The African civet is primarily nocturnal and spends the day sleeping in dense vegetation, but wakes up at sunset. It is a solitarymammal with a unique coloration: the black and white blotches covering its coarse pelage and rings on the tail are an effective cryptic pattern. The black bands surrounding its eyes closely resemble those of the raccoon. Other distinguishing features are its disproportionately large hindquarters and its erectile dorsal crest. It is an omnivorous generalist, preying on small vertebrates, invertebrates,
eggs, carrion, and vegetable matter. It is one of the few carnivores
capable of eating toxic invertebrates such as termites and millipedes.[3][4] It detects prey primarily by smell and sound rather than by sight. It is the sole member of its genus.[5]
A 1969 study noted that this civet showed enough differences from the rest of the viverrines in terms of dentition to be classified under its own genus.[11]
In
2006, it was estimated that about 9,400 African civets are hunted yearly
in the Nigerian part and more than 5,800 in the Cameroon part of the Cross-Sanaga-Bioko coastal forests.[34]
Skins and skulls of African civets were found in 2007 at the Dantokpa Market
in southern Benin, where it was among the most expensive small
carnivores. Local hunters considered it a rare species, indicating that
the population declined due to hunting for trade as bushmeat.[35]
The generic nameCivettictis is a fusion of the French word civette and the Greek word ictis, meaning "weasel". The specific namecivetta and the common name "civet" come from the French civette or the Arabiczabād or sinnawr al-zabād ("civet cat").[13]
The African civet has a coarse and wiry fur
that varies in colour from white to creamy yellow to reddish on the
back. The stripes, spots, and blotches are deep brown to black.
Horizontal lines are prominent on the hind limbs, spots are normally
present on its midsection and fade into vertical stripes above the
forelimbs. Its muzzle is pointed, ears small and rounded. A black band
stretches across its small eyes, and two black bands are around its
short broad neck. Following the spine of the animal extending from the
neck to the base of the tail is the erectile dorsal crest. The hairs of the erectile crest are longer than those of the rest of the pelage.[5]
The sagittal crest of its skull is well-developed providing a large area for attachment of the temporal muscle. The zygomatic arch is robust and provides a large area for attachment of the masseter muscle. This musculature and its strong mandible give it a powerful bite. Its dental formula is 3.1.4.23.1.4.2. Its black
paws are compact with hairless soles, five digits per manus
in which the first toe is slightly set back from the others. Its long,
curved claws are semi-retractile. Its head-and-body length is 67–84 cm
(26–33 in), with a 34–47 cm (13–19 in) long tail and a weight range from
7 to 20 kg (15 to 44 lb). Females are smaller than males.[5]
It is the largest viverrid in Africa.[15] Its shoulder height averages 40 cm (16 in).[citation needed]
Both male and female have perineal and anal glands, which are bigger in males.[5] The perineal glands are located between the scrotum and the penis in males, and between the anus and the vulva in females.[16]
African civets typically sleep during the day in the tall grasses
near water sources in central and southern Africa. It often inhabits
savannahs, forests, and sometimes near rivers as the tall grasses and
thickets present provide them with necessary cover
African civets deposit their feces in large piles called latrines, or specifically "civetries".[16][23] The latrines are characterized by fruits, seeds, exoskeletons of insect and millipede rings, and occasionally clumps of grass.[24] The role of civet latrines as a mechanism of seed dispersal and forest regeneration is still being researched.[25][26]
African civets are typically solitary creatures. They use their
perineal gland secretion to mark their territories around their
civetries. These markings typically follow common routes and paths and
lie within 100 meters of civetries 96.72% of the time.[27]
If an African civet feels threatened, it raises its dorsal crest
to make itself look larger and thus more formidable and dangerous to
attack. This behavior is a predatory defense.[28]
Green grass is also frequently found in feces, and this seems to be linked to the eating of snakes and amphibians.[31]
Captive females are polyestrous.[32]Mating lasts 40 to 70 seconds.[16]
In Southern Africa, African civets probably mate from October to
November, and females give birth in the rainy season between January and
February.[30]
The average lifespan of a captive African civets is 15 to 20
years. Females create a nest which is normally in dense vegetation and
commonly in a hole dug by another animal. Female African civets
normally give birth to one to four young. The young are born in advanced
stages compared to most carnivores.[clarification needed]
They are covered in a dark, short fur and can crawl at birth. The young
leave the nest after 18 days but are still dependent on the mother for
milk and protection for another two months.[33]
In
2006, it was estimated that about 9,400 African civets are hunted yearly
in the Nigerian part and more than 5,800 in the Cameroon part of the
The African civet has historically been hunted for the secretion of perineal glands. This secretion is a white or yellow waxy substance called civetone, which has been used as a basic ingredient for many perfumes for hundreds of years.[5]
In Ethiopia, African civets are hunted alive, and are kept in small
cages. Most die within three weeks after capture, most likely due to
stress. Extraction of the civetone is cruel and has been criticised by
animal rights activists.[36]
The golden eagle (Aquila chrysaetos) is a bird of prey living in the Northern Hemisphere. It is the most widely distributed species of eagle. Like all eagles, it belongs to the family Accipitridae. They are one of the best-known birds of prey in the Northern Hemisphere. These birds are dark brown, with lighter golden-brown plumage on their napes.
