Wikipedysta:Adrian 1111/brudnopis 2


Wikipedysta:Adrian 1111/brudnopis 2 w encyklopedii

Z Wikipedii, wolnej encyklopedii < Wikipedysta:Adrian 1111 Przejdź do nawigacji Przejdź do wyszukiwania

Pożywienie | edytuj kod

Młody osobnik z łososiem, Katmai National Park

Bielik to oportunistyczny mięsożerca, który może polować na różne ofiary. Ryby zwykle składają się na większość diety tych ptaków, na całym obszarze występowania[1]. W 20 badaniach dotyczących nawyków żywieniowych, ryby stanowiły 56% pożywienia gniazdujących bielików, ptaki 28%, ssaki 14%, inne ofiary 2%[2]. Do zakresu zwierzyny na które polują bieliki zalicza się ponad 200 gatunków, co jest wartością o wiele większą niż u odpowiednika tego ptaka na Starym Kontynencie, bielika zwyczajnego. Pomimo znacznie niższej populacji w stosunku do innych szponiastych ptaków Ameryki Północnej, bielik amerykański zajmuje drugie miejsce, niewiele za myszołowem rdzawosternym, pod względem liczby odnotowanych gatunków na które poluje[3][2][4][5].

W południowo-wschodniej Alasce ryby stanowią około 66% całorocznej diety bielików i 78% zdobyczy przyniesionej do gniazda przez rodziców[6]. Ryby, dla bielików żyjących w ujściu rzeki Columbia w Oregonie, stanowiły 90% pożywienia[7]. W diecie bielika odnotowano co najmniej 100 gatunków ryb[4]. Na północno-zachodnim Pacyfiku odbywające tarło pstrągi i łososie stanowią większość diety bielików amerykańskich od późnego lata do jesieni[8]. Bieliki południowo-wschodniej Alaski w dużej mierze polują na gorbusza (Oncorhynchus gorbuscha), kiżucza (O. kisutch) i, bardziej regionalnie, nerkę (O. nerka). Czawyczą (O. tshawytscha), ze względu na duży rozmiar (osobniki dorosłe ważą od 12 do 18 kg.) prawdopodobnie żywią się wyłącznie jako padliną[6]. W ujściach rzek i na płytkich wybrzeżach południowej Alaski ważną część diety stanowią również śledzie pacyficzne (Clupea pallasii), dobijaki pacyficzne (Ammodytes hexapterus) i olakony (Thaleichthys pacificus)[9].


W ujściu rzeki Columbia w stanie Oregon najważniejszymi gatunkami łownymi były Catostomus macrocheilus (17,3% ofiar), aloza amerykańska (Alosa sapidissima; 13%) i karp (Cyprinus carpio; 10,8%)[7]. Bieliki żyjące w Zatoce Chesapeake w Maryland, przetrwały na pożywieniu składającym się w dużej mierze z Dorosoma cepedianum, Dorosoma petenense i moronie białej (Morone chrysops)[10]. Stwierdzono, że bieliki florydyjskie żerują na sumach, najczęściej na sumikach karłowatych (Ameiurus nebulosus) i wszelkich gatunkach z rodzaju Ictalurus, a także na mugilowate, pstrągi, belonowate i węgorzokształtne[11][12][13]. Zimujące orły na rzece Platte w stanie Nebraska żerują głównie na Dorosoma cepedianum i karpiach[14]. Z obserwacji prowadzonych przy rzece Columbia wynika, że 58% ryb zostało złapanych żywych przez orła, 24% zostało złowionych jako padlina, a 18% zostało przechwyconych od innych zwierząt[7].

Feeding on catfish and other various fishes. Painted by John James Audubon

Nawet bieliki żyjące w stosunkowo suchych regionach nadal zwykle polegają głównie na pożywieniu rybnym. W Sonorze (Meksyk) i Arizonie odpowiednio 77% i ponad 73% resztek ofiar w gniazdach pochodziło od ryb, głównie różnych sumów i pstrągów tęczowych (Oncorhynchus mykiss). Ryby, na które polują bieliki, są często dość duże.

