Difference between revisions of "Field Guide/Birds/Haliaeetus leucocephalus"

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{{otheruses}}
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{{Taxobox
 
{{Taxobox
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| color = pink
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| color = neon red
 
| name = Bald Eagle
 
| name = Bald Eagle
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| status = {{StatusLeastConcern}}
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| status = LC
 
| image = Haliaeetus leucocephalus.jpg
 
| image = Haliaeetus leucocephalus.jpg
 
| regnum = [[Animal]]ia
 
| regnum = [[Animal]]ia
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| phylum = [[Chordate|Chordata]]
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| phylum = [[Chordata]]
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| classis = [[Bird|Aves]]
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| classis = [[Aves]]
 
| ordo = [[Falconiformes]]
 
| ordo = [[Falconiformes]]
 
| familia = [[Accipitridae]]
 
| familia = [[Accipitridae]]
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| binomial = ''Haliaeetus leucocephalus''
 
| binomial = ''Haliaeetus leucocephalus''
 
| binomial_authority = ([[Carolus Linnaeus|Linnaeus]], [[1766]])
 
| binomial_authority = ([[Carolus Linnaeus|Linnaeus]], [[1766]])
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| subdivision_ranks = [[Subspecies]]
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| subdivision =
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* ''H. l. leucocephalus'' {{Taxobox_authority | author = (Linnaeus | date = 1766)}}<br/><small>Southern Bald Eagle</small>
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* ''H. l. washingtoniensis'' {{Taxobox_authority | author = [[John James Audubon|Audubon]] | date = [[1827]])}}<br/><small>Northern Bald Eagle or Washington's Eagle</small>
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| synonyms =
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''Falco leucocephalus'' {{Taxobox_authority | author = Linnaeus | date = 1766}}<br/>
 
}}
 
}}
  
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The '''Bald Eagle''' (''Haliaeetus leucocephalus'') is a [[bird of prey]] originating in [[North America]], most recognizable as the [[national bird]] of the [[United States]]. The species was on the brink of [[extinction]] late in the [[20th century]] but now has a stable population and is in the process of being removed from the [[Federal government of the United States|U.S. federal government]]'s list of [[endangered species]].  
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The '''Bald Eagle''' ('''''Haliaeetus leucocephalus'''''), also known as the '''American Eagle''', is a [[bird of prey]] found in [[North America]], most recognizable as the [[national bird]] of the [[United States]].  
 +
 
 +
The species was on the brink of [[extinction]] in the US late in the 20th century, but now has a stable population and is in the process of being removed from the [[Federal government of the United States|U.S. federal government]]'s list of [[endangered species]]. 
 +
 
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This [[eagle]] gets both its common and scientific names from the distinctive appearance of the adult's head. ''Bald'' in the [[English language|English]] name refers to the white head feathers, and 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 ''leukos'' ("white") and ''kephale'' ("head").
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==Description and systematics==
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[[Image:Imm_Bald.jpg|thumb|200px|left|Underside of an immature [[Bald Eagle]] photographed while thermalling with a [[glider]] over the [[Bald Eagle Valley]] of [[Pennsylvania]] USA during the fall migration.]]
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An immature Bald Eagle has speckled brown [[plumage]], the distinctive white head and body developing 2-3 years later, before sexual maturity. This species is distinguishable from the [[Golden Eagle]] in that the latter has feathers which extend down the legs. Also, the immature Bald Eagle has more light feathers in the upper arm area, especially around the 'armpit'.
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Adult females have an average wingspan of about 7 feet (2.1 meters); adult males have a wingspan of 6 ft 6 in (2 meters). Adult females weigh approximately 12.8 lb (5.8 kg), males weigh 9 lb (4.1 kg). The smallest specimens are those from Florida, where an adult male may barely exceed 5 lb (2.3 kg) and a wingspan of 6 feet (1.8 meters). The largest are the Alaskan birds, where large females may exceed 15.5 lb (7 kg) and have a wingspan of approximately 8 feet (2.4 meters).
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The northern birds are the [[subspecies]] ''washingtoniensis'', whereas the southern ones belong to the [[nominate subspecies]] ''leucocephalus''. They are separated approximately at [[latitude]] 38° N, or roughly the latitude of [[San Francisco]]; northern birds reach a bit further south on the [[Atlantic Coast]], where they occur south to the [[Cape Hatteras]] area. Audubon's [[type specimen]] of '''"Washington's Eagle"''' - named in honor of [[George Washington]]<ref>
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As explicitly stated by Audubon. However, the [[subspecific name]] he chose - ''washingtoniensis'' - means properly "from Washington (state)". There has been considerable confusion, with some authors changing it to ''washingtoni'', "(George) Washington's", but the form as originally written is correct.</ref>
 +
- was apparently an exceptionally large bird, such as are more often found in [[Alaska]]; these have been proposed as subspecies ''alascanus'' or ''alascensis'', but the variation is [[Cline (population genetics)|clinal]] and follows [[Bergmann's Rule]].
  