Immature eagles of this species typically have white on the tail and
often have white markings on the wings. Golden eagles use their agility
and speed combined with powerful feet and large, sharp talons to hunt a
variety of prey, mainly hares, rabbits, and marmots and other ground squirrels.[4]
Golden eagles maintain home ranges or territories that may be as large as 200 km2 (77 sq mi). They build large nests
in cliffs and other high places to which they may return for several
breeding years. Most breeding activities take place in the spring; they
are monogamous and may remain together for several years or possibly for
life. Females lay up to four eggs,
and then incubate them for six weeks. Typically, one or two young
survive to fledge in about three months. These juvenile golden eagles
usually attain full independence in the fall, after which they wander
widely until establishing a territory for themselves in four to five
years.
Once widespread across the Holarctic, it has disappeared from many areas that are heavily populated by humans. Despite being extirpated from or uncommon in some of its former range, the species is still widespread, being present in sizeable stretches of Eurasia, North America, and parts of North Africa. It is the largest and least populous of the five species of true accipitrid to occur as a breeding species in both the Palearctic and the Nearctic.[5]
For centuries, this species has been one of the most highly regarded birds used in falconry.
Because of its hunting prowess, the golden eagle is regarded with great
mystic reverence in some ancient, tribal cultures. It is one of the
most extensively studied species of raptor in the world in some parts of
its range, such as the Western United States and the Western Palearctic.
This species was first described by Carl Linnaeus in his landmark 1758 10th edition of Systema Naturae as Falco chrysaetos.[6]
Since birds were grouped largely on superficial characteristics at that
time, many species were grouped by Linnaeus into the genus Falco. The type locality was given simply as "Europa"; it was later restricted to Sweden. It was moved to the new genus Aquila by French ornithologistMathurin Jacques Brisson in 1760.[7]Aquila is Latin for "eagle", possibly derived from aquilus, "dark in colour" and chrysaetos is Ancient Greek for the golden eagle from khrusos, "gold" and aetos, "eagle".[8]
The golden eagle is part of a broad group of raptors called
"booted eagles" which are defined by the feature that all species have
feathering over their tarsus,
unlike many other accipitrids which have bare legs. Included in this
group are all species described as "hawk eagles" including the genera Spizaetus and Nisaetus, as well as assorted monotypical genera such as Oroaetus, Lophaetus, Stephanoaetus, Polemaetus, Lophotriorchis and Ictinaetus.
The genus Aquila is distributed across every continent but for South America and Antarctica.
Up to 20 species have been classified in the genus, but more recently
the taxonomic placement of some of the traditional species has been
questioned. Traditionally, the Aquila eagles have been grouped
superficially as largish, mainly brownish or dark-colored booted eagles
that vary little in transition from their juvenile to their adult
plumages. Genetic research has recently indicated the golden eagle is
included in a clade with Verreaux's eagle in Africa as well as the Gurney's eagle (A. gurneyi) and the wedge-tailed eagle
(clearly part of an Australasian radiation of the lineage). This
identification of this particular clade has long been
suspected based on
similar morphological characteristics amongst these large-bodied
species.[5] More surprisingly, the smaller, much paler-bellied sister species Bonelli's eagle (A. fasciatus) and African hawk-eagle (A. spilogaster), previously included in the genus Hieraaetus,
have been revealed to be genetically much closer to the Verreaux's and
golden eagle lineage than to other species traditionally included in the
genus Aquila.[4][9][10] Other largish Aquila species, the eastern imperial, the Spanish imperial, the tawny and the steppe eagles,
are now thought to be separate, close-knit clade, which attained some
similar characteristics to the prior clade via convergent evolution.[9][10]
Genetically, the "spotted eagles" (A. pomarina, hastata and clanga), have been discovered to be more closely related to the long-crested eagle (Lophaetus occipitalis) and the black eagle (Ictinaetus malayensis), and many generic reassignments have been advocated.[9][11] The genus Hieraaetus, including the booted eagle (H. pennatus), little eagle (H. morphnoides) and Ayres's hawk-eagle (H. ayresii), consists of much smaller species, that are in fact smallest birds called eagles outside of the unrelated Spilornis serpent-eagle genus. This genus has recently been eliminated by many authorities and is now occasionally also included in Aquila, although not all ornithological unions have followed this suit in this re-classification.[4][10][12] The small-bodied Wahlberg's eagle (H. wahlbergi) has been traditionally considered a Aquila
species due to its lack of change from juvenile to adult plumage and
