that females are 25% larger than males.[2] The beak, feet and irises
are bright yellow. The legs are feather-free, and the toes are short
and powerful with large talons. The highly developed talon of the hind
toe is used to pierce the vital areas of prey while it is held

immobile
by the front toes.[3] The beak is large and hooked, with a yellow cere.[4] The adult bald eagle is unmistakable in its native range. The closely related African fish eagle (H. vocifer)
(from far outside the bald eagle's range) also has a brown body, white
head and tail, but differs from the bald in having a white chest and
black tip to the bill.[5] 
The plumage of the immature is a dark brown overlaid with messy white
streaking until the fifth (rarely fourth, very rarely third) year, when
it reaches sexual maturity.[2][3] Immature bald eagles are distinguishable from the golden eagle (Aquila chrysaetos),
the only other very large, non-vulturine bird in North America, in that
the former has a larger, more protruding head with a larger beak,
straighter edged wings which are held flat (not slightly raised) and
with a stiffer wing beat and feathers which do not completely cover the
legs. When seen well, the golden eagle is distinctive in plumage with a
more solid

warm brown color than an immature bald eagle, with a
reddish-golden patch to its nape and (in immature birds) a highly
contrasting set of white squares on the wing.[6]
Another distinguishing feature of the immature bald eagle over the
mature bird is its black, yellow-tipped beak; the mature eagle has a
fully yellow beak.

The bald eagle has sometimes been considered the largest true raptor (accipitrid) in North America. The only larger species of raptor-like bird is the California condor (Gymnogyps californianus), a New World vulture which today is not generally considered a taxonomic ally of true accipitrids.[7] However, the golden eagle, averaging 4.18 kg (9.2 lb) and 63 cm (25 in) in wing chord length in its American race (A. c. canadensis),
is merely 455 g (1.003 lb) lighter in mean body mass and exceeds the
bald eagle in mean wing chord length by around 3 cm (1.2 in).[5][8] Additionally, the bald eagle's close cousins, the relatively longer-winged but shorter-tailed white-tailed eagle and the overall larger Steller's sea eagle (H. pelagicus), may, rarely, wander to coastal Alaska from Asia.[5]
The bald eagle has a body length of 70–102 cm (28–40 in). Typical
wingspan is between 1.8 and 2.3 m (5.9 and 7.5 ft) and mass is normally
between 3 and 6.3 kg (6.6 and 13.9 lb).[5] Females are about 25% larger than males, averaging 5.6 kg (12 lb), and against the males' average weight of 4.1 kg (9.0 lb).[2][9][10][11] The size of the bird varies by location and generally corresponds with Bergmann's rule, since the species increases in size further away from the Equator and the tropics. The smallest specimens are those

from Florida, where mature males may weigh as little as 2.3 kg (5.1 lb) and have a wingspan of 1.68 m (5.5 ft)[citation needed]. Similarly small, eagles from South Carolina average 3.27 kg (7.2 lb) in mass and 1.88 m (6.2 ft) in wingspan.[12] The largest eagles are from Alaska, where large females may weigh up to 7.5 kg (17 lb) and span 2.44 m (8.0 ft) across the wings.[4][13] A survey of adult weights in Alaska showed

that females weighed on average 6.3 kg (14 lb) and males weighed 4.3 kg (9.5 lb).[14] Among standard linear measurements, the wing chord is 51.5–69 cm (20.3–27.2 in), the tail is 23–37 cm (9.1–14.6 in) long, and the tarsus is 8 to 11 cm (3.1 to 4.3 in).[5][15] The culmen reportedly ranges from 3 to 7.5 cm (1.2 to

3.0 in), while the measurement from the gape to the tip of the bill is 7–9 cm (2.8–3.5 in).[15][16]
The call consists of weak staccato, chirping whistles, kleek kik ik ik ik, somewhat similar in cadence to a gull's call. The calls of young birds tend to be more harsh and shrill than those of adults.[5][6]

The bald eagle placed in the genus Haliaeetus (sea eagles) which gets both its common and specific scientific names from the distinctive appearance of the adult's head. Bald in the English name is derived from the word piebald, and refers to the white head and tail feathers and their contrast with the darker body.[17] The scientific name is derived from Haliaeetus, New Latin for "sea eagle" (from the Ancient

Greek haliaetos), and leucocephalus, Latinized Ancient Greek for "white head," from λευκος leukos ("white") and κεφαλη kephale ("head").[18][19]
The bald eagle was one of the many species originally described by Linnaeus in his 18th century work Systema Naturae, under the name Falco leucocephalus.[20]
There are two recognized subspecies of bald eagle:[2][21]

The bald eagle forms a species pair with the Eurasian
white-tailed eagle. This species pair consists of a white-headed and a
tan-headed species of roughly equal size; the white-tailed eagle also
has overall somewhat paler brown body plumage. The two species fill the
same ecological niche in their respective

ranges. The pair diverged from other sea eagles at the beginning of the Early Miocene (c. 10 Ma BP) at the latest, but possibly as early as the Early/Middle Oligocene, 28 Ma BP, if the most ancient fossil record is correctly assigned to this genus.[24] The two species probably diverged in the North Pacific, as the white-tailed eagle spread westwards into Eurasia and the bald eagle spread eastwards into North America.[25][not in citation given]