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The bird gets both its common and scientific names from the distinctive appearance of the adult's head. ''Bald'' in the [[English language|English]] name refers to the white head feathers, and the scientific name is derived from ''Haliaeetus'', the [[New Latin]] for "sea eagle," (from the [[Greek language|Greek]] ''haliaetos'') and ''leucocephalus'', the Greek for "white head," from ''leukos'' ("white") and ''kephale'' ("head").
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The Bald Eagle forms a [[species pair]] with the [[Eurasia]]n [[White-tailed Eagle]]. These diverged from other Sea Eagles at the beginning of the Early [[Miocene]] (c. 10 [[mya (unit)|mya]]) at latest, possibly - if the most ancient fossil record is correctly assigned to this [[genus]] - as early as the Early/Middle [[Oligocene]], some 28 mya (Wink ''et al.'' 1996<ref>
 +
The authors' reservations about using the generalized "2%" rate of [[molecular evolution]] have since proven to be well-founded.</ref>).
 +
As in other sea-eagle species pairs, this one consists of a white-headed (the Bald Eagle) and a tan-headed species. They probably diverged in the North [[Pacific]], spreading westwards into Eurasia and eastwards into [[North America]]. Like the third northern species, [[Steller's Sea-eagle]], they have yellow talons, beaks and eyes in adults.  
  
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==Range and habitat==
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Bald Eagles are powerful fliers, and also soar on thermal convection currents.
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Bald Eagles can be found in small concentrations throughout the U.S. and [[Canada]], particularly near large [[body of water|bodies of water]]. The state with the largest resident population is [[Alaska]]; out of the estimated 100,000 Bald Eagles on [[Earth]], half live in Alaska.
 
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==Description==
 
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[[Image:bald.eagle.longshot.arp.500pix.jpg|200px|thumb|left|Bald Eagle at Combe Martin Wildlife and Dinosaur Park, North Devon, England]]
 
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An immature bird has speckled brown [[feather]]s all over, the distinctive head and body [[plumage]] arriving 2&ndash;3 years later, before sexual maturity. Adult females have a wingspan of approximately 2.1 meters (7 feet); adult males have a wingspan of 2 meters (6 feet, 6 inches). Adult females weigh approximately 5.8&nbsp;kg (12.8&nbsp;lb), males weigh 4.1&nbsp;kg (9&nbsp;lb).
 
  
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Bald Eagles are protected by two federal laws in the [[United States]]: the Eagle Law which protects Bald and [[Golden Eagle]]s and the Migratory Bird Act. They were on the Endangered Species list until their removal on February 13, 2006. Fuck the Bald Eagle he can suck my balls!
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In the wild, Bald Eagles can live about 20-30 years, and have a maximum life span of approximately 50 years. They generally live longer in captivity; up to 60 years old.  
  
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==Behavior==
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Bald Eagles normally squeak and have a shrill cry, punctuated by grunts. They do not make the "eagle scream" as often shown on the television. What many recognize as the call of this species is actually the call of a [[Red-tailed Hawk]] dubbed into the film.
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Bald Eagles build huge nest platforms out of branches, usually in large trees. Pairs, who mate for life, add material to the nest each breeding season. After several years, the nest may weigh upwards of a thousand pounds or more.
 
  
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Bald Eagles which are old enough to nest often return to the area in which they were raised. They are more social than many other raptor species: an adult bald eagle looking for a nesting site is more likely to select a location that contains other immature eagles than one with no eagle population.
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==Range, habitat, and restoration==
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[[Image:bald.eagle.longshot.arp.500pix.jpg|200px|thumb|left|Adult at Combe Martin Wildlife and Dinosaur Park, North Devon, England]]
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The Bald Eagle's natural range covers most of North America, including most of [[Canada]], all of the continental United States, and northern [[Mexico]]. The bird itself is able to live in most of North America's varied habitats from the [[bayou]]s of [[Louisiana]] to the [[Sonoran Desert|Sonoran desert]] and the eastern deciduous forests of [[Quebec]] and [[New England]]. It can be a [[bird migration|migratory]] bird but it also is not unheard of for a nesting pair to overwinter in its breeding area.
  
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Bald Eagles are powerful fliers, and ride thermal convection currents to range far.
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Once a common sight in much of the continent, the Bald Eagle was severely affected by the use of the pesticide [[DDT]] in the mid-twentieth century. While the pesticide itself was not lethal to the bird, it made an eagle either sterile or unable to lay healthy eggs: the eagle would ingest the chemical through its food and then lay eggs that were too brittle to withstand the weight of a brooding adult. By the 1960s there were fewer than 500 nesting pairs in the 48 [[Contiguous United States|contiguous states]] of the USA.
  