brownish color but it is actually genetically aligned to the Hieraaetus lineage.[9][13]Cassin's hawk-eagle (H. africanus) is also probably closely related to the Hieraaetus group rather than the Spizaetus/Nisaetus "hawk-eagle" group (in which it was previously classified) which is not known to have radiated to Africa.[14]
There are six extant subspecies of golden eagle that differ slightly in size and plumage. Individuals of any of the subspecies are somewhat variable and the differences between the subspecies are clinal, especially in terms of body size. Other than these characteristics, there is little variation across the range of the species.[15] Some recent studies have gone so far as to propose that only two subspecies be recognized based on genetic markers: Aquila chrysaetos chrysaetos (including A. c. homeyeri) and A. c. canadensis (including A. c. japonica, A. c. daphanea and A. c. kamtschatica).[16]
The golden eagle is a very large raptor, 66 to 102 centimetres (26 to
40 in) in length. Its wings are broad and the wingspan is 1.8 to 2.34
metres (5 ft 11 in to 7 ft 8 in).[33][15][34][35] The wingspan of golden eagles is the fifth largest among living eagle species.[15]Females are larger than males,
with a bigger difference in larger subspecies. Females of the large
Himalayan golden eagles are about 37% heavier than males and have nearly
9% longer wings, whereas in the smaller Japanese golden eagles, females
are only 26% heavier with around 6% longer wings.[4][36] In the largest subspecies (A. c. daphanea), males and females weigh typically 4.05 and 6.35 kg (8.9 and 14.0 lb), respectively. In the smallest subspecies, A. c. japonica, males
weigh 2.5 kg (5.5 lb) and females 3.25 kg (7.2 lb).[4] In the species overall, males average around 3.6 kg (7.9 lb) and females around 5.1 kg (11 lb).[37] The maximum size of golden eagles is debated. Large subspecies are the heaviest representatives of the genus Aquila
and this species is on average the seventh-heaviest living eagle
species. The golden eagle is the second heaviest breeding eagle in North
America,
Europe and Africa and the fourth heaviest in Asia.[5][15] For some time, the largest known mass authenticated for a wild female was the specimen from the A. c. chrysaetos subspecies which weighed around 6.7 kg (15 lb) and spanned 2.55 m (8 ft 4 in) across the wings.[21]
American golden eagles are typically somewhat smaller than the large
Eurasian species, but a massive female that was banded and released in
2006 around Wyoming's Bridger-Teton National Forest became the heaviest wild golden eagle on record, at 7.7 kg (17 lb).[38]
Captive birds have been measured with a wingspan of 2.81 m (9 ft 3 in)
and a mass of 12.1 kg (27 lb), though this mass was for an eagle bred
for falconry, which tend to be unnaturally heavy.[21]
The standard measurements of the species include a wing chord length of 52–72 cm (20–28 in), a tail length of 26.5–38 cm (10.4–15.0 in) and a tarsus length of 9.4–12.2 cm (3.7–4.8 in).[15] The culmen
(upper ridge of beak) reportedly averages around 4.5 cm (1.8 in), with a
range of 3.6 to 5 cm (1.4 to 2.0 in). The bill length from the gape measures around 6 cm (2.4 in).[39][40] The long, straight and powerful hallux-claw (hind claw) can range from 4.5 to 6.34 cm (1.77 to 2.50 in), about one centimetre longer than in a bald eagle and a little more than one centimetre less than a harpy eagle.[26][41][42]
Adults of both sexes have similar plumage and are primarily dark
brown, with some grey on the inner wing and tail, and a paler, typically
golden colour on the back of the crown and nape that gives the species
its common name.
Juvenile golden eagles are similar to adults but tend to be darker, appearing black on the back especially in East Asia.
They have a less faded colour. Young birds are white for about
two-thirds of their tail length, ending with a broad, black band.[36] Occasionally, juvenile eagles have white patches on the remiges
at the bases of the inner primaries and the outer secondaries, forming a
crescent marking on the wings which tends to be divided by darker
feathers.[4][46]
Rarely, juvenile birds may have only traces of white on the tail.
Compared to the relatively consistently white tail, the white patches on
the wing are extremely variable; some juveniles have almost no white
visible. Juveniles of less than 12 months of age tend to have
the most
white in their plumage.[44]
By their second summer, the white underwing coverts are usually
replaced by a characteristic rusty brown colour. By the third summer,
the upper-wing coverts are largely replaced by dark brown feathers,
although not all feathers moult at once which leaves many juvenile birds
with a grizzled pattern. The tail follows a similar pattern of
maturation to the wings.[44][46] Due to the variability between individuals, juvenile eagles cannot be reliably aged by sight alone.[47] Many golden eagles still have white on the tail during their first attempt at nesting.[48] The final adult plumage is not fully attained until the birds are between 5+1⁄2 and 6+1⁄2 years old.[47]
This species moults gradually beginning in March or April until
September or October each year. Moulting usually decreases in winter.