The bald eagle's natural range covers most of North America, including most of Canada, all of the continental United States, and northern Mexico. It is the only sea eagle endemic to North America. Occupying varied habitats from the bayous of Louisiana to the Sonoran Desert and the eastern deciduous forests of Quebec and New England, northern birds are migratory,
while southern birds are resident, remaining on their breeding
territory all year. At minimum population, in the 1950s, it was largely

restricted to Alaska, the Aleutian Islands, northern and eastern Canada, and Florida.[26]
Today, they are much more common (almost attaining their peak numbers
pre-colonization in North America), and nest in every continental state
and province in the United States and Canada.[27]
Bald Eagles will also congregate in certain locations in winter. From
November until February, one to two

thousand birds winter in Squamish, British Columbia, about halfway between Vancouver and Whistler. The birds primarily gather along the Squamish and Cheakamus Rivers, attracted by the salmon spawning in the area.[28]

It has occurred as a vagrant twice in Ireland; a juvenile was shot illegally in Fermanagh on January 11, 1973 (misidentified at first as a white-tailed eagle), and an exhausted juvenile was captured in Kerry on November 15, 1987.[29]

The bald eagle occurs during its breeding season in virtually any kind of American
wetland habitat such as
seacoasts,
rivers, large
lakes or
marshes
or other large bodies of open water with an abundance of fish. Studies
have shown a preference for bodies of water with a circumference greater
than 11 km (7 mi), and lakes with an area greater than 10 km
2 (4 sq mi) are optimal for breeding bald eagles.
[30]
The bald eagle typically requires old-growth and mature stands of
coniferous or
hardwood
trees for perching, roosting, and nesting. Tree species reportedly is
less important to the eagle pair than the tree'
breeding bald eagles.
[30]
The bald eagle typically requires old-growth and mature stands of coniferous or hardwood
trees for perching, roosting, and nesting. Tree species reportedly is
less important to the eagle pair than the tree's height, composition and
location.[31]
Perhaps of paramount importance for this species is an abundance of
comparatively large trees surrounding the body of water. Selected trees
must have good visibility, be over 20 m (66 ft) tall, an open structure,
and proximity to prey. If nesting trees are in standing water such as
in

a mangrove swamp, the nest can be located fairly low, at as low 6 m
(20 ft) above the ground.[32] In a more typical tree standing on dry ground, nests may be located from 16 to 38 m (52 to 125 ft) in height. In Chesapeake Bay,
nesting trees averaged 82 cm (32 in) in diameter and 28 m (92 ft) in
total height, while in Florida, the average nesting tree stands 23 m
(75 ft) high and is 23 cm (9.1 in) in diameter.[33][34] Trees used for nesting in the Greater Yellowstone area average 27 m (89 ft) high.[35]
Trees or forest used for nesting should have a canopy cover of no more
than 60%, and no less than 20%, and be in close proximity to water.[30]
Most nests have been found within 200 m (660 ft) of open water. The
greatest distance from open water recorded for a bald eagle nest was
over 3 km (1.9 mi), in Florida.[7]
Bald eagle nests are often very large in order to compensate for size
of the birds. The largest recorded nest was found in Florida in 1963,
and was measured at nearly 10 feet wide and 20 feet deep.[36]
In Florida, nesting habitats often consist of mangrove swamps, the shorelines of lakes and rivers, pinelands, seasonally flooded flatwoods, hardwood swamps, and open prairies and pastureland with

scattered tall trees. Favored nesting trees in Florida are slash pines (Pinus elliottii), longleaf pines (P. palustris), loblolly pines (P. taeda) and cypress trees, but for the southern coastal areas where mangroves are usually used.[32] In Wyoming, groves of mature cottonwoods
or tall pines found along streams and

rivers are typical bald eagle
nesting habitats. Wyoming eagles may inhabit habitat types ranging from
large, old-growth stands of ponderosa pines (Pinus ponderosa) to narrow strips of riparian trees surrounded by rangeland.[7] In Southeast Alaska, Sitka spruce (Picea sitchensis) provided 78% of the nesting trees used by eagles, followed by hemlocks (Tsuga) at 20%.[31] Increasingly, eagles nest in man-made reservoirs stocked with fish.[32]
The bald eagle is usually quite sensitive to human activity while
nesting, and is found most commonly in areas with minimal human
disturbance. It chooses sites more than 1.2 km (0.75 mi) from
low-density human disturbance and more than 1.8 km (1.1 mi) from medium-
to high-density human disturbance.[30]
However, bald eagles will occasionally venture into large estuaries or
secluded groves within major cities, such as Hardtack Island on the Willamette River in Portland, Oregon or John Heinz National Wildlife Refuge at Tinicum in Philadelphia, Pennsylvania, which are surrounded by a great quantity of human activity.[37][38] Even more contrary to the usual sensitivity to disturbance, a family of bald eagles moved

to the Harlem neighborhood in New York City in 2010.[39]
While wintering, bald eagles tend to be less habitat and disturbance
sensitive. They will commonly congregate at spots with plentiful perches
and waters with plentiful prey and (in Northern climes) partially
unfrozen waters. Alternately, non-breeding or wintering bald eagles,
particularly in areas with a lack of human disturbance, spend their time
in various upland, terrestrial habitats sometimes quite far away from
waterways. In the northern half of North America (especially the
interior portion), this terrestrial inhabitance by bald eagles tends to
be especially prevalent because unfrozen water may not be accessible.
Upland wintering habitats often consist of open habitats with
concentrations of medium-sized mammals, such as prairies, meadows or tundra, or open forests with regular carrion access.[7][31]