When experimenters offered fish of different sizes in the breeding season around Lake Britton in California, fish measuring 34 do 38 cm (13 do 15 in) were taken 71.8% of the time by parent eagles while fish measuring 23 do 27,5 cm (9,1 do 10,8 in) were chosen only 25% of the time.[15] At nests around Lake Superior, the remains of fish (mostly suckers) were found to average 35,4 cm (13,9 in) in total length.[16] In the Columbia River estuary, most preyed on by eagles were estimated to measure between 30 i 60 cm (12 i 24 in) in length, and carp flown with (laboriously) were up to 86 cm (34 in) in length.[7] Much larger marine fish such as Pacific halibut (Hippoglossus stenolepis) and lemon sharks (Negaprion brevirostris) have been recorded among bald eagle prey though probably are only taken as young, as small, newly mature fish or as carrion.[5][17]

A bald eagle on a whale carcass.

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.[10] Bald eagles also regularly exploit water turbines which produce battered, stunned or dead fish easily consumed.[18] 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.[6] 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.[19]

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.[7][20] Overall, birds are the most diverse group in the bald eagle's prey spectrum, with 200 prey species recorded.[3][4][5] 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.[21] Preferred avian prey includes grebes, alcids, ducks, gulls, coots, herons, egrets, and geese.[22]

A nesting colony of kittiwakes and murres, with a juvenile bald eagle

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.[11][7] American herring gull (Larus smithsonianus) are the favored avian prey species for eagles living around Lake Superior.[16] Larger waterbirds are occasionally prey as well, with wintering emperor geese (Chen canagica) and snow geese (C. caerulescens), which gather in large groups, sometimes becoming regular prey.[23][24] Other large waterbirds hunted at least occasionally by bald eagles have included adults of common loons (Gavis immer),[25] great black-backed gulls (Larus marinus),[26] sandhill cranes (Grus canadensis),[27] great blue herons (Ardea herodias),[2] Canada geese (Branta canadensis),[10] brown pelicans (Pelecanus occidentalis),[12] and fledgling American white pelicans (P. erythrorhynchos).[28] 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 preying on such seabirds at all ages, from eggs to mature adults, and can effectively cull large portions of a colony.[29]

Along some portions of the North Pacific coastline, bald eagles which had historically preyed 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 precipitous population declines, causing concern for seabird conservation.[30] Because of this more extensive predation, some biologist have expressed concern that murres are heading for a "conservation collision" due to heavy eagle predation.[29] 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.[31] 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.[29] Bird prey may occasionally be attacked in flight, with prey up to the size of Canada geese attacked and killed in mid-air.[22] Unprecedented photographs of a bald eagle unsuccessfully attempting to prey on a much larger adult trumpeter swan (Cygnus buccinator) in mid-flight were taken recently.[32] While adults often actively prey on waterbirds, congregated wintering waterfowl are frequently exploited for carcasses to scavenge by immature eagles in harsh winter weather.[33] 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. Nine species each of other accipitrids and owls are known to have been preyed upon by bald eagles. Owl prey species have ranged in size from western screech-owls (Megascops kennicotti) to snowy owls (Bubo scandiacus).[3][4][5][34] Larger diurnal raptors known to have fallen victim to bald eagles have included red-tailed hawks (Buteo jamaicensis),[35] peregrine falcons (Falco peregrinus),[36] northern goshawks (Accipiter gentilis),[37] ospreys (Pandion haliaetus)[38] and black (Coragyps atratus) and turkey vultures (Cathartes aura).[39]

In Skagit Valley, Washington, United States

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 subadult beavers are sometimes attacked. In the Chesapeake Bay area, bald eagles are reportedly the main natural predators of raccoons.[40][41] Other relatively large mammalian prey known to be taken by bald eagles (at least rarely) as adults include Virginia opossums (Didelphis virginiana), nine-banded armadillos (Dasypus novemcinctus), red and arctic foxes (Vulpes vulpes & Vulpes lagopus) and striped skunks (Mephitis mephitis).[42][43] Even an adult bobcat (Lynx rufus) has been recorded amongst their prey, although this may have been scavenged.[44] Where available, seal colonies can provide much food. On Protection Island, Washington, they commonly feed on harbor seal (Phoca vitulina) afterbirths, still-borns and sickly seal pups.[45] 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.[46] 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 as prairie dogs (Cynomys) and jackrabbits (Lepus). Like the golden eagle, bald eagles are capable of attacking jackrabbits and hares of nearly any size[11][47] Together with the golden eagle, bald eagles are occasionally accused of preying on 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 detriment to human livelihoods.[48] 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.[49]

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.[11] 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 do 17,1 cm (3,6 do 6,7 in).[50] Similarly, many turtles were recorded in the diet in the Chesapeake Bay.[51] Snakes are also taken occasionally, especially partially aquatic ones, as are amphibians and crustaceans (largely crayfish and crabs).[12][7]

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.[52] Bald eagles have powerful talons and have been recorded flying with a 6,8 kg (15 lb) mule deer (Odocoileus hemionus) fawn.[53] This feat is the record for the heaviest load carrying ever verified for a flying bird.[54] 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.[55] 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, in some cases pulling the catch along to the shore as it swims,[56] 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.[12][24] 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.[23] 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.[12] 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.[57][58][59] 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 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.[23]

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 do 3 kg (2,2 do 6,6 lb) and most waterbirds preyed weighing 0,2 do 2,7 kg (0,44 do 5,95 lb).[6][24][60] On the other hand, some salmon, carp and marine fish, mammals such as deer fawn and lambs and birds such as swans taken by bald eagles are likely to have been up to at least twice the bald eagles' own size (even if the eagle was unable to fly with it).[3][2][4] They obtain much of their food as carrion or via a practice known as kleptoparasitism, by which they steal prey away from other predators. Due to their dietary habits, bald eagles are frequently viewed in a negative light by humans.[11] 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.[61][62] 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.[23] Bald eagles also may sometimes feed on material scavenged or stolen from campsites and picnics, as well as garbage dumps (dump usage is habitual mainly in Alaska).[63]

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.[63] 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.[64] 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).[65] 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.[23] Wintering bald and golden eagles in Utah both sometimes won conflicts, though in one recorded instance a single bald eagle successfully displaced two consecutive golden eagles from a kill.[66] 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.[65][67] Due to this, bald eagles often outnumber golden eagles at attractive food sources.[65] 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. Similarly, both eagle species have been recorded, via video-monitoring, to feed on gut piles and carcasses of white-tailed deer (Odocoileus virginianus) in remote forest clearings in the eastern Appalachian Mountains without apparent conflict.[65] Bald eagles as frequently mobbed by smaller raptors, due to their infrequent but unpredictable tendency to hunt other birds of prey.[66] 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.[23][68] 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.[69][70] 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.[12] Healthy adult bald eagles are not preyed on in the wild and are thus considered apex predators.[71]