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They have a long lifespan, with reports of birds in captivity living to be 60 years old.
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Currently it is still slowly but steadily recovering its numbers; Organizations like the [[Fraternal Order of Eagles]] which carry the Eagle as their emblem, have helped the American Bald Eagle on its recovery, by supporting other groups that rescue and preserve the Eagles and their habitat. The Bald Eagle can be found in growing concentrations throughout the United States and [[Canada]], particularly near large [[body of water|bodies of water]]. The [[U.S. state]] with the largest resident population is [[Alaska]]; out of the estimated 70,000 Bald Eagles on [[Earth]], half live there.  
  
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They do not scream as often shown on television. Usually the call of a red-tailed hawk is placed over the image of a flying eagle. They squeak and have a shrill cry, punctuated by grunts.
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Permits are required to keep this species in captivity (e-CFR 1974). As a rule, the Bald Eagle is a poor choice for public shows, being timid, prone to becoming highly stressed, and unpredictable in nature. As remarked above, they can be long-lived in captivity in key demands are met, but do not breed well even under the best conditions. The only Bald Eagle to be born outside North America hatched on [[May 3]], [[2006]] in [[Magdeburg]] Zoo, [[Germany]].
  
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==Reproduction==
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This species has occurred as a [[Vagrancy (biology)|vagrant]] once in [[Ireland]]. The exhausted specimen was discovered by a [[national park]]s worker in a northern [[heath]]. Presumably, a storm blew it out to sea, and the bird struggled across the [[Atlantic Ocean]].
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Bald Eagles are sexually mature at 4 or 5 years of age. Mated pairs produce between one and three [[egg (biology)|egg]]s per year, but it is rare for all three chicks to successfully fledge. Third chicks are sometimes removed from nests to use in [[reintroduction]] programs in areas where the species has died out.  
 
  
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In such programs, the [[bird]]s are raised in boxes, on platforms in the tree canopy, and fed in such a way that they cannot see the person supplying their food, until they are old enough to fly and find their own food.
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==Reproduction==
 +
[[Image:Haliaeetus leucocephalus1.jpg|thumb|right|Two bald eagle chicks]]
 +
Bald Eagles build huge nests out of branches, usually in large trees near water. The nest may stretch as large as eight feet across and weigh up to a ton (907kg). When breeding where there are no trees, the Bald Eagle will nest on the ground.
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 +
Eagles that are old enough to breed often return to the area where they were born. An adult looking for a  site is likely to select a spot that contains other breeding Bald Eagles.
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 +
Bald Eagles are sexually mature at 4 or 5 years old. Eagles produce between one and three eggs per year, but it is rare for all three chicks to successfully fly. Both the male and female take turns sitting on the eggs. The other parent will hunt for food or look for nest material.
  
 
==Diet==
 
==Diet==
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The Bald Eagle's diet is varied, including [[carrion]], [[fish]], smaller [[bird]]s, [[rodent]]s, and sometimes food scavenged or stolen from campsites and picnics.
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The Bald Eagle's diet is varied, including [[carrion]], [[fish]], smaller [[bird]]s, [[rodent]]s, and sometimes food scavenged or stolen from campsites and picnics. Most prey is quite a bit smaller than the eagle, but rare predatory attacks on large birds such as the [[Snow Goose]], the [[Great Blue Heron]] or even [[swan]]s have been recorded. Also, fairly large [[salmon]] and [[trout]] have been taken as well.
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To hunt, 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 spiricules that allow them to grasp fish. [[Osprey]] also have this adaptation.
+
 
 +
To hunt fish, easily their most important live prey, 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 [[spiricules]] that allow them to grasp fish. [[Osprey]] also have this adaptation. Bald Eagles have powerful talons. In one case, an eagle was able to fly off with the 6.8 kg (15 lb) carcass of a [[Mule Deer]] fawn.
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 +
Sometimes, if the fish is too heavy to lift, the eagle will be dragged into the water. It may swim to safety, but some eagles drown or succumb to [[hypothermia]]. Occasionally, Bald Eagles will pirate fish away from [[Osprey]]s and usually the smaller raptors will have to give up their prey, a practice known as [[kleptoparasitism]].
  
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Sometimes, if the [[fish]] is too heavy, the eagle will be dragged into the water. It may swim to safety, but some eagles drown or succumb to [[hypothermia]].
+
==National bird of the U.S.==
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[[Image:Bald eagle.jpg|thumb|right|250px|Bald Eagle portrait]]
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The Bald Eagle is the national bird of the [[United States]] of America. It is probably one of the country's most recognizable symbols, and appears on most of its official seals, including the [[Seal of the President of the United States]].
  