The bald eagle is a powerful flier, and soars on thermal convection currents. It reaches speeds of 56–70 km/h (35–43 mph) when gliding and flapping, and about 48 km/h (30 mph) while carrying fish.[40] Its dive speed is between 120–160 km/h (75–99 mph), though it seldom dives vertically.[41]
It is partially migratory, depending on location. If its territory has
access to open water, it remains there year-round, but
if the body of
water freezes during the winter, making it impossible to obtain food, it
migrates to the south or to the coast. A number of populations are
subject to post-breeding dispersal, mainly in juveniles; Florida eagles,
for example, will disperse northwards in the summer.[42] The bald eagle selects migration

routes which take advantage of thermals, updrafts,
and food resources. During migration, it may ascend in a thermal and
then glide down, or may ascend in updrafts created by the wind against a
cliff or other terrain. Migration generally takes place during the
daytime, usually between the local hours of 8:00 a.m. and 6:00 p.m.,
when thermals are produced by the sun.[3]

The bald eagle is an opportunistic carnivore with the capacity to predate a great variety of prey. Throughout their range, fish often comprise the majority of the eagle's diet.[43]
In 20 food habit studies across the species' range, fish comprised 56%
of the diet of nesting eagles, birds 28%, mammals 14% and other prey 2%.[44] In Southeast Alaska, fish comprise approximately 66% of the year-around diet of bald eagles and 78% of the prey brought to the nest by the parents.[45] Eagles living in the Columbia River Estuary in Oregon were found to rely on fish for 90% of their dietary intake.[46] In the Pacific Northwest,

spawning trout and salmon provide most of the bald eagles' diet from late summer throughout fall.[47] Southeast Alaskan eagles largely predate pink salmon (Oncorhynchus gorbuscha), coho salmon (O. kisutch) and, more locally, sockeye salmon (O. nerka), with chinook salmon (O. tshawytscha), due to their large size (12 to 18 kg (26 to 40 lb) average adult size) probably being taken only as carrion.[45] Also important in the estuaries and shallow coastlines of southern Alaska are Pacific herring (Clupea pallasii), Pacific sand lance (Ammodytes hexapterus) and eulachon (Thaleichthys pacificus).[45] In Oregon'
Estuary in
Oregon were found to rely on fish for 90% of their dietary intake.
[46] In the
Pacific Northwest, spawning
trout and
salmon provide most of the bald eagles' diet from late summer throughout fall.
[47] Southeast Alaskan eagles largely predate
pink salmon (
Oncorhynchus gorbuscha),
coho salmon (
O. kisutch) and, more locally,
sockeye salmon (
O. nerka), with
chinook salmon (
O. tshawytscha), due to their large size (12 to 18 kg (26 to 40 lb) average adult size) probably being taken only as carrion.
[45] Also important in the estuaries and shallow coastlines of southern Alaska are
Pacific herring (
Clupea pallasii),
Pacific sand lance (Ammodytes hexapterus) and eulachon (Thaleichthys pacificus).[45] In Oregon's Columbia River Estuary, the most significant prey species were largescale suckers (Catostomus macrocheilus) (17.3% of the prey selected there), American shad (Alosa sapidissima; 13%) and common carp (Cyprinus carpio; 10.8%).[46] Eagles living in the Chesapeake Bay in Maryland were found to subsist largely on American gizzard shad (Dorosoma cepedianum), threadfin shad (D. petenense) and white bass

(Morone chrysops).[48] Floridian eagles have been reported to predate catfish, mostly prevalently the brown bullhead (Ameiurus nebulosus) and any species in the Ictalurus genus as well as mullet, trout, needlefish, and eels.[7][32][49] Wintering eagles on the Platte River in Nebraska preyed mainly on American gizzard shads and common carp.[50]
From observation in the Columbia River, 58% of the fish were caught
directly by the predating eagle, 24% were scavenged as carcasses and 18%
were pirated away from other animals.[46]

Even eagles living in relatively arid regions still typically rely primarily on fish as prey. In Sonora, Mexico and Arizona, 77% and over 73%, respectively, of prey remains at the nests were from fish, largely various catfish and rainbow trout (Oncorhynchus mykiss).
Prey fish targeted by bald eagles are often quite large. When
experimenters offered fish of different sizes in the breeding season
around Lake Britton in California,
fish measuring 34 to 38 cm (13 to 15 in) were taken 71.8% of the time
by parent eagles while fish measuring 23 to 27.5 cm (9.1 to 10.8 in)
were chosen only 25% of the time.[51] At nests around Lake

Superior, the remains of fish (mostly suckers) were found to average 35.4 cm (13.9 in) in total length.[52]
In the Columbia River estuary, most predated by eagles were estimated
to measure between 30 and 60 cm (12 and 24 in) in length, and carp flown
with (laboriously) were up to 86 cm (34 in) in length.[46]

