The tawny eagle (Aquila rapax ) is a large bird of prey. Like all eagles, it belongs to the family Accipitridae. Its heavily feathered legs illustrate it to be a member of the subfamily Aquilinae, also known as "booted eagles". Tawny eagles have an extensive but discontinuous breeding range that constitutes much of the African continent as well as the Indian subcontinent, with rare residency occurring in the southern Middle East. Throughout its range, it favours open dry habitats such as semideserts, deserts steppes, or savanna plains. Despite its preference for areas of aridity, the species seldom occurs in areas where trees are entirely absent. It is a resident breeder which lays one to three eggs in a stick nest mostly commonly in the crown of a tree. The tawny eagle is perhaps the most highly opportunistic of all of its taxonomic clan, and often scavenges on carrion or engages in kleptoparasitism towards other carnivorous animals but is also a bold and active predator, often of relatively large and diverse prey. It is estimated that tawny eagles can reach the age of 16 years old. Nonetheless, precipitous declines have been detected throughout the tawny eagle's range. Numerous factors, particularly loss of nesting habitat due to logging and global warming, as well as persecution (largely via poisoning) and other anthropogenic mortality (largely through contact with various manmade objects) are driving the once numerous tawny eagle perhaps to the brink of extinction.
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DiurnalDiurnal animals are active during the daytime, with a period of sleeping or other inactivity at night. The timing of activity by an animal depends ...
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CarnivoreA carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of a...
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ScavengerScavengers are animals that consume dead organisms that have died from causes other than predation or have been killed by other predators. While sc...
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ArborealArboreal locomotion is the locomotion of animals in trees. In habitats in which trees are present, animals have evolved to move in them. Some anima...
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TerrestrialTerrestrial animals are animals that live predominantly or entirely on land (e.g., cats, ants, snails), as compared with aquatic animals, which liv...
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TerritorialA territory is a sociographical area that which an animal consistently defends against the conspecific competition (or, occasionally, against anima...
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CongregatoryCongregatory animals tend to gather in large numbers in specific areas as breeding colonies, for feeding, or for resting.
Oviparous animals are female animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive...
Altricial animals are those species whose newly hatched or born young are relatively immobile. They lack hair or down, are not able to obtain food ...
Soaring birds can maintain flight without wing flapping, using rising air currents. Many gliding birds are able to "lock" their extended wings by m...
Gliding flight is heavier-than-air flight without the use of thrust and is employed by gliding animals. Birds in particular use gliding flight to m...
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MonogamyMonogamy is a form of relationship in which both the male and the female has only one partner. This pair may cohabitate in an area or territory for...
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Not a migrantAnimals that do not make seasonal movements and stay in their native home ranges all year round are called not migrants or residents.
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starts withThe tawny eagle is considered to appear "inelegant, scruffy-looking" but has a fairly characteristic aquiline silhouette. The species has a fairly long neck and long deep bill with a gape line level with the eye, moderately long wings with fairly pronounced "fingers" and a slightly rounded to almost square-ended and shortish tail, which can be more reminiscent of the tail of a vulture than that of other eagles. The feathering on the legs is extensive and can appear almost baggy-looking. The bill and head are strong and bold, the body well-proportioned and feet are powerful while the countenance is quite fierce-looking. While perching, the tawny eagle tends to sit rather upright, often on stumps, posts, low trees or treetops for long periods of the day or may descend to the ground to walk somewhat unsteadily with a more horizontal posture. The wingtips when perched are roughly even with the tip of the tail. Adults have variably colored eyes, ranging from yellow to pale brown to yellow brown, while those of juveniles are dark brown. Both the cere and feet are yellow at all ages. The tawny eagle is polymorphic with considerable individual variation in plumage, resulting in occasional disparities in plumages that can engender confusion in some. In adulthood, they can vary in coloration from all dark grey-brown to an occasionally streaky (or more plain) foxy-rufous to buffish-yellow. Most adults are usually a general grey-brown or rufous-tawny color, with occasional pale spotting visible at close quarters on the nape and belly, coverts uniformly toned as the body. The nape is consistently dark and uniform despite the feathers often being tipped paler with other feathers in adults, lacking the contrasting paler feathers often seen in other Aquila. Females, in addition to being slightly larger, may tend to be slightly darker