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==Eagles and humans==
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Its national significance dates back to [[June 20]], [[1782]], when  the [[Continental Congress]] officially adopted the current design for the [[Great Seal of the United States]] including a Bald Eagle grasping arrows and an olive branch with its [[talons]].  Some states had earlier did so in 1778.
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As the symbol of the United States the bald eagle is sought after in captivity.  As a rule they are poor birds for public shows being timid and prone to becoming highly stressed.
 
  
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Due to their immense strength and unpredictable nature bald eagles should only be kept by very competently trained individuals who have all the proper permits.
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In 1784, after the end of the [[Revolutionary War]], [[Benjamin Franklin]] wrote a famous letter to his daughter from [[Paris]] criticizing the choice and suggesting the [[Wild Turkey]]'s character as a desirable trait:
  
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==Rare vagrant==
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<blockquote>''For my own part I wish the Bald Eagle had not been chosen the Representative of our Country. He is a Bird of bad moral  character.   He does not get his Living honestly. You may have seen him perched on some dead Tree near the River, where, too lazy to fish for himself, he watches the Labour of the Fishing Hawk; and when that diligent Bird has at length taken a Fish, and is bearing it to his Nest for the Support of his Mate and young Ones, the Bald Eagle pursues him and takes it from him.</blockquote>
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This species has occurred as a [[Vagrancy (biology)|vagrant]] once in [[Ireland]]. The exhausted specimen was discovered by a [[national park]]s worker in a northern heath. Presumably, a storm blew it out to sea, and the bird struggled across the [[Atlantic Ocean]].
 
  
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==National Bird of the US==
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<blockquote>''With all this Injustice, he is never in good Case but like those among Men who live by Sharping & Robbing he is generally poor and often very lousy. Besides he is a rank Coward: The little [[kingbird|King Bird]] not bigger than a Sparrow attacks him boldly and drives him  out of the District. He is therefore by no means a proper Emblem for the brave and honest country of America who have driven all the King birds from our Country...</blockquote>
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The Bald Eagle is the national bird of the United States of America. Its national significance dates back to June 20, [[1782]], when  the [[Continental Congress]] officially adopted the current design for the [[Great Seal of the United States]] including a bald eagle grasping arrows and an olive branch with its [[talons]]. Some states had earlier adopted the bird as a symbol; for example [[New York State]] did so in [[1778]].
 
  
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In [[1784]], after the end of the [[Revolutionary War]], [[Benjamin Franklin]] wrote a famous letter to his daughter from [[Paris]] criticizing the choice and suggesting the [[Wild Turkey]] as an alternative:
+
<blockquote>''I am on this account not displeased that the Figure is not known as a Bald Eagle, but looks more like a Turkey. For the Truth the  Turkey is in Comparison a much more respectable Bird, and withal a true original Native of America . . . He is besides, though a  little vain & silly, a Bird of Courage, and would not hesitate to attack a Grenadier of the British Guards who should presume to invade his Farm Yard with a red Coat on.''</blockquote>
  
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:''For my own part I wish the Bald Eagle had not been chosen the Representative of our Country. He is a Bird of bad moral  character.   He does not get his Living honestly. You may have seen him perched on some dead Tree near the River, where, too lazy to fish for himself, he watches the Labour of the Fishing Hawk; and when that diligent Bird has at length taken a Fish, and is bearing it to his Nest for the Support of his Mate and young Ones, the Bald Eagle pursues him and takes it from him.
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Despite Franklin's objections, the Bald Eagle remained the emblem of the United States. It can be found on both national seals and on the back of several coins (including the [[Quarter (U.S. coin)|quarter]] dollar coin until 1999), with its head oriented towards the olive branch. Between [[1916]] and [[1945]], the [[Presidential Flag]] showed an eagle facing to its left (the viewer's right), which gave rise to the [[urban legend]] that the seal is changed to have the eagle face towards the olive branch in peace, and towards the arrows in wartime.<ref>{{cite web |url=http://www.snopes.com/history/american/turnhead.htm |title=http://www.snopes.com/history/american/turnhead.htm |accessdate= |format= |work= }}</ref>
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:''With all this Injustice, he is never in good Case but like those among Men who live by Sharping & Robbing he is generally poor and often very lousy. Besides he is a rank Coward: The little King Bird not bigger than a Sparrow attacks him boldly and drives him  out of the District. He is therefore by no means a proper Emblem for the brave and honest Cincinnati of America who have driven all the King birds from our Country . . .
 