Benthic fishes
such as catfish are usually consumed after they die and float to the
surface, though while temporarily swimming in the open may be more
vulnerable to predation than most fish since their eyes focus downwards.[48] Bald eagles also regularly exploit water turbines which produce battered, stunned or dead fish easily consumed.[53] Predators who leave behind scraps of dead fish that they kill, such as brown

bears (Ursus arctos), gray wolves (Canis lupus) and red foxes (Vulpes vulpes), may be habitually followed in order to scavenge the kills secondarily.[45] Once North Pacific salmon die off after spawning, usually local bald eagles eat salmon carcasses almost exclusively. Eagles in Washington
need to consume 489 g (1.078 lb) of fish each day for survival, with
adults generally consuming more than juveniles and thus

reducing
potential energy deficiency and increasing survival during winter.[44]
Behind fish, the next most significant prey base for bald eagles are other waterbirds.
The contribution of such birds to the eagle's diet is variable,
depending on the quantity and availability of fish near the water's
surface. Waterbirds can seasonally comprise from 7% to 80% of the prey
selection for eagles in certain localities.[46][54] Exceptionally, in the Greater Yellowstone area, birds were eaten as regularly as fish year-

around, with both prey groups comprising 43% of the studied dietary intake.[35] Preferred avian prey includes grebes, alcids, ducks, gulls, coots, herons, egrets, and geese.[55] Bird species most preferred as prey by eagles tend to be medium-sized, such as western grebes (Aechmophorus occidentalis), mallards (Anas platyrhynchos) and American coots (Fulica americana) as such prey is relatively easy for the much
larger eagles to catch and fly with.[7][46] American herring gull (Larus smithsonianus) are the favored avian prey species for eagles living around Lake Superior.[52] Larger waterbirds are occasionally predated as well, with wintering emperor geese (Chen canagica) and snow geese (C. caerulescens), which gather in large groups, sometimes becoming regular prey.[15][56] Other large waterbirds hunted at least occasionally
by bald eagles have included common loons (Gavis immer),[57] great black-backed gulls (Larus marinus),[58] sandhill cranes (Grus canadensis),[59] great blue herons (Ardea herodias),[44] Canada geese (Branta canadensis),[48] brown pelicans (Pelecanus occidentalis),[32] and fledging American white pelicans (P. erythrorhynchos).[60] Colony nesting seabirds, such as alcids, storm petrels, cormorants, northern gannets (Morus bassanus), terns and gulls,
may be especially vulnerable to predation. Due to easy accessibility
and lack of formidable nest defense by such species, bald eagles are
capable of predating such seabirds at

all ages, from eggs to mature
adults, and can effectively cull large portions of a colony.[61]
Along some portions of the North Pacific coastline, bald eagles which had historically predated mainly kelp-dwelling fish and supplementally sea otter (Enhydra lutris)
pups are now preying mainly on seabird colonies since both the fish
(possibly due to overfishing) and otters (cause unknown) have had
precipitious

population declines, causing concern for seabird
conservation.[62] Because of this more extensive predation, some biologist have expressed concern that murres are heading for a "conservation collision" due to heavy eagle predation.[61] Eagles have been confirmed to attack nocturnally active, burrow-nesting seabird species such as storm petrels and shearwaters by digging out their burrows and feeding on all animals they find inside.[63]
If a bald eagle flies close by, waterbirds will often fly away en
masse, though in other cases they may seemingly ignore a perched eagle.
If the said birds are on a colony, this exposed their unprotected eggs
and nestlings to scavengers such as gulls.[61] Bird prey may occasionally be

attacked in flight, with prey up to the size of Canada geese attacked and killed in mid-air.[55] Unprecedented photographs of a bald eagle unsuccessfully attempting to predate a much larger adult trumpeter swan (Cygnus buccinator) in mid-flight were taken recently.[64]
While adults often actively predate waterbirds, congregated wintering
waterfowl are frequently exploited for carcasses to scavenge by
immature
eagles in harsh winter weather.[65] Bald eagles have been recorded as killing other raptors on occasion. In some cases, these may be attacks of competition or kleptoparasitism
on rival species but ended with the consumption of the victim.
Raptorial birds reported to have be hunted by these eagles have included
large adults of species such as great horned owls (Bubo virginianus),[66] red-tailed hawks (Buteo

jamaicensis),[67] ospreys (Pandion haliaetus)[68] and black (Coragyps atratus) and turkey vultures (Cathartes aura).[69]
Mammalian prey includes rabbits, hares, ground squirrels, raccoons (Procyon lotor), muskrats (Ondatra zibethicus), beavers (Castor canadensis), and deer
fawns. Newborn, dead, sickly or already injured mammals are often
targeted. However, more formidable prey such as adult raccoons and
sub-adult beavers are sometimes attacked. In the Chesapeake Bay area, bald eagles are reportedly the main natural predators of raccoons.[70][71] Where available, seal colonies can provide much food. On Protection Island, Washington, commonly feed on harbor seal (Phoca vitulina) afterbirths, still-borns and sickly seal pups.
[72] On San Juan Island in Washington, introduced European rabbits (Oryctolagus cuniculus), mainly those killed by auto accidents, comprise nearly 60% of the dietary intake of eagles.[73]
In landlocked areas of North America, wintering bald eagles may become
habitual predators of medium-sized mammals that occur in colonies or
local concentrations, such prairie dogs (Cynomys) and jackrabbits (Lepus).[7][74] Together with the golden eagle, bald eagles are occasionally accused of predating livestock, especially sheep (Ovis aries).
There are a handful of proven cases of lamb predation, some of
specimens weighing up 
to 11 kg (24 lb), by bald eagles but they are much
less likely to attack a healthy lamb than a golden eagle and both
species prefer native, wild prey and are unlikely to cause any extensive
determent to human livelihoods.[75]
There is one case of a bald eagle killing and feeding on an adult,
pregnant ewe (then

joined in eating the kill by at least 3 other
eagles), which, weighing on average over 60 kg (130 lb), is much larger
than any other known prey taken by this species.[76]
Supplemental prey are readily taken given the opportunity. In some areas reptiles may become regular prey, especially warm areas such as Florida where reptile diversity is high. Turtles are perhaps the most regularly hunted type of reptile.[7] In coastal New Jersey, 14 of 20 studied eagle nests included remains of turtles. The main species found were common musk turtles (Sternotherus odoratus), diamondback terrapin