and more streaked than the males. The most blackish-brown individuals tend to occur in India. Adults often show relatively little varying colors apart from their somewhat blacker wing and tail feathers, though when freshly molted great wing coverts and secondaries may show small pale tips which may form pale lines along closed wing has tawny upper parts and blackish flight feathers and tail. The head is often similarly tawny in colour as the body but may also sometimes shows darker eyebrows, other thin brown streaks or a darker chin. Meanwhile, the tail is plain or obscurely dark barred (with around 7 subtle bands). The dark morph adult is essentially all dark, dull brown. Some dark morph tawny eagles with wear may show irregular streaking or molting browns and more blackish feathers. Intermediate morph are dark to rufous brown above with the mantle and wing coverts variably streaked or molted lighter rufous as is the head with the crown or crown-sides being paler. The intermediate morph's underside is largely rufous (especially farther south in Africa) with breast and flanks very heavily and broadly streaked dark brown, though at times appears all dark brown contrasting with plain trousers and crissum. Pale morph adult tawny eagles always show a clear contrast between the pale body and wing coverts which bear darker flight feathers and tail. In pale morphs, the underparts are rufous buff to lighty tawny-brown, phasing into somewhat darker lesser and median wing coverts to darker brown to even blackish greater coverts and flight feathers. The head may too be tawny in pale morph tawny eagles but sometimes with thin brown streaks or darker chin. Below pale morph adults are all light rufous to tawny buff or brown, sometimes paler below the belly area. In worn individuals the bodily feathers of pale morph tawny eagles can appear almost whitish. Dark morph juvenile tawny eagles are generally light rufous to rufous brown with creamier lower back to upper tail coverts. Juveniles show thinly pale-tipped dark brown greater coverts and remiges while the tail is barred grey and brown usually with a narrow creamy tip. Dark morph juveniles may fade to pale buff or creamy often before molting into browner plumage. Subsequent stages are not as well-known but it appears dark morph subadults gradually manifest a darker brown or rufous brown color on the mantle, as well as on the head and upper breast while maintaining a buffish rear body (i.e. lower back and rump patch). Generally other morphs are similar but not as well-known and are perhaps individually inconsistent. Many are rufous or sandy after a molt but have mottling later on, the extent of pale feathers indicative perhaps of their ultimate adult morph.
In flight, the tawny eagle appears as a large raptor with a noticeably protruding head on a long neck, with a deep chest, long and broad wings with a somewhat narrower seven-fingered hand. The trailing edge of the wing is slightly curved outwards, indenting at the junction of primaries and secondaries, whilst the rounded, medium-length tail is usually held spread. The deep beats of the kinked wings can make their flight appear rather heavy and slow but they are quicker and more expansive in wing movements and often less forceful-looking than larger Aquila like steppe eagles and can be very agile when chasing other raptors to rob them. Tawny eagles soar with flat wings or very slightly raised and hands only slightly lower, and may fly similarly in a glide but may too arch when in a fast glide. Adult dark morphs are more or less uniform dark brown above and below, showing indistinctly and slightly paler and greyish primaries on both sides. Above, the main contrast on dark morphs above is paler creamy rump patch while, on the underside, the greyish color is contrasted with blackish tips and a diffused trailing edge along both the wings and tail. Intermediate morph tawny eagles are variably rufous streaked on brown to rufous brown on the back and wing coverts with a similar contrasting pale rump above as dark morphs. Below the intermediate's heavy dark streaks are only subtly different and their coloring can appear almost uniform. The wing quills of intermediate morphs are often greyer with a stronger contrast of the paler inner primaries and blackish wing ends. Pale morph are all pale tawny or buffish on both sides of the wing, which contrasting strongly with demarcated dark brown about the greater coverts, flight feathers and tail and usually the scapulars. The primaries are quite pale on pale morphs with sometimes the hint of a pale carpal comma. Some pale adults have pale bases to all the underprimaries and the quills are sometimes unbarred, but more usually the feathers have dense but narrow dark bars. Dark morph juveniles are light rufous to pale tawny body above which contrasts strongly with dark brown greater coverts, rear scapulars, flight feathers and tail, in turn all highlighting the creamy lower back to tail coverts. Below dark morph juveniles can look similar to pale morph adults apart from trailing whitish edges and often irregular pale diagonals along tips of greater wing coverts, though usually these fade early on. Little is known plumage development but the young eagles moult into brown, becoming patchy with intermediate often showing 1-3 darker bars on wing linings. The underparts of subadults (i.e. around 2 to 3 years or old) are typically two-toned, with darker brown about the breasts, belly and underwings coverts while the remainder of the underbody is creamy light in colour. This two-toned pattern is evidenced in subadult tawny eagles both from India and Africa. Adult plumage is obtained between the 4th and 5th years of life.