Moult of the contour feathers begins on the head and neck region and
progresses along the feather tracts in a general front-to-back
direction. Feathers on head, neck, back and scapulars may be replaced
annually. With large feathers of the wing and tail, moult begins with
the innermost feathers and proceeds outwards in a straightforward manner
known as "descendant" moult.[44]
While many accipitrids are not known for their strong voices, golden
eagles have a particular tendency for silence, even while breeding.[17]
That being said, some vocalization has been recorded, usually centering
around the nesting period. The voice of the golden eagle is considered
weak, high, and shrill, has been called "quite pathetic" and
"puppy-like", and seems incongruous with the formidable size and nature
of the species.[15]
Most known vocalisations seem to function as contact calls between
eagles, sometimes adults to their offspring, occasionally territorial
birds to intruders and rarely between a breeding pair. In western Montana, nine distinct calls were noted: a chirp, a seeir, a pssa, a skonk, a cluck, a wonk, a honk and a hiss.[49]
Golden eagles are sometimes considered the best fliers among eagles and perhaps among all raptorial birds.[17] They are equipped with broad, long wings with somewhat finger-like indentations on the tips of the wing.[15] Golden eagles are unique among their genus in that they often fly in a slight dihedral, which means the wings are often held in a slight, upturned V-shape.[15] When they need to flap, golden eagles appear at their most laboured, but this is less common than soaring or gliding––.[4] Flapping flight usually consists of 6–8 deep wing-beats, interspersed with 2–3 second glides.[4] While soaring, the wings and tail
are held in one plane with the primary tips often spread.[50] A typical, unhurried soaring speed in golden eagles is around 45–52 kilometres per hour (28–32 mph).[51] When hunting or displaying, the golden eagle can glide very fast, reaching speeds of up to 190 kilometres per hour (120 mph).[4][50]
When stooping (diving) in the direction of prey or during territorial
displays, the eagle holds its legs up against its tail, and holds its
wings tight and partially closed against its body. When diving after
prey, a golden eagle can reach 240 to 320 kilometres per hour (150 to
200 mph). Although less agile and manoeuvrable, the golden eagle is
apparently quite the equal and possibly even the superior of the peregrine falcon's stooping and gliding speeds.[5][52] This makes the golden eagle one of the two fastest living animals.[21]
Although most flight in golden eagles has a clear purpose (e.g.,
territoriality, hunting), some flights, such as those by solitary birds
or between well-established breeding pairs, seem to be play.[5][17][53]
Size readily distinguishes this species from most other raptors when
it is seen well. Most other raptors are considerably smaller. Buteo
hawks, which are perhaps most similar to the golden eagle in structure
among the species outside of the "booted eagle" group, are often counted
among the larger very common raptors. However, a mid-sized Buteo is dwarfed by a golden eagle, as an adult female eagle has about double the wingspan and about five times the weight. Buteos are also usually distinctly paler below, although some species occur in dark morphs which can be
Size readily distinguishes this species from most other raptors when
it is seen well. Most other raptors are considerably smaller. Buteo
hawks, which are perhaps most similar to the golden eagle in structure
among the species outside of the "booted eagle" group, are often counted
among the larger very common raptors. However, a mid-sized Buteo is dwarfed by a golden eagle, as an adult female eagle has about double the wingspan and about five times the weight. Buteos are also usually distinctly paler below, although some species occur in dark morphs which can be darker than a golden eagle.[15][54] Among raptorial birds that share the golden eagle's range, only some Old World vultures and the California condor
are distinctly
larger, with longer, broader wings, typically held more
evenly in a slower, less forceful flight; they often have dramatically
different colour patterns. In North America, the golden eagle may be
confused with the turkey vulture
from a great distance, as it is a large species that, like the golden
eagle, often flies with a pronounced dihedral. The turkey vulture can be
distinguished by its less controlled, forceful flying style (they
frequently rock back and forth unsteadily in even moderate winds) and
its smaller, thinner body, much smaller head and, at closer range, its
slaty black-brown colour and silvery wing secondaries.[55] Compared to Haliaeetus eagles, the golden eagle has
wings that are only somewhat more slender but are more hawk-like and lack the flat, plank-like wing positioning seen in the other genus.[55] Large northern Haliaeetus
species usually have a larger bill and larger head which protrudes more
distinctly than a golden eagle's in flight. The tail of the golden
eagle is longer on average than those of Haliaeetus eagles,
appearing to be two or three times the length of the head in soaring
flight, whereas in the other eagles the head is often more than twice
the length of the tail.[55] Confusion is most likely between juvenile Haliaeetus and golden eagles, as the adult golden has a more solidly golden-brown coloration and all Haliaeetus eagles have obvious distinctive plumages as adults. Haliaeetus
eagles are often heavily streaked in their juvenile phase. Juvenile
golden eagles can have large patches of white on their wings and tail
that are quite different from the random, sometimes large and
splotchy-looking distribution of white typical of juvenile Haliaeetus.[15][55]
darker than a golden eagle.[15][54] Among raptorial birds that share the golden eagle's range, only some Old World vultures and the California condor
are distinctly larger, with longer, broader wings, typically held more
evenly in a slower, less forceful flight; they often have dramatically
different colour patterns. In North America, the golden eagle may be
confused with the turkey vulture
from a great distance, as it is a large species that, like the golden
eagle, often flies with a pronounced dihedral. The turkey vulture can be