(Malaclemys terrapin) and juvenile common snapping turtles (Chelydra serpentina).
In these New Jersey nests, mainly subadult and small adults were taken,
ranging in carapace length from 9.2 to 17.1 cm (3.6 to 6.7 in).[77] Snakes are also taken occasionally, especially partially aquatic ones, as are amphibians and crustaceans (largely crayfish and crabs).[32][46]
To hunt fish, the eagle swoops down over the water and snatches the fish out of the water with its talons.
They eat by holding the fish in one claw and tearing the flesh with the
other. Eagles have structures on their toes called spicules that allow
them to grasp fish. Osprey also have this adaptation.[40] Bald eagles have powerful talons and have been recorded flying with a 6.8 kg (15 lb) mule deer (Odocoileus

hemionus) fawn.[78] This feat is the record for the heaviest load carrying ever verified for a flying bird.[79]
It has been estimated that the gripping power (pounds by square inch)
of the bald eagle is ten times greater than that of a human.[80]
Bald eagles can fly with fish at least equal to their own weight, but
if the fish is

too heavy to lift, the eagle may be dragged into the
water. It may swim to safety, but some eagles drown or succumb to hypothermia.
Many sources claim that bald eagles, like all large eagles, cannot
normally take flight carrying prey more than half of their own weight
unless aided by favorable wind conditions.[32][56]
On numerous occasions, when large prey such as mature salmon or geese
are attacked, eagles have been seen to make contact and then drag the
prey in a strenuously labored, low flight over the water to a bank,

where they then finish off and dismember the prey.[15]
When food is abundant, an eagle can gorge itself by storing up to 1 kg
(2.2 lb) of food in a pouch in the throat called a crop. Gorging allows
the bird to fast for several days if food becomes unavailable.[32]
Occasionally, bald eagles may hunt cooperatively when confronting prey,
especially relatively large prey such as jackrabbits or herons, with
one bird distracting

potential prey, while the other comes behind it in
order to ambush it.[4][81][82]
While hunting waterfowl, bald eagles repeatedly fly at a target and
cause it to dive repeatedly, hoping to exhaust the victim so it can be
caught (white-tailed eagles have been recorded hunting waterfowl in the
same way). When hunting concentrated prey, a successful catch which
often results in the hunting eagle being pursued by other

eagles and
needing to find an isolated perch for consumption if it is able to carry
it away successfully.[15]
Unlike some other eagle species, bald eagles rarely take on evasive
or dangerous prey on their own. The species mainly target prey which is
much smaller than themselves, with most live fish caught weighing 1 to
3 kg (2.2 to 6.6 lb) and most waterbirds predated weighing 0.2 to 2.7 kg
(0.44 to 5.95 lb).[45][56][83]

They attain much their food as carrion or via a practice known as kleptoparasitism,
where they steal prey away from other predators. Due to their dietary
habits, bald eagles are frequently viewed in a negative light by humans.[7]
Thanks to their superior foraging ability and experience, adults are
generally more likely to hunt live prey than immature eagles, which
often obtain their food from scavenging.[84][85]
They are not very selective about the condition or origin, whether
provided by humans, other animals, auto

accidents or natural causes, of a
carcass's presence, but will avoid eating carrion where disturbances
from humans are a regular occurrence. They will scavenge carcasses up to
the size of whales, though carcasses of ungulates and large fish are seemingly preferred.[15]
Bald eagles also may sometimes feed on subsistence scavenged or stolen
from campsites and picnics, as well as garbage dumps (dump usage is
habitual mainly in Alaska).[86]
When competing for food, eagles will usually dominate other fish-eaters and scavengers, aggressively displacing mammals such as coyotes (Canis latrans) and foxes, and birds such as corvids, gulls, vultures and other raptors.[86] Occasionally, coyotes, bobcats (Lynx rufus) and domestic dogs (Canis lupus

familiaris) can displace eagles from carrion, usually less confident immature birds, as has been recorded in Maine.[87]
Bald eagles are less active, bold predators than golden eagles and get
relatively more of their food as carrion and from kleptoparasitism
(although it is now generally thought that golden eagles eat more
carrion than was previously assumed).[8]
However, the two species are roughly equal in size, aggressiveness and
physical strength and so competitions can go either way. Neither species
is known to be dominant, and the outcome depends on the size and
disposition of the individual eagles involved.[15]
The bald eagle is thought to be much more numerous in North America
than the golden eagle, with the

bald species estimated to number at
least 150,000 individuals, about twice as many golden eagles there are
estimated to live in North America.[8][27] Due to this, bald eagles often outnumber golden eagles at attractive food sources.[8] Despite the potential for contention between these animals, in New Jersey during winter, a golden eagle and numerous bald eagles were observed to hunt snow geese alongside each other without conflict.[88] Similarly, both eagle species have been recorded, via video-monitoring, to feed on gut pills and carcasses of white-tailed deer (Odocoileus virginianus) in remote forest clearings in the eastern Appalachian Mountains without apparent conflict.[8]
Many bald eagles are habitual