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:''I am on this account not displeased that the Figure is not known as a Bald Eagle, but looks more like a Turkey. For the Truth the Turkey is in Comparison a much more respectable Bird, and withal a true original Native of America . . . He is besides, though a  little vain & silly, a Bird of Courage, and would not hesitate to attack a Grenadier of the British Guards who should presume to invade his Farm Yard with a red Coat on.''
 
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Despite Franklin's objections the Bald Eagle remained the emblem of the United States. Today it appears on many official seals in addition to the back of 25 cent coin.
 
  
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==Gallery==
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[[Image:BaldeagleYSNP.JPG|thumb|right|250px|Bald Eagle at Yellowstone National Park]]
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<gallery>
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Image:Bald eagle.jpg|Adult
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== Bald Eagles as religious objects ==
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Image:Bald-eagle.jpg|Adult resting
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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 amongst [[Indigenous peoples of the Americas|Native Americans]]. Some Native Americans revere eagles as sacred religious objects, including the feathers and other parts and are often compared to the [[Bible]] and [[crucifix]] (AP 2004).
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Image:Haliaeetus_leucocephalus.jpeg|Adult
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Image:Bald Eaglehead.jpg
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Eagle feathers are often used in traditional ceremonies and are used to honor noteworthy achievements and qualities such as exceptional leadership and bravery.
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Image:A03 4663 1024x683.JPG|Female on nest with egg
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</gallery>
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Despite modern and historic Native American practices of giving eagle feathers to non-Native Americans and Native American members of other tribes who have been deemed worthy, current [[eagle feather law]] stipulates that only individuals of certifiable Native American ancestry enrolled in a federally recognized tribe are legally authorized to obtain Bald or Golden Eagle feathers for [[religious]] or [[spiritual]] use (AP 2002) Attempts to extend this permitted use have met with resistance from members of federally recognized Native American tribes, who even under the permissive legislation sometimes have to wait for years before a good specimen can be procured for their use (AP 2004).
 +
 
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 +
==References==
 +
* '''Associated Press''' (AP) (2002): ''[http://www.freedomforum.org/templates/document.asp?documentID=16684 Native American gets OK to use eagle feathers in religious practices]''. Retrieved 2006-NOV-30.
 +
 
 +
* '''Associated Press''' (AP) (2004): ''[http://www.wwrn.org/article.php?idd=4949&sec=73&cont=6 Residents fight to use eagle feathers]''. Retrieved 2006-NOV-30.
 +
 
 +
* {{IUCN2006|assessors='''BirdLife International'''|year=2004|id=49336|title=Haliaeetus leucocephalus|downloaded=09 May 2006}} Database entry includes justification for why this species is of least concern
 +
 
 +
* '''Boradiansky''', Tina S. (1990): ''[http://www.animallaw.info/articles/arus30nrj709.htm Conflicting Values: The Religious Killing of Federally Protected Wildlife]''. Retrieved 2006-NOV-30.
 +
 
 +
* '''DeMeo''', Antonia M. (1995): Access to Eagles and Eagle Parts: Environmental Protection v. Native American Free Exercise of Religion. ''Hastings Constitutional Law Quarterly'' '''22'''(3): 771-813. [http://www.animallaw.info/articles/ar22hstclq771.htm HTML fulltext]
 +
 
 +
* '''Electronic Code of Federal Regulations''' (e-CFR) (1974): ''Title 50: Wildlife and Fisheries. Part 22 - Eagle Permits''. [http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid=8f792182cc6e2d5c11136fe0db280d2b&rgn=div5&view=text&node=50:6.0.1.1.5&idno=50 HTML fulltext]
 +
 
 +
* '''Wink''', M.; Heidrich, P. & Fentzloff, C. (1996): A mtDNA phylogeny of sea eagles (genus ''Haliaeetus'') based on nucleotide sequences of the cytochrome ''b'' gene. ''Biochemical Systematics and Ecology'' '''24''': 783-791. {{DOI|10.1016/S0305-1978(96)00049-X}} [http://www.uni-heidelberg.de/institute/fak14/ipmb/phazb/pubwink/1996/20_1996.pdf PDF fulltext]
 +
 