distinguished by its less controlled, forceful flying style (they
frequently rock back and forth unsteadily in even moderate winds) and
its smaller, thinner body, much smaller head and, at closer range, its
slaty black-brown colour
and silvery wing secondaries.[55] Compared to Haliaeetus eagles, the golden eagle has wings that are only somewhat more slender but are more hawk-like and lack the flat, plank-like wing positioning seen in the other genus.[55] Large northern Haliaeetus
species usually have a larger bill and larger head which protrudes more
distinctly than a golden eagle's in flight. The tail of the golden
eagle is longer on average than those of Haliaeetus eagles,
appearing to be two or three times the length of the head in soaring
flight, whereas in the other eagles the head is often more than twice
the length of the tail.[55] Confusion is most likely between juvenile Haliaeetus and golden eagles, as the adult golden has a more solidly golden-brown coloration and all Haliaeetus eagles have obvious distinctive plumages as adults. Haliaeetus
eagles are often heavily streaked in their juvenile phase. Juvenile
golden eagles can have large patches of white on their wings and tail
that are quite different from the random, sometimes large and
splotchy-looking distribution of white typical of juvenile Haliaeetus.[15][55]
Distinguishing the golden eagle from other Aquila
eagles in Eurasia is more difficult. Identification may rely on the
golden eagle's relatively long tail and patterns of white or grey on the
wings and tail. Unlike golden eagles, other Aquila eagles do not
generally fly in a pronounced dihedral. At close range, the golden to
rufous nape-shawl of the golden eagle is distinctive from other Aquila. Most other Aquila eagles have darker plumage, although the smaller tawny eagle is often paler than the golden eagle (the overlap in range is verified only in Bale Mountains, Ethiopia). Among Eurasian Aquila, the adult eastern imperial and Spanish imperial eagle
come closest to reaching the size of golden eagles, but both are
distinguished by their longer necks, flatter wings in flight, white
markings on their shoulder forewing-coverts, paler
cream-straw coloured
nape patch and generally darker colouration. Juvenile imperial eagles
are much paler overall (caramel-cream in the Spanish; cream and tawny
streaks in the eastern) and are not likely to be confused.[15]Steppe eagles
can also approach golden eagles in size but are more compact and
smaller headed with little colour variation to their dark earth-brown
plumage, apart from juvenile birds which have distinctive cream-coloured
bands running through their coverts and secondaries.[5]Verreaux's eagles
are most similar in size and body shape to the golden, the body of the
Verreaux's eagle being slightly longer overall but marginally less heavy
and long-winged than the golden eagle's.[15]
The plumage is very distinctly different, however, as Verreaux's eagles
are almost entirely jet-black except for some striking, contrasting
white on the wing primaries, shoulders and upper-wing.[15] This closely related species is known to co-occur with the golden eagle only in the Bale Mountains of Ethiopia.[4]
Other booted eagles in the golden eagle's range are unlikely to be
confused due to differences in size and form. The only species in the
genus Aquila that exceeds the golden eagle in average wingspan and length is the wedge-tailed eagle of Australasia; however, the wedge-tailed eagle is a slightly less heavy bird.[21]
Golden eagles are fairly adaptable in habitat but often reside in
areas with a few shared ecological characteristics. They are best suited
to hunting in open or semi-open areas and search them out year-around.
Native vegetation seems to be attractive to them and they typically
avoid developed areas of any type from urban to agricultural as well as
heavily forested regions. In desolate areas (e.g., the southern
The biomes occupied by golden eagles are roughly concurrent with those of Eurasia. In western and northern Alaska and northern Canada to the Ungava Peninsula in Quebec,
the eagles occupy the Arctic fringe of North America (the species does
not range into the true high Arctic tundra), where open canopy gives way
to dwarf-shrub heathland with cottongrass and tussock tundra. In land-locked areas of the sub-Arctic, golden eagles are by far the largest raptor. From the Alaska Range to Washington and Oregon, it is often found in high mountains above the tree line or on bluffs and cliffs along river valleys below the tree line.[60][61]
In Washington state, golden eagles can be found in clear-cut sections
of otherwise dense coniferous forest zones with relatively little annual
precipitation.[62]
From east of the Canadian Rocky
Mountains to the mountains of Labrador,
the golden eagle is found in small numbers in boreal forest peatlands and similar mixed woodland areas. In the foothills of the Rocky Mountains in the United States are plains and prairies
where golden eagles are widespread, especially where there is a low
human presence. Here, grassland on low rolling hills and flat plains are
typical, interrupted only by cottonwood stands around river valleys and wetlands where the eagles may build their nests. Golden eagles also occupy the desert-like Great Basin from southern Idaho to northern Arizona and New Mexico. In this habitat, trees are generally absent other than junipers with vegetation being dominated by sagebrush (Artemisia)
and other low shrub species. Although the vegetation varies a bit more,
similar habitat is occupied by golden eagles in Mexico.[63][64][65] However, golden eagles are typically absent in North America from true deserts, like the Sonora Desert, where annual precipitation is less than 20 cm (7.9 in).[66] Golden eagles occupy the mountains and coastal areas of California and Baja California in Mexico where hot, dry summers and moist winters are typical. The golden eagles here often nest in chaparral and oak woodland, oak savanna and grassland amongst low rolling hill typified by diverse vegetation.[67] In the Eastern United States, the species once bred widely in the Appalachian Plateau near burns, open marshes, meadows, bogs and lakes.[68][69] In Eastern North America, the species still breeds on the Gaspe Peninsula, Quebec. Until 1999, a pair of golden eagles were still known to nest in Maine but they are now believed to be absent as a breeding bird from the Eastern United States.[4]