This is a large bird of prey, though is medium-sized for an eagle and it is one of the smaller species in the genus Aquila. Among currently accepted species in the genus, it is of quite similar size to Bonelli's eagles (Aquila fasciata ) (though is notably longer winged), slightly larger than African hawk-eagles (Aquila spilogaster ) and much larger than Cassin's hawk-eagles (Aquila africanus ). Otherwise, females of the larger species of Aquila are frequently around twice as heavy as an average tawny eagle. As is typical in birds of prey, the female tawny eagle is larger than the male, though relatively modestly so and a difference between the sexes is typically up to 15%. In total length, tawny eagles can measure from 58 to 75 cm (23 to 30 in). A typical length for a tawny eagle is considered about 65 cm (26 in). Wingspans can measure from 157 to 190 cm (5 ft 2 in to 6 ft 3 in). Weight can range in fully grown birds from 1.5 to 3.1 kg (3.3 to 6.8 lb). Average weights were reported in one study as 1.91 kg (4.2 lb) in 5 males and 1.97 kg (4.3 lb) in 5 females. In another study, 10 unsexed adult tawny eagles were found to have weighed 2.5 kg (5.5 lb) on average while, for the same data pool, a sample of 15 had an average wingspan of 182.9 cm (6 ft 0 in). Another small sample of African males, sample size four, averaged 1.85 kg (4.1 lb) while three females averaged 2.28 kg (5.0 lb). The mean mass of the species in one estimate was 2.3 kg (5.1 lb). In all standard measurements combined, the wing chord can vary from 473 to 565 mm (18.6 to 22.2 in), the tail from 242 to 295 mm (9.5 to 11.6 in) and the tarsus from 79 to 92 mm (3.1 to 3.6 in). The culmen length of Kenyan tawny eagles was measured at 33.3 to 42.4 mm (1.31 to 1.67 in), averaging 37.7 mm (1.48 in), while the gape width is 44 mm (1.7 in) on average, ranging from 40.3 to 49.9 mm (1.59 to 1.96 in). The hallux-claw, the enlarged rear talon often used as a killing instrument on accipitrids, can measure from 27 to 37.7 mm (1.06 to 1.48 in), averaging 31.8 mm (1.25 in) in one sample and 32.3 mm (1.27 in) in another. The talon size is not especially large for a booted eagle and is proportionately similar in size to those of steppe eagles and eastern imperial eagles (Aquila heliaca ).