 +
===Footnotes===
 +
<references/>
  
 
==External links==
 
==External links==
 
{{commons|Haliaeetus leucocephalus}}
 
{{commons|Haliaeetus leucocephalus}}
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*[http://images.fws.gov/default.cfm?fuseaction=records.display&CFID=2060719&CFTOKEN=64720564&id=5C7D1A7F%2DF41E%2D4C0A%2D87A4F0A6E628BD0E 11.9" x 8" 1.24 MB Bald Eagle JPEG] provided by the U.S. Fish & Wildlife Service
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*[http://www.baldeagleinfo.com/ Bald Eagle Info.com]. Retrieved 2006-NOV-30.
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*[http://www.greatseal.com/symbols/turkey.html Ben Franklin - the Eagle and the Turkey]
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*BirdHouses101.com: [http://www.birdhouses101.com/bald-eagle.asp Bald Eagle]. Retrieved 2006-NOV-30.
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*[http://www.nwf.org/wildlife/baldeagle/nationalbird.cfm?photo=1 Eagle vs. Turkey]
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*[http://www.eraptors.org/index.html Cascades Raptor Center]. Retrieved 2006-NOV-30.
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*GreatSeal.com: [http://www.greatseal.com/symbols/turkey.html The Eagle, Ben Franklin, and the Turkey]. Retrieved 2006-NOV-30.
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<!--Categories-->
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*NE Energy: [http://www.nu.com/eagles/default.asp Barton Island, Massachusetts, Bald Eagle webcam]. Retrieved 2006-NOV-30.
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*[[USFWS]]: [http://images.fws.gov/default.cfm?fuseaction=records.display&CFID=2060719&CFTOKEN=64720564&id=5C7D1A7F%2DF41E%2D4C0A%2D87A4F0A6E628BD0E  1.24 MB Bald Eagle JPEG]. Retrieved 2006-NOV-30.
  
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<!--Interlanguage links-->
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<!-- *[http://www.infotecbusinesssystems.com/wildlife/default.asp Live web cam of a Bald Eagle nest in British Columbia] dead as of 2006-NOV-30 -->
  
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[[Category:Avifauna of Canada]]
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[[Category:Avifauna of Southeastern United States]]
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[[Category:Avifauna of the United States]]
 
[[Category:Eagles]]
 
[[Category:Eagles]]
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[[Category:Haliaeetus]]
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[[Category:Fauna of Minnesota|Eagle, bald]]
  
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[[be:Белагаловы арол]]
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[[cs:Orel bělohlavý]]
 
[[da:Hvidhovedet havørn]]
 
[[da:Hvidhovedet havørn]]
 
[[de:Weißkopfseeadler]]
 
[[de:Weißkopfseeadler]]
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[[es:Pigargo cabeciblanco]]
 
[[eo:Blankkapa maraglo]]
 
[[eo:Blankkapa maraglo]]
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[[fi:Valkopäämerikotka]]
 
 
[[fr:Pygargue à tête blanche]]
 
[[fr:Pygargue à tête blanche]]
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[[it:Haliaeetus leucocephalus]]
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[[he:עיטם לבן ראש]]
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[[nl:Amerikaanse zeearend]]
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[[cr:ᒥᒋᓲ]]
 
[[ja:ハクトウワシ]]
 
[[ja:ハクトウワシ]]
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[[nl:Amerikaanse zeearend]]
 
 
[[pl:Bielik amerykański]]
 
[[pl:Bielik amerykański]]
 
[[pt:Águia de cabeça branca]]
 
[[pt:Águia de cabeça branca]]
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[[sk:Orliak bielohlavý]]
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[[fi:Valkopäämerikotka]]
 
[[sv:Vithövdad havsörn]]
 
[[sv:Vithövdad havsörn]]
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[[ta:வெண்தலைக் கழுகு]]

Latest revision as of 18:51, 5 July 2012

Template:Otheruses

Template:Taxobox

The Bald Eagle (Haliaeetus leucocephalus), also known as the American Eagle, is a bird of prey found in North America, most recognizable as the national bird of the United States.

The species was on the brink of extinction in the US late in the 20th century, but now has a stable population and is in the process of being removed from the U.S. federal government's list of endangered species.

This eagle gets both its common and scientific names from the distinctive appearance of the adult's head. Bald in the English name refers to the white head feathers, and 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 leukos ("white") and kephale ("head").

Description and systematics

File:Imm Bald.jpg
Underside of an immature Bald Eagle photographed while thermalling with a glider over the Bald Eagle Valley of Pennsylvania USA during the fall migration.

An immature Bald Eagle has speckled brown plumage, the distinctive white head and body developing 2-3 years later, before sexual maturity. This species is distinguishable from the Golden Eagle in that the latter has feathers which extend down the legs. Also, the immature Bald Eagle has more light feathers in the upper arm area, especially around the 'armpit'.

Adult females have an average wingspan of about 7 feet (2.1 meters); adult males have a wingspan of 6 ft 6 in (2 meters). Adult females weigh approximately 12.8 lb (5.8 kg), males weigh 9 lb (4.1 kg). The smallest specimens are those from Florida, where an adult male may barely exceed 5 lb (2.3 kg) and a wingspan of 6 feet (1.8 meters). The largest are the Alaskan birds, where large females may exceed 15.5 lb (7 kg) and have a wingspan of approximately 8 feet (2.4 meters).