The golden eagles who breed in eastern Canada winter on montane grass
and heath fields in the Appalachian Plateau region, especially in Pennsylvania, New York, West Virginia, Maryland and Virginia. Most sightings in the Eastern United States recently are concentrated within or along southwestern border of the Appalachian Plateau (30% of records) and within the Coastal Plain physiographic region (33% of records).[70]
Though they do regularly nest in the marsh-like peatland
of the boreal forest, golden eagles are not generally associated with
wetlands and, in fact, they can be found near some of the most arid
spots on earth. In the wintering population of Eastern United States,
however, they are often associated with steep river valleys, reservoirs,
and marshes in inland areas as well as estuarine marshlands, barrier
islands, managed wetlands, sounds, and mouths of major river systems in
coastal areas. These wetlands are attractive due to a dominance of open
vegetation, large concentrations of prey, and the general absence of
human disturbance.[70] In the midwestern United States, they are not uncommon during winter near reservoirs and wildlife refuges that provide foraging opportunities at waterfowl concentrations.[71]
Golden eagles usually hunt during daylight hours, but were recorded hunting from one hour before sunrise to one hour after sunset during the breeding season in southwestern Idaho.[72]
The hunting success rate of golden eagles was calculated in Idaho,
showing that, out of 115 hunting attempts, 20% were successful in
procuring prey.[73]
A fully-grown golden eagle requires about 230 to 250 g (8.1 to 8.8 oz)
of food per day but in the life of most eagles there are cycles of feast
and famine, and eagles have been known to go without food for up to a
week and then gorge on up to 900 g (2.0 lb) at one sitting.[5]
Despite the dramatic ways in which they attain food and interact with
raptors of their own and other species, the daily life of golden eagles
is often rather uneventful. In Idaho,
adult male golden eagles were observed to sit awake on a perch for an
average of 78% of daylight, whereas adult females sat on nest or perched
for an average of 85% of the day.[76] During the peak of summer in Utah,
hunting and territorial flights occurred mostly between 9:00 and 11:00
am and 4:00 and 6:00 pm, with the remaining 15 or so hours of daylight
spent perching or resting.[17] When conditions are heavily anticyclonic, there is less
soaring during the day.[4] During winter in Scotland, golden eagles soar frequently in order to scan the environment for carrion.[4]
In the more wooded environments of Norway during autumn and winter,
much less aerial activity is reported, since the eagles tend to avoid
detection by actively contour-hunting rather than looking for carrion.[77]
Golden eagles are believed to sleep through much of the night. Although
usually highly solitary outside of the bond between breeding pairs,
exceptionally cold weather in winter may cause eagles to put their usual
guard down and perch together. The largest known congregation of golden
eagles was observed on an extremely cold winter's night in eastern
Idaho when 124 individuals were observed perched closely along a line of
85 power poles.[78]
Most populations of golden eagles are sedentary, but the species is actually a partial migrant.
Golden eagles are very hardy species, being well adapted to cold
climates, however they cannot abide declining available food sources in
the northern stretches of their range. Eagles raised at latitudes
greater than 60° N are usually migratory, though a short migration may
be untaken by those who breed or hatch at about 50° N.[79] During migration, they often use soaring-gliding flight, rather than powered flight.[79] In Finland,
most banded juveniles move between 1,000 and 2,000 km (620 and
1,240 mi) due south, whereas adults stay locally through winter. Further
east, conditions are too harsh for even wintering territorial adults.[4] Golden eagles that breed from the Kola peninsula to Anadyr in the Russian Far East migrate south to winter on the Russian and Mongolian steppes, and the North China Plains. The flat, relatively open landscapes in these regions hold relatively few resident breeding golden eagles.[80] Similarly the entire population of golden eagles from northern and central Alaska and northern Canada migrates south. At Mount Lorette in Alberta, approximately 4,000 golden eagles may pass during the fall, the largest recorded migration of golden eagles on earth.[81]
Here the mountain ranges are relatively moderate and consistent, thus
being reliable for thermals and updrafts which made long-distance
migrating feasible.[81] Birds hatched in Denali National Park in Alaska traveled from 818 to 4,815 km (508 to 2,992 mi) to their winter ranges in western North America.[79] These western migrants may winter anywhere from southern Alberta and Montana to New Mexico and Arizona and from inland California to Nebraska. Adults who bred in northeastern Hudson Bay area of Canada reached their wintering grounds, which range from central Michigan to southern Pennsylvania to northeastern Alabama, in 26 to 40 days, with arrival dates from November to early December.[82]
The departure dates from wintering grounds are variable. In
southwestern Canada, they leave their wintering grounds by 6 April to 8
May (the mean being 21 April); in southwestern Idaho, wintering birds
leave from 20 March to 13 April (mean of 29 March); and in the Southwestern United States, wintering birds may depart by early March.[4][79][83]
Elsewhere in the species' breeding range, golden eagles (i.e., those
who breed in the contiguous Western United States, all of Europe but for
Northern Scandinavia, North Africa and all of Asia but for Northern
Russia) are non-migratory and tend to remain within striking distance of
their breeding territories throughout the year.[15]
In Scotland, among all recovered, banded golden eagles (36 out of 1000,
the rest mostly died or disappeared) the average distance between
ringing and recovery was 44 km (27 mi), averaging 63 km (39 mi) in