Tawny eagles have an extremely extensive natural distribution. The African population can be found in three, fairly discrete populations. One of these is found in North Africa in south-central Morocco, possibly northern Algeria, southwestern Mauritania, Senegambia, southern Mali, central and southern Niger eastward through southern Chad, northern and central Sudan to most of Ethiopia and Somalia (but for the northeast and central-east). The north African population is scarce. In Morocco, they are heavily depleted with a few populations left in some regions such as Tarfaya, Tan-Tan and Souss-Massa. They are likely extirpated from Tunisia, where they were once frequent. In West Africa, some tawny eagles occur in Gambia, Togo, Nigeria and (though possibly not breeding) in Ivory Coast and Ghana. In east Africa and central Africa, the tawny eagle is found in central and eastern Democratic Republic of the Congo and throughout the drier portions of Uganda and in the entire nations of Kenya, Tanzania, Zambia (quite often residing in the Luangwa valley and the Chambeshi drainage), Malawi and Mozambique. In east Africa, it is considered perhaps the most widely distributed and regularly sighted brown eagle. In southern Africa, the tawny eagle is found throughout Zimbabwe (now often rare apart from Matabeleland and Chipinga Uplands), Botswana (still regular in Okavango Delta) and some areas of Namibia, southern and western Angola (Cuando Cubango, Cunene, Huíla Namibe, to Malanje), Eswatini, Lesotho and northern and central parts of South Africa, i.e. mainly north of the Orange River but sometimes down to the Cape Province. The tawny eagle may be extinct as a breeder in Eswatini where it was last confirmed to have bred in 2001.
Out of Africa, the species may possibly be found in the southwestern part of the Arabian peninsula, i.e. in Yemen and extreme southwestern Saudi Arabia in the Tihamah and 'Asir Regions, but few to none confirmed breeding events have been reported in the last few decades. The tawny eagle is considered a rare vagrant in Israel, though some are verified, other reports of them often turn out to be misidentified steppe eagles. They are also known as a rare vagrant in Oman. In Asia, the tawny eagle exists in isolation in southeastern Iran (as in Arabia, verified recent breeding is not known) and somewhat more continuously in eastern Pakistan (often in the Indus valley), much of north and peninsular India, eastward scarcely through southern Nepal and Assam. Though Nepali tawny eagles are rarely recorded, it is thought that the species still resides there in lowland semi-deserts. The Indian range is from Punjab through the Indo-Gangetic Plain and western Bengal, northeastern Bihar, the Deccan Plateau with range continuing down to Andhra Pradesh, Karnataka and (mainly north-central) Tamil Nadu. Records of vagrating tawny eagles turning up in Myanmar, northern Vietnam and Thailand are thought to have been likely misidentified steppe eagles or are based on now unidentifiable specimens. A small handful of vagrants have been verified to turn up in Sri Lanka (the only known appearance by an Aquila eagle there). Old reports of vagrancy, probably in need of confirmation, are known also from Afghanistan.
Tawny eagles occurs in fairly open country at varied elevations but usually live in drier areas. In West Africa, the species breeds often in relatively moist forest-savanna mosaics but can move into dry woodlands and semi-deserts when not breeding. In Morocco, the species prefers forested areas near mountains with adjacent plains. Elsewhere in Africa, tawny eagles typically inhabit wooded savanna such as dry Acacia savanna and semi-desert to desert areas. However, extreme desert areas, completely lacking in arborescent growth, are avoided nearly as much so as humid tropical rainforests. It also occurs at times in manmade areas such as arable lands, roadsides, dams, farmland, cattle pastures and game areas if feeding opportunities occur in them. In southern Africa, thornveld is often the preferred habitat with the tawny eagles mostly preferring stands of Acacia. Despite similar climates, within the miombo woodland, the tawny eagle tends to be more scarce. In India, similar habitats may largely be used but the tawny eagle may fairly often occur too in the vicinity of villages and cultivations and frequents garbage dumps and slaughterhouses somewhat more so than they do in Africa. In addition to all gradients of arid zones, in India, the tawny eagle frequently is found around thorn forests. Tawny eagles may live from sea level to about 3,000 m (9,800 ft) but tends to prefer somewhat lower elevations. Despite a certain level of aridity expected in tawny eagle habitats, they normally will not nest unless a habitat meets certain demands. The tawny eagle's presence is predicated on the availability of ephemeral rainfall during the wet season. This reliance on some rainfall is probably key to habitat quality and resulting prey populations to some extent, but also to the availability of nesting sites. The tawny eagle is by and large an obligate tree nester and so areas that become too arid to support tree growth or where trees are overharvested are unlikely to retain the species.