The northern birds are the subspecies washingtoniensis, whereas the southern ones belong to the nominate subspecies leucocephalus. They are separated approximately at latitude 38° N, or roughly the latitude of San Francisco; northern birds reach a bit further south on the Atlantic Coast, where they occur south to the Cape Hatteras area. Audubon's type specimen of "Washington's Eagle" - named in honor of George Washington& - was apparently an exceptionally large bird, such as are more often found in Alaska; these have been proposed as subspecies alascanus or alascensis, but the variation is clinal and follows Bergmann's Rule.

The Bald Eagle forms a species pair with the Eurasian White-tailed Eagle. These diverged from other Sea Eagles at the beginning of the Early Miocene (c. 10 mya) at latest, possibly - if the most ancient fossil record is correctly assigned to this genus - as early as the Early/Middle Oligocene, some 28 mya (Wink et al. 1996&). As in other sea-eagle species pairs, this one consists of a white-headed (the Bald Eagle) and a tan-headed species. They probably diverged in the North Pacific, spreading westwards into Eurasia and eastwards into North America. Like the third northern species, Steller's Sea-eagle, they have yellow talons, beaks and eyes in adults.

Bald Eagles are powerful fliers, and also soar on thermal convection currents.

In the wild, Bald Eagles can live about 20-30 years, and have a maximum life span of approximately 50 years. They generally live longer in captivity; up to 60 years old.

Bald Eagles normally squeak and have a shrill cry, punctuated by grunts. They do not make the "eagle scream" as often shown on the television. What many recognize as the call of this species is actually the call of a Red-tailed Hawk dubbed into the film.

Range, habitat, and restoration

Adult at Combe Martin Wildlife and Dinosaur Park, North Devon, England

The Bald Eagle's natural range covers most of North America, including most of Canada, all of the continental United States, and northern Mexico. The bird itself is able to live in most of North America's varied habitats from the bayous of Louisiana to the Sonoran desert and the eastern deciduous forests of Quebec and New England. It can be a migratory bird but it also is not unheard of for a nesting pair to overwinter in its breeding area.

Once a common sight in much of the continent, the Bald Eagle was severely affected by the use of the pesticide DDT in the mid-twentieth century. While the pesticide itself was not lethal to the bird, it made an eagle either sterile or unable to lay healthy eggs: the eagle would ingest the chemical through its food and then lay eggs that were too brittle to withstand the weight of a brooding adult. By the 1960s there were fewer than 500 nesting pairs in the 48 contiguous states of the USA.

Currently it is still slowly but steadily recovering its numbers; Organizations like the Fraternal Order of Eagles which carry the Eagle as their emblem, have helped the American Bald Eagle on its recovery, by supporting other groups that rescue and preserve the Eagles and their habitat. The Bald Eagle can be found in growing concentrations throughout the United States and Canada, particularly near large bodies of water. The U.S. state with the largest resident population is Alaska; out of the estimated 70,000 Bald Eagles on Earth, half live there.

Permits are required to keep this species in captivity (e-CFR 1974). As a rule, the Bald Eagle is a poor choice for public shows, being timid, prone to becoming highly stressed, and unpredictable in nature. As remarked above, they can be long-lived in captivity in key demands are met, but do not breed well even under the best conditions. The only Bald Eagle to be born outside North America hatched on May 3, 2006 in Magdeburg Zoo, Germany.

This species has occurred as a vagrant once in Ireland. The exhausted specimen was discovered by a national parks worker in a northern heath. Presumably, a storm blew it out to sea, and the bird struggled across the Atlantic Ocean.

Reproduction

Two bald eagle chicks

Bald Eagles build huge nests out of branches, usually in large trees near water. The nest may stretch as large as eight feet across and weigh up to a ton (907kg). When breeding where there are no trees, the Bald Eagle will nest on the ground.

Eagles that are old enough to breed often return to the area where they were born. An adult looking for a site is likely to select a spot that contains other breeding Bald Eagles.

Bald Eagles are sexually mature at 4 or 5 years old. Eagles produce between one and three eggs per year, but it is rare for all three chicks to successfully fly. Both the male and female take turns sitting on the eggs. The other parent will hunt for food or look for nest material.

Diet

The Bald Eagle's diet is varied, including carrion, fish, smaller birds, rodents, and sometimes food scavenged or stolen from campsites and picnics. Most prey is quite a bit smaller than the eagle, but rare predatory attacks on large birds such as the Snow Goose, the Great Blue Heron or even swans have been recorded. Also, fairly large salmon and trout have been taken as well.

To hunt fish, easily their most important live prey, 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 spiricules that allow them to grasp fish. Osprey also have this adaptation. Bald Eagles have powerful talons. In one case, an eagle was able to fly off with the 6.8 kg (15 lb) carcass of a Mule Deer fawn.