juveniles and 36 km (22 mi) in older birds.[4] In the dry Southwestern United States, golden eagles tend to move to higher elevations once the breeding season is complete.[53] In North Africa,
populations breeding at lower latitudes, like Morocco, are mostly
sedentary, although some occasionally disperse after breeding to areas
outside of the normal breeding range.[84]
Territoriality is believed to be the primary cause of interactions
and confrontations between non-paired golden eagles. Golden eagles
maintain some of the largest known home ranges (or territories) of any
bird species but there is much variation of home range size across the
range, possibly dictated by food abundance and habitat preference. Home
ranges in most of the range can vary from 20 to 200 km2 (7.7 to 77.2 sq mi).[85] In San Diego County in California, the home ranges varied from 49 to 137 km2 (19 to 53 sq mi), with an average of 93 km2 (36 sq mi).[86]
However, some home ranges have been much smaller, such as in
southwestern Idaho where, possibly due to an abundance of jackrabbits,
home ranges as small as 4.85 km2 (1.87 sq mi) are maintained.[64]
The smallest known home ranges on record for golden eagles are in the
Bale Mountains of Ethiopia, where they range from 1.5 to 9 km2 (0.58 to 3.47 sq mi).[87]
46% of undulating displays in Montana occurred shortly after the
juvenile eagles left their
parents range, suggesting that some residents
defend and maintain territories year-round.[88] Elsewhere it is stated that home ranges are less strictly maintained during winter but hunting grounds are basically exclusive.[4]
In Israel and Scotland, aggressive encounters peaked from winter until
just before egg-laying and were less common during the nesting season.[4][89] Threat displays include undulating flight and
aggressive direct flapping flight with exaggerated downstrokes.[49]
Most displays by mature golden eagles (67% for males and 76% for
females) occur, rather than around the nest, at the edge of their home
ranges.[76] In Western Norway, most recorded undulating flight displays occur during the pre-laying period in late winter/early spring.[77] Display flights seem to be triggered by the presence of other golden eagles.[4] The use of display flights has a clear benefit in that it lessens the need for physical confrontations, which can be fatal.[76]
Usually, non-breeding birds are treated aggressively by the golden
eagle maintaining their home range, normally being chased to the
apparent limit of the range but with no
actual physical contact.[4]
The territorial flight of the adult golden eagle is sometimes preceded
or followed by intense bouts of undulating displays. The invader often
responds by rolling over and presenting talons to the aggressor. Rarely,
the two eagles will lock talons and tumble through the air; sometimes
fall several revolutions and in some cases even tumble to the ground
before releasing their grip.[77][90]
In some parts of the Alps, the golden eagle population has reached the
saturation point in appropriate habitat and apparently violent
confrontations are more common than in other parts of the
range.[91]
Golden eagles may express their aggression via body language while
perched, typically the adult female when confronted by an intruding
eagle: the head and body are upright, feathers on head and neck are
erect; the wings may be slightly spread and beak open; often accompanied
by intense gaze. They then often engage in a similar posture with wings
spread wide and oriented toward the threat; sometimes rocking back on
tail and even flopping over onto the back with talons extended upward as
defense. Such behavior may be accompanied by wing slap against the
threatening intruder.[49]
When approached by an intruder, the defending eagle turns away,
partially spreads tail, lowers head, and remains still; adults on the
nest may lower head and "freeze" when approached by a person or a
helicopter.[49]
Females in Israel displayed more than males and mostly against
interspecific intruders; males apparently displayed primarily as part of
courtship.[89]
Five of 7 aggressive encounters at carcasses during winter in Norway
were won by females; in 15 of 21 conflicts, the younger bird dominated
an older conspecific.[92]
However, obvious juvenile eagles (apparent to the adult eagles due to
the amount of white on their wings and tail) are sometimes allowed to
penetrate deeply into a pair's home range and all parties commonly
ignore each other.[93][94] In North Dakota,
it was verified that parent eagles were not aggressive towards their
own young after the nesting period and some juveniles stayed on their
parents territory until their 2nd spring and then left by their own
accord.[95]
Golden eagles usually mate for life. A breeding pair is formed in a
courtship display. This courtship includes undulating displays by both
in the pair, with the male bird picking up a piece of rock or a small
stick, and dropping it only to enter into a steep dive and catch it in
mid-air, repeating the maneuver 3 or more times. The female takes a
clump of earth and drops and catches it in the same fashion.[4][27] Golden eagles typically build several eyries
within their territory (preferring cliffs) and use them alternately for
several years. Their nesting areas are characterized by the extreme
regularity of the nest spacing.[96]
Mating and egg-laying timing for golden eagle is variable depending on
the locality. Copulation normally lasts 10–20 seconds. Mating seems to
occur around 40–46 days before the initial egg-laying.[4]
The golden eagle chick may be heard from within the egg 15 hours before
it begins hatching. After the first chip is broken off of the egg,
there is no activity for around 27 hours. Hatching activity accelerates
and the shell is broken apart in 35 hours. The chick is completely free
in 37 hours.[49]
In the first 10 days, chicks mainly lie down on the nest substrate.[49] They are capable of preening on their second day but their parents keep them warm until around 20 days.[4] They grow considerably, weighing around 500 g (1.1 lb).[97] They also start sitting up more.[49]
Around 20 days of age, the chicks generally start standing, which
becomes the main position over the course of the next 40 days.[49] The whitish down continues until around 25 days of age, at which point it is gradually replaced by dark contour feathers that eclipse the down and the birds attain a general piebald appearance.[4]