kleptoparasites, especially in winters
when fish are harder to come by. They have been recorded stealing fish
from other predators such as ospreys, herons and even otters.[15][89] They have also been recorded opportunistically pirating birds from peregrine falcons (Falco peregrinus), prairie dogs from ferruginous hawks (Buteo regalis) and even jackrabbits from golden eagles.[90][91]
When they approach scavengers like dogs, gulls or vultures at carrion
sites, they often aggressively attack them and try to force them to
disgorge their food.[32] Healthy adult bald eagles are not preyed on in the wild and are thus considered apex predators.[92]

Bald eagles are sexually mature at four or five years of age. When
they are old enough to breed, they often return to the area where they
were born. It is thought that bald eagles
mate for life.
However, if one member of a pair dies or disappears, the other will
choose a new mate. A pair which has repeatedly failed in breeding
attempts may split and look for new mates.
[93]
Bald eagle courtship involves elaborate, spectacular calls and flight
displays. The flight includes swoops, chases, and cartwheels, in which
they fly high, lock talons, and free fall, separating just before
hitting the ground.
[44][94] Usually, a territory defended by a mature pair will be 1 to 2 km (0.62 to 1.24 mi) of waterside habitat.
[7]
Compared to most other raptors which mostly nest in April or May,
bald eagles are early breeders: nest building or reinforcing is often by
mid-February, egg laying is often late February (sometimes during deep
snow in the North), and incubation is usually mid-March and early May.
Eggs hatch from mid April to early May, and the young fledge late June
to early July.[7]
The nest is the largest of any bird in North America; it is used
repeatedly over many years and with new material added each year may
eventually be as large as 4 m (13 ft) deep, 2.5 m (8.2 ft) across and
weigh 1 metric ton (1.1 short tons);[2]
one nest in

Florida was found to be 6.1 m (20 ft) deep, 2.9 meters
(9.5 ft) across, and to weigh 3 short tons (2.7 metric tons).[95] This nest is on record as the largest tree nest ever recorded for any animal.[96]
Usually nests are used for under five years or so, as they either
collapse in storms or break the branches supporting them by

their sheer
weight. However, one nest in the Midwest was occupied continuously for at least 34 years.[32]
The nest is built out of branches, usually in large trees found near
water. When breeding where there are no trees, the bald eagle will nest
on the ground, as has been recorded largely in areas largely isolated
from terrestrial predators, such as Amchitka Island in Alaska.[86] In Sonora, Mexico, eagles have been observed nesting on top of Hecho catcuses (Pachycereus pectinaboriginum).[97] Nests located on cliffs and rock pinnacles have been reported historically in California, Kansas, Nevada, New Mexico and Utah, but currently are only verified to occur only in Alaska and Arizona.[7]
The eggs average about 73 mm (2.9 in)

long, ranging from 58 to 85 mm
(2.3 to 3.3 in), and have a breadth of 54 mm (2.1 in), ranging from 47
to 63 cm (19 to 25 in).[40][44] Eggs in Alaska averaged 130 g (4.6 oz) in mass, while in Saskatchewan they averaged 114.4 g (4.04 oz).[98][99] As with their ultimate body size, egg size tends to increase further away from the Equator.[44]
Eagles produce between one and three eggs per year, two being typical.
Rarely, four eggs have been found in nests but these may be exceptional
cases of polygyny.[100] Eagles in captivity have been capable of producing up to seven eggs.[101]
it is rare for all three chicks to successfully reach the fledging
stage. The oldest chick often bear the advantage of larger size and
louder voice, which tends to draw the parents attention towards them.[7]
Occasionally, as is recorded in many

large raptorial birds, the oldest
sibling sometimes attacks and kills their younger sibling(s), especially
early in the nesting period when their sizes are most different.[7]
However, nearly half of known bald eagle produce two fledgings species
(more rarely three), unlike in some other "eagle" species such as some
in the Aquila genus, in which a second fledging is typically observed in less than 20% of nests

despite two eggs being typically laid.[14]
Both the male and female take turns incubating the eggs, but the female
does most of the incubation. The parent not incubating will hunt for
food or look for nesting material during this stage. For the first two
to three weeks of the nestling period at least one adult is at the nest
almost 100% of the time. After five to six weeks, the attendance of
parents usually drops off considerably (with the parents often perching
in trees nearby).[7] A young eaglet can gain up to 170 g

(6.0 oz) a day, the fastest growth rate of any North American bird.[32]
The young eaglets pick up and manipulate sticks, play tug of war with
each other, practice holding things in their talons, and stretch and
flap their wings. By eight weeks, the eaglets are strong enough to flap
their wings, lift their feet off the nest platform, and rise up in the
air.[32]
The young fledge at anywhere from 8 to 14 weeks of age, though will
remain close to the nest and attended to by their parents for a further 6
weeks. Juvenile eagles first start dispersing away from their parents
about 8 weeks after they fledge. Variability in departure date related
to effects of sex and hatching order on growth and development.[99]
For the next four years, immature eagles wander widely in search of
food until they attain adult plumage and are eligible to reproduce.[102]