The tawny eagle, quite unlike the steppe eagle, is largely sedentary and non-migratory. However, in Africa it is at times considered to be fairly nomadic and can engage in some seasonal movements. In west Africa, A. r. belisarius rather regularly travels shorter distance to damp woodlands during October through November, returning north in April, and perhaps at least at times, migrates into Kalahari region of Botswana and may vagrate to southern South Africa. Sometimes, tawny eagles seem to ping semi-regularly between Ethiopia and west Africa. Some long distance wandering has even been reported, such as a vagrant A. r. belisarius in Tunisia and as far as Egypt (where twice recorded in the 1950s) and even Israel (3 winter records in the 1990s) and Oman. From the Indian range, individuals vagrate not infrequently to nearby Bangladesh, most likely as juveniles post-dispersal wanderings, but reports of the species wandering into southeast Asia such as Thailand are now considered likely apocryphal. Generally, in areas such as southern Africa, tawny eagles usually seldom seem to leave their established breeding territories and juvenile eagles generally wander no more than several dozen kilometres from their original nest. A bird banded as a nestling in Esigodini was recovered quite nearby at Fort Rixon more than two years later. However, in a rather far dispersal for southern Africa, one eagle banded as a nestling was recovered 330 km (210 mi) away from its nest of origin in Zimbabwe four years later. Inconsistent and seemingly unpredictable movements by tawny eagles have been proven via experimental ecological studies to be actually be instances of eagles searching out new areas to compensate for lack of rainfall. While non-breeding steppe eagles are often slightly social and flock at opportunistic feeding sources, the tawny eagle is usually considered solitary. However, groups of two to three tawny eagles are sometimes seen, such as in the Indian subcontinent, but occasionally group sizes may even exceed this figure. In the Mirpur Division of Azad Kashmir in Pakistan, small flocks of tawny eagles have reportedly been witnessed gathering in warmer spots between November and February, over three years of study. Small groups or aggregations are known to occur in Africa as well near concentrated foods and even communal roost have been reported in trees, power pylons or on the ground. Like many large raptors, the tawny eagle probably spends the majority of its day perched but take wing a few times a day. Unlike most large eagles, in India at least, tawny eagles are often fairly accustomed to humans and may allow fairly close approach by observers.
The tawny eagle is unique as an Aquila eagle in the lack of apparent specialization in its feeding behaviour. While most other Aquila will opportunistically scavenge, the tawny eagle freely takes to scavenging on carrion, perhaps doing so at all times of the year, though do so somewhat more so when not breeding. Routine scavenging often drives tawny eagles to refuse dumps in or near villages and slaughterhouses, particularly in India, and to associate quite often with vultures at carrion sites. They are also frequently recorded on roadsides where roadkill provides a steady food source. More routinely than almost any other raptor, perhaps, it is a very skilled pirate, regularly engaging in kleptoparasitism of other birds of prey. However, descriptions of the tawny eagle as "sluggish", "not very distinguished" and "unimpressive" are not particularly apt as the tawny eagle is a highly rapacious predator that attacks very variable ranges of live prey including particularly large prey. This species hunts mainly by a short dive or pounce from a perch or by stoop from up high in a soaring flight. In the Indian subcontinent, preferred hunting perch trees were Vachellia nilotica, Prosopis cineraria and Capparis decidua. It may also often forage by walking on the ground. Mostly, tawny eagles target live prey that is on the ground, seldom targeting arboreal prey. However, they will sometimes fly down and take birds on the wing. Avian prey known to be killed in the air has ranged from speckled pigeons (Columba guinea ) to flamingoes. Tawny eagles may hunt frequently in pairs during the breeding season, often securing larger prey than is does in the non-breeding season. Sometimes this tandem hunting by pairs can occur in any season. It is likely that tandem hunting by pairs involves one bird engaging in conspicuous flight to distract the quarry while another flies inconspicuously to sneak up on and kill the prey, as has been reported in other tandem hunting raptors. Nocturnal animals such as genets and springhares have been preyed upon by tawny eagles in areas where there was no possibility they were killed by traffic at night. In addition to other observations have been made where tawny eagles drink and bath at night, some nocturnal subsistence behaviour by this species has been inferred but no irrefutable evidence has been brought forth either. Semi-regular attendance at grassfires in India, presumably in order to capture displaced creatures, has