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

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{{Taxobox
 
| color = RED
 
| name = Bald Eagle
 
| status = {{StatusLeastConcern}}
 
| image = Haliaeetus leucocephalus.jpg
 
| regnum = [[Animal]]ia
 
| phylum = [[Chordate|Chordata]]
 
| classis = [[Bird|Aves]]
 
| ordo = [[Falconiformes]]
 
| familia = [[Accipitridae]]
 
| genus = ''[[Haliaeetus]]''
 
| species = '''''H. leucocephalus'''''
 
| binomial = ''Haliaeetus leucocephalus''
 
| binomial_authority = ([[Carolus Linnaeus|Linnaeus]], [[1766]])
 
}}
 
  
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]].
 
 
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").
 
 
==Range and habitat==
 
A bald eagle's natural range includes most of North America, including most of Canada, all of the United States except Hawaii, and northern Mexico. Because it was hit hard by the [[DDT]] scare of the mid-twentieth century it is still slowly recovering its numbers; it 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.
 
 
==Description==
 
[[Image:bald.eagle.longshot.arp.500pix.jpg|200px|thumb|left|Bald Eagle at Combe Martin Wildlife and Dinosaur Park, North Devon, England]]
 
An immature bird has speckled brown [[feather]]s all over, the distinctive head and body [[plumage]] arriving 2–3 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 kg (12.8 lb), males weigh 4.1 kg (9 lb).
 
 
 
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.
 
 
==Behavior==
 
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 450 kg (one thousand pounds) or more.
 
 
Bald Eagles that are old enough to breed often return to the area where they were raised. They are more social than many other raptor species: an adult looking for a nesting site is more likely to select a location that contains other breeding Bald Eagles.
 
 
Bald Eagles are powerful fliers, and also soar on thermal convection currents. They are are long-lived, with reports of birds in captivity living to be 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 television.  What many recognize as the call of this species is actually the call of a [[Red-tailed Hawk]] dubbed into the film.
 
 
When breeding in the [[tundra]] biome, where there are no trees, eagles will nest directly on the ground.
 
 
==Reproduction==
 
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. Both the male and female of the pair take turns sitting on the eggs. The other parent will hunt for food or forage for nest material in the intervening time.
 
 
Third chicks are sometimes removed from nests to use in [[reintroduction]] programs in areas where the species has died out.
 
 
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.
 
 
==Diet==
 
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.
 
 
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.
 
 
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]].
 
 
==Eagles and humans==
 
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.
 
 
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.
 
 
==Rare vagrant==
 
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]].
 
 
==National Bird of the US==
 
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]].
 
 
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:
 
 
:''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 Cincinnati 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. Today it appears on many official seals in addition to the back of 25 cent coin.
 
 
==Gallery==
 
<gallery>
 
Image:Bald eagle.jpg|Adult
 
Image:Bald-eagle.jpg|Adult resting
 
Image:Haliaeetus_leucocephalus.jpeg|Adult
 
Image:A03 4663 1024x683.JPG|Female on nest with egg
 
Image:Bald Eagle.jpg|Adult in a treetop
 
Image:Aa 2006 03 18 bald eagle immature 01 360x300.jpg|Immature
 
</gallery>
 
 
==External links==
 
{{commons|Haliaeetus leucocephalus}}
 
*[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
 
*[http://www.greatseal.com/symbols/turkey.html Ben Franklin - the Eagle and the Turkey]
 
*[http://www.nwf.org/wildlife/baldeagle/nationalbird.cfm?photo=1 Eagle vs. Turkey]
 
*[http://www.infotecbusinesssystems.com/wildlife/default.asp Live web cam of a Bald Eagle nest in British Columbia]
 
*[http://www.nu.com/eagles/default.asp Live web cam of a Bald Eagle nest in Massachusetts]
 
*[http://www.baldeagleinfo.com/ Bald Eagle Information]
 
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[[Category:Eagles]]
 
 
[[cs:Orel bělohlavý]]
 
[[da:Hvidhovedet havørn]]
 
[[de:Weißkopfseeadler]]
 
[[eo:Blankkapa maraglo]]
 
[[fi:Valkopäämerikotka]]
 
[[fr:Pygargue à tête blanche]]
 
[[ja:ハクトウワシ]]
 
[[nl:Amerikaanse zeearend]]
 
[[pl:Bielik amerykański]]
 
[[pt:Águia de cabeça branca]]
 
[[sv:Vithövdad havsörn]]
 

Revision as of 12:56, 5 May 2006