The average lifespan of bald eagles in the wild is around 20 years, with the oldest confirmed one having been 28 years of age.[4] In captivity, they often live somewhat longer. In one instance, a captive individual in New York
lived for nearly 50 years. As with size, the average lifespan of an
eagle population appears to

be influenced by its location and access to
prey.[103]
As they are no longer heavily persecuted, adult mortality is quite low.
In one study of Florida eagles, adult bald eagles reportedly had 100%
annual survival rate.[8] In Prince William Sound in Alaska, adults had an annual survival rate of 88% even after the Exxon Valdez oil spill adversely effected eagles in the area.[104]
Of 1,428 individuals from across the range necropsied by National
Wildlife Health Center from 1963 to 1984, 329 (23%) eagles died from
trauma, primarily impact with wires and vehicles; 309 (22%) died from
gunshot; 158 (11%) died from poisoning; 130 (9%) died from
electrocution; 68 (5%) died from trapping; 110 (8%) from emaciation; and

31 (2%) from disease; cause of death was undetermined in 293 (20%) of
cases.[105] In this study, 68% of mortality was human-caused.[105] Today eagle-shooting is believed to be considerably reduced due to the species protected status.[106]
In one case, an adult eagle investigating a peregrine falcon nest for
prey items sustained a concussion from a swooping parent Peregrine, and
ultimately died days later from it.[107] An early natural history video depicts a cougar (Puma concolor)
ambushing and killing an immature bald eagle feeding at a rabbit
carcass is viewable online although this film may have been staged.[108]
Most non-human-related mortality involves nestlings or eggs. Around 50% of eagles survive their first

year.[102] However, in the Chesapeake Bay area, 100% of 39 radio-tagged nestlings survived to their first year.[109]
Occasionally, nestling or egg fatalities are due to nest collapses,
starvation, sibling aggression or inclement weather. Another significant
cause of egg and nestling mortality is predation. These have been
verified to be predated by large gulls, corvids (including ravens, crows and magpies), Wolverines (Gulo gulo), hawks, owls, eagles, bobcats (Lynx rufus), American black bears (Ursus americanus) and raccoons.[98][110][111][112][113][114][115]
If food access is low, parental attendance at the nest may be lower
because

both parents may have to forage thus resulting in less
protection.[14] Nestlings are usually exempt from predation by terrestrial carnivores that are poor tree-climbers, but Arctic foxes (Vulpes lagopus) occasionally snatched nestlings from ground nests on Amchitka Island in Alaska before they were

extirpated from the island.[86]
The bald eagle will defend its nest fiercely from all comers and has
even repelled attacks from bears, having been recorded knocking a black
bear out of a tree when the latter tried to climb a tree holding
nestlings.[116]

Once a common sight in much of the continent, the bald eagle was
severely affected in the mid-20th century by a variety of factors, among
them the thinning of egg shells attributed to use of the pesticide DDT.[117] Bald eagles, like many birds of prey, were especially affected by DDT due to biomagnification. DDT itself was not lethal to the adult bird, but it interfered with the bird's calcium
metabolism, making the
bird either sterile or unable to lay healthy
eggs. Female eagles laid eggs that were too brittle to withstand the
weight of a brooding adult, making it nearly impossible for the eggs to
hatch.[26] It is estimated that in the early 18th century, the bald eagle population was 300,000–500,000,[118] but by the 1950s there were only 412 nesting pairs in the 48 contiguous states
of the US. Other factors in bald eagle population reductions were a
widespread loss of suitable habitat, as well as both legal and illegal
shooting. In 1930 a

New York City ornithologist wrote that in the state
of Alaska in the previous 12 years approximately 70,000 bald eagles had
been shot. Many of the hunters killed the bald eagles under the
long-held beliefs that bald eagles grabbed young lambs and even children
with their talons, yet the birds were innocent of most of these alleged
acts of predation (lamb predation is rare, human predation is thought
to be non-existent).[119]
Later illegal shooting was described as "the leading cause of direct
mortality in both adult and immature bald eagles," according to a 1978
report in the Endangered Species Technical Bulletin. In 1984, the National Wildlife Federation
listed hunting, power-line electrocution, and collisions in flight as
the leading causes of eagle deaths. Bald eagles have also been killed by
oil, lead, and mercury pollution,

and by human and predator intrusion
at nests.[120]
The species was first protected in the U.S. and Canada by the 1918 Migratory Bird Treaty,
later extended to all of North America. The 1940 bald eagle Protection
Act in the U.S., which protected the bald eagle and the golden eagle,
prohibited commercial trapping and killing of the birds. The bald eagle
was declared an endangered species in the U.S. in 1967, and amendments
to the 1940 act between 1962 and 1972 further restricted commercial uses
and increased penalties for violators. Perhaps most significant in the
species' recovery, in 1972, DDT was banned from usage in the United
States.[121] DDT was completely banned in Canada in 1989, though its use had been highly restricted since the late 1970s.[122]
With regulations in place and DDT banned, the eagle population
rebounded. The bald eagle can be found in growing concentrations
throughout the United States and Canada, particularly near large bodies
of water. In the early 1980s, the estimated total population was 100,000
individuals, with 110,000–115,000 by 1992;[2] the U.S. state with the largest resident population is Alaska, with about 40,000–50,000, with

the next highest population the Canadian province of British Columbia with 20,000–30,000 in 1992.[2]
Obtaining a precise count of bald eagles population is extremely
difficult. The most recent data submitted by individual states was in
2006, when 9789 breeding pairs were reported.[123] For some time, the stronghold breeding population of bald eagles in the lower 48 states was in Florida, where over a thousand pairs have held on while populations in other states were significantly reduced by DDT use. Today, the contiguous state with the largest number of breeding pairs of eagles is Minnesota
with an estimated 1,312 pairs, surpassing Florida's most recent count
of 1,166 pairs. 23, or nearly half, of the 48 contiguous states now have
at least 100 breeding pairs of bald eagles.[27]