After hatching, 80% of food items and 90% of food biomass is captured
and brought to the nest by the adult male. Fledging occurs at 66 to 75
days of age in Idaho and 70 to 81 days in Scotland. The first attempted
flight departure after fledging can be abrupt, with the young jumping
off and using a series of short, stiff wing-beats to glide downward or
being blown out of nest while wing-flapping. 18 to 20 days after first
fledging, the young eagles will take their first circling flight, but
they cannot gain height as efficiently as their parents until
approximately 60 days after fledging. In Cumbria,
young golden eagles were first seen hunting large prey 59 days after
fledging. 75 to 85 days after fledging, the young were largely
independent of parents. Generally, breeding success seems to be greatest
where prey is available in abundance.[4]
Golden eagles are fairly long-living birds in natural conditions if
they survive their first few years. The survival rate of raptorial birds
tends to increase with larger body size, with a 30–50% annual loss of
population rate in small falcons/accipiters, a 15–25% loss of population
rate in medium-sized hawks (e.g.,
Natural sources of mortality are largely reported in anecdotes. On
rare occasions, golden eagles have been killed by competing predators or
by hunting mammalian carnivores, including the aforementioned
wolverine, snow leopard, cougar, brown bear and white-tailed eagle
attacks. Most competitive attacks resulting in death probably occur at
the talons of other golden eagles. Nestlings and fledglings are more
likely to be killed by another predator than free-flying juveniles and
adults. It has been suspected that golden eagle nests may be predated
more frequently by other predators (especially birds, which are often
the only other large animals that can access a golden eagle nest without
the assistance of man-made climbing equipment) in areas where golden
eagles are regularly disturbed at the nest by humans. Jeff Watson
believed that common raven occasionally eats golden eagle eggs but only
in situations where the parent eagles have abandoned their nesting
attempt.
predation by other bird species on golden eagle nests.[4]
Occasionally, golden eagles may be killed by their prey in
self-defense. There is an account of a golden eagle dying from the
quills of a North American porcupine (Erethizon dorsatum) it had attempted to hunt.[104] On the Isle of Rùm
in Scotland, there are a few cases of red deer trampling golden eagles
to death, probably the result of a doe having intercepted a bird that
was trying to kill a fawn.[105]
Although usually well out-matched by the predator, occasionally other
large birds can put up a formidable fight against a golden eagle. An
attempted capture of a great blue heron by a golden eagle resulted in the death of both birds from wounds sustained in the ensuing fight.[106] There is at least one case in Scotland of a golden eagle dying after being "oiled" by a northern fulmar,
a bird whose primary defense against predators is to disgorge an oily
secretion which may inhibit the predator's ability to fly.[107]
Of natural sources of death, starvation is probably under-reported. 11
of 16 dead juvenile eagles which had hatched in Denali National Park
had died of starvation.[102]
Of 36 deaths of golden eagles in Idaho, 55% were possibly attributable
to natural causes, specifically 8 (26%) from unknown trauma, 3 (10%)
from disease and 6 (19%) from unknown causes.[108]
Of 266 golden eagle deaths in Spain, only 6% were from unknown causes
that could not be directly attributed to human activities.[109] Avian cholera caused by bacteria (Pasteurella multocida) infects eagles that eat waterfowl that have died from the disease. The protozoanTrichomonas sp. caused the deaths of four fledglings in a study of wild golden eagles in Idaho.[110] Several further diseases that contribute to golden eagle deaths have been examined in Japan.[111] A captive eagle died from two malignant tumors – one in the liver and one in the kidney.[112]
In December 2016, the US Fish and Wildlife Service
proposed allowing wind-turbine electric generation companies to kill
golden eagles without penalty, so long as "companies take steps to
minimize the losses". If issued, the permits would last 30 years, six
times the current 5-year permits.[113][114]
Human beings have been fascinated by the golden eagle as early as the
beginning of recorded history. Most early-recorded cultures regarded
the golden eagle with reverence. In pre-Hispanic
It was only after the Industrial Revolution,
when sport-hunting became widespread and commercial stock farming
became internationally common, that humans started to widely regard
golden eagles as a threat to their livelihoods. This period also brought
about the firearm and industrialized poisons, which made it easy for
humans to kill the evasive and powerful birds.
In 2017 the French Army trained golden eagles to catch drones.[116] The golden eagle is officially Utah's state bird of prey.[citation needed]
At one time, the golden eagle lived in a great majority of temperate Europe, North Asia, North America, North Africa, and Japan.
Although widespread and quite secure in some areas, in many parts of
the range golden eagles have experienced sharp population declines and
have even been extirpated from some areas. The number of golden eagles
from around the range is estimated to be between 170,000 and 250,000
while the estimates of breeding pairs are from 60,000 to 100,000.[4][117]
It has the largest known range of any member of its family, with a
range estimated at 140 million square kilometers. If its taxonomic order is considered, it is the second most wide-ranging species after only the osprey (Pandion haliaetus).[2][118]
Few other eagle species are as numerous, though some species like the
tawny eagle, wedge-tailed eagle and bald eagle have total estimated
populations of a similar size to the golden eagle's despite their more
restricted distributions.[5][15] The world's most populous eagle may be the African fish eagle (Haliaeetus vocifer), which has a stable total population estimated at 300,000 and is found solely in Africa.[5][119] On a global scale, the golden eagle is not considered threatened by the IUCN.[2]