Sometimes, if the fish is too heavy to lift, the eagle will be dragged into the water. It may swim to safety, but some eagles drown or succumb to hypothermia. Occasionally, Bald Eagles will pirate fish away from Ospreys and usually the smaller raptors will have to give up their prey, a practice known as kleptoparasitism.

National bird of the U.S.

Bald Eagle portrait

The Bald Eagle is the national bird of the United States of America. It is probably one of the country's most recognizable symbols, and appears on most of its official seals, including the Seal of the President of the United States.

Its national significance dates back to June 20, 1782, when the Continental Congress officially adopted the current design for the Great Seal of the United States including a Bald Eagle grasping arrows and an olive branch with its talons. Some states had earlier did so in 1778.

In 1784, after the end of the Revolutionary War, Benjamin Franklin wrote a famous letter to his daughter from Paris criticizing the choice and suggesting the Wild Turkey's character as a desirable trait:

For my own part I wish the Bald Eagle had not been chosen the Representative of our Country. He is a Bird of bad moral character. He does not get his Living honestly. You may have seen him perched on some dead Tree near the River, where, too lazy to fish for himself, he watches the Labour of the Fishing Hawk; and when that diligent Bird has at length taken a Fish, and is bearing it to his Nest for the Support of his Mate and young Ones, the Bald Eagle pursues him and takes it from him.

With all this Injustice, he is never in good Case but like those among Men who live by Sharping & Robbing he is generally poor and often very lousy. Besides he is a rank Coward: The little King Bird not bigger than a Sparrow attacks him boldly and drives him out of the District. He is therefore by no means a proper Emblem for the brave and honest country of America who have driven all the King birds from our Country...

I am on this account not displeased that the Figure is not known as a Bald Eagle, but looks more like a Turkey. For the Truth the Turkey is in Comparison a much more respectable Bird, and withal a true original Native of America . . . He is besides, though a little vain & silly, a Bird of Courage, and would not hesitate to attack a Grenadier of the British Guards who should presume to invade his Farm Yard with a red Coat on.

Despite Franklin's objections, the Bald Eagle remained the emblem of the United States. It can be found on both national seals and on the back of several coins (including the quarter dollar coin until 1999), with its head oriented towards the olive branch. Between 1916 and 1945, the Presidential Flag showed an eagle facing to its left (the viewer's right), which gave rise to the urban legend that the seal is changed to have the eagle face towards the olive branch in peace, and towards the arrows in wartime.&

Bald Eagle at Yellowstone National Park

Bald Eagles as religious objects

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 amongst Native Americans. Some Native Americans revere eagles as sacred religious objects, including the feathers and other parts and are often compared to the Bible and crucifix (AP 2004).

Eagle feathers are often used in traditional ceremonies and are used to honor noteworthy achievements and qualities such as exceptional leadership and bravery.

Despite modern and historic Native American practices of giving eagle feathers to non-Native Americans and Native American members of other tribes who have been deemed worthy, current eagle feather law stipulates that only individuals of certifiable Native American ancestry enrolled in a federally recognized tribe are legally authorized to obtain Bald or Golden Eagle feathers for religious or spiritual use (AP 2002) Attempts to extend this permitted use have met with resistance from members of federally recognized Native American tribes, who even under the permissive legislation sometimes have to wait for years before a good specimen can be procured for their use (AP 2004).


References

  • Template:IUCN2006 Database entry includes justification for why this species is of least concern
  • DeMeo, Antonia M. (1995): Access to Eagles and Eagle Parts: Environmental Protection v. Native American Free Exercise of Religion. Hastings Constitutional Law Quarterly 22(3): 771-813. HTML fulltext
  • Electronic Code of Federal Regulations (e-CFR) (1974): Title 50: Wildlife and Fisheries. Part 22 - Eagle Permits. HTML fulltext
  • Wink, M.; Heidrich, P. & Fentzloff, C. (1996): A mtDNA phylogeny of sea eagles (genus Haliaeetus) based on nucleotide sequences of the cytochrome b gene. Biochemical Systematics and Ecology 24: 783-791. Template:DOI PDF fulltext

Footnotes

  1. ↑ As explicitly stated by Audubon. However, the subspecific name he chose - washingtoniensis - means properly "from Washington (state)". There has been considerable confusion, with some authors changing it to washingtoni, "(George) Washington's", but the form as originally written is correct.
  2. ↑ The authors' reservations about using the generalized "2%" rate of molecular evolution have since proven to be well-founded.
  3. ↑ "http://www.snopes.com/history/american/turnhead.htm". http://www.snopes.com/history/american/turnhead.htm.

External links

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