The bald eagle was officially removed from the U.S. federal
government's list of endangered species on July 12, 1995, by the U.S.
Fish & Wildlife Service, when it was reclassified from "Endangered"
to "Threatened." On July 6, 1999, a proposal was initiated "To Remove
the Bald Eagle in the Lower 48 States From the List of Endangered and
Threatened Wildlife." It was de-listed on June 28, 2007.[124] It has also been assigned a risk level of Least Concern category on the IUCN Red List.[1] In the Exxon Valdez Oil Spill of 1989 an estimated 247 were killed in Prince William Sound, though the local population returned to its pre-spill level by 1995.[4]

Permits
are required to keep bald eagles in captivity in the United States.
Permits are primarily issued to public educational institutions, and the
eagles which they show are permanently injured individuals which cannot
be released to the wild. The facilities where eagles are kept must be
equipped with adequate caging and facilities, as well as workers
experienced in the handling and care of eagles. Bald eagles cannot

legally be kept for falconry
in the United States. As a rule, the bald eagle is a poor choice for
public shows, being timid, prone to becoming highly stressed, and
unpredictable in nature. Native American tribes can obtain a "Native
American Religious Use" permit to keep non-releasable eagles as well.
They use their naturally molted feathers for religious and cultural
ceremonies. The bald eagle can be long-lived in captivity if well cared
for, but does not breed well even under the best conditions.[125] In Canada, a license is required to keep bald eagles for falconry.[126]
The bald eagle is a sacred bird in some North American cultures, and its feathers, like those of the golden eagle, are central to many religious and spiritual customs among Native Americans. Eagles are considered spiritual messengers between gods and humans by some cultures.[127] Many pow wow
dancers use the eagle claw as
part of their regalia as well. Eagle
feathers are often used in traditional ceremonies, particularly in the
construction of regalia worn and as a part of fans, bustles and head
dresses. The Lakota,
for instance, give an eagle feather as a symbol of honor to person who
achieves a task. In modern times, it may be given on an event

such as a
graduation from college.[128] The Pawnee
considered eagles as symbols of fertility because their nests are built
high off the ground and because they fiercely protect their young. The

Kwakwaka'wakw scattered eagle down to welcome important guests.[129] The Choctaw explained that the bald eagle, who has direct contact with the upper world of the sun, is a symbol of peace.[130]
During the Sun Dance, which is practiced by many Plains Indian
tribes, the eagle is represented in several ways. The eagle nest is
represented by the fork of the lodge where the dance is held. A whistle
made from the wing bone of an eagle is used during the course of the
dance. Also during the dance, a medicine man
may direct his fan, which is made of eagle feathers, to people who seek
to be healed. The medicine man touches the fan to the center pole and
then to the patient, in order to transmit power from the pole to the
patient. The fan is then held up toward the sky, so that the eagle may
carry the prayers for the sick to the
Creator.[131]
Current eagle feather law
stipulates that only individuals of certifiable Native American
ancestry enrolled in a federally recognized tribe are legally authorized
to obtain or possess bald or golden eagle feathers for religious or
spiritual use. The constitutionality of these laws has been questioned
by Native American groups on the basis that it violates the First Amendment by affecting ability to practice their religion freely.[132][133]

The National Eagle Repository, a division of the FWS, exists as a means to receive, process, and store bald and golden eagles which are found dead, and to distribute the eagles, their parts and feathers, to federally recognized Native American tribes for use in religious ceremonies.[134]
The bald eagle is the national bird of the United States of America.[135] The founders of the United States were fond of comparing their new republic with the Roman Republic, in which eagle imagery (usually involving the golden eagle) was prominent. On June 20, 1782, the Continental Congress adopted the still-current design for the Great Seal of the United States including a bald eagle grasping 13 arrows and a 13-

leaf olive branch with its talons.[136][137][138]
The bald eagle appears on most official seals of the U.S. government, including the presidential seal, the presidential flag, and in the logos
of many U.S. federal agencies. Between 1916 and 1945, the presidential
flag (but not the seal) showed an eagle facing to its left (the viewer's
right), which gave rise to the urban legend that the flag is changed to have the eagle face towards the olive branch in peace, and towards the

Contrary to popular legend, there is no evidence that Benjamin Franklin ever publicly supported the wild turkey (Meleagris gallopavo),
rather than the bald eagle, as a symbol of the United States. However,
in a letter written to his daughter in 1784 from Paris, criticizing the Society of the Cincinnati, he stated his personal distaste for the bald eagle's behavior. In the letter Franklin states:[4]
Franklin opposed the creation of the Society because he viewed it, with its hereditary membership, as a noble order unwelcome in the newly independent Republic, contrary to the ideals of Lucius Quinctius Cincinnatus,
for whom the Society was named; his reference to the two kinds of birds
is interpreted as a satirical comparison between the Society of the
Cincinnati and