Przypisy | edytuj kod

  1. "Bald Eagle Fact Sheet, Lincoln Park Zoo". Lpzoo.org. Retrieved on 2012-08-22.
  2. a b c d Stalmaster, M.V. (1987). The Bald Eagle. Universe Books, New York.
  3. a b c d Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie Palmer
  4. a b c d e Sherrod, S. K. (1978). Diets of North American Falconiformes. Raptor Res, 12(3/4), 49-121.
  5. a b c d Collins, P. W., Guthrie, D. A., Rick, T. C., & Erlandson, J. M. (2005). Analysis of prey remains excavated from an historic bald eagle nest site on San Miguel Island, California. In Proceedings of the Sixth California Islands Symposium. Arcata, CA: Institute for Wildlife Studies (pp. 103-120).
  6. a b c d Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie Armstrong
  7. a b c d e f g Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie Watson2
  8. Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie Alaska
  9. Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie Armstrong2
  10. a b c Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie Mersmann
  11. a b c d e Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie Travsky
  12. a b c d e f Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie FPL
  13. Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie j5
  14. Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie j15
  15. Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie Jenkins
  16. a b Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie Kozie
  17. Ofelt, C. H. (1975). Food habits of nesting Bald Eagles in southeast Alaska. The Condor, 77(3), 337-338.
  18. D.C. Jr.D.C.J. Delong D.C. Jr.D.C.J., Effects of food on Bald Eagle distribution and abundance on the northern Chesapeake Bay: an experimental approach, „Master's Thesis”, 1990 .
  19. Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie Stalmaster1
  20. Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie Brisbin, Jr.Mowbray2002
  21. Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie Swenson, J. E. 1986
  22. a b Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie RaptorsWorld
  23. a b c d e f Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie BNA
  24. a b c Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie Gill
  25. Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie j6
  26. T.P.T.P. Good T.P.T.P., Great Black-backed Gull- Behavior- Birds of North America Online, Cornell Lab of Ornithology [dostęp 2013-01-07] .
  27. Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie Wood
  28. Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie b4
  29. a b c Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie Henderson
  30. Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie sciencedaily
  31. Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie Nocturnal
  32. Bald Eagle attacking a Trumpter Swan. Utahbirds.org. Retrieved on 2012-08-21.
  33. Griffin, C. R., T. S. Baskett, and R. D. Sparrowe. 1982. Ecology of Bald Eagles wintering near a waterfowl concentration. Rep. no. 247. U.S. Fish Wildl. Serv. Washington, D.C.
  34. Jackman, R. E., Hunt, W. G., Jenkins, J. M., & Detrich, P. J. (1999). Prey of nesting bald eagles in northern California. Journal of Raptor Research, 33(2), 87-96.
  35. Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie Leschner
  36. Anthony, R. G., Estes, J. A., Ricca, M. A., Miles, A. K., & Forsman, E. D. (2008). Bald eagles and sea otters in the Aleutian archipelago: indirect effects of trophic cascades. Ecology, 89(10), 2725-2735.
  37. Cartron, J. L. E. (Ed.). (2010). Raptors of New Mexico. UNM Press.
  38. Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie MacDonald
  39. Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie Coleman
  40. Birds of North America Online, Bna.birds.cornell.edu [dostęp 2012-06-27] .
  41. Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie Beaver
  42. Mabie, D. W., Merendino, M. T., & Reid, D. H. (1995). Prey of nesting bald eagles in Texas. Journal of Raptor Research, 29(1), 10-14.
  43. Grubb, T. G. (1995). Food habits of bald eagles breeding in the Arizona desert. The Wilson Bulletin, 258-274.
  44. Mersmann, T. J. (1989). Foraging ecology of Bald Eagles on the northern Chesapeake Bay with an examination of techniques used in the study of Bald Eagle food habits. (Doctoral dissertation, Virginia Tech).
  45. Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie Hayward
  46. Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie j12
  47. Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie Jones
  48. Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie ICWDM
  49. Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie McEneaney
  50. Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie Wetlands
  51. Clark, W. S. (1982). Turtles as a food source of nesting bald eagles in the Chesapeake Bay region. Journal of Field Ornithology, 53(1), 49-51.
  52. Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie Terres
  53. Birds of prey — Diet & Eating Habits, Seaworld.org [dostęp 2009-03-03] [zarchiwizowane z adresu .zarchiwizowano?
  54. Amazing Bird Records, Trails.com [dostęp 2012-07-20] .
  55. Gripping Strength of an Eagle – Understanding psi 101, Hawkquest [dostęp 2012-07-20] .
  56. SteveS. Potts SteveS., The Bald Eagle, Capstone, 1999, ISBN 978-0-7368-8483-9 .data dostępu?
  57. Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie Cornell
  58. Edwards, C.C. (1969). Winter behavior and population dynamics of American eagles in Utah. PhD Thesis. Brigham Young University. Provo, UT.
  59. Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie j25
  60. Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie Newsome
  61. Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie Todd
  62. Harmata, A. R. 1984. Bald Eagles of the San Luis valley, Colorado: their winter ecology and spring migration. Phd Thesis. Montana State University. Bozeman.
  63. a b Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie Sherrod
  64. Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie j14
  65. a b c d Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie Watson
  66. a b Sabine, N., & Gardner, K. (1987). Agonistic encounters between Bald Eagles and other raptors wintering in west central Utah. Journal of Raptor Research, 21, 118-120.
  67. Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie Bio
  68. Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie j13
  69. Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie j7
  70. Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie j8
  71. Błąd w przypisach: Błąd w składni elementu <ref>. Brak tekstu w przypisie o nazwie r6
Na podstawie artykułu: "Wikipedysta:Adrian 1111/brudnopis 2" pochodzącego z Wikipedii
OryginałEdytujHistoria i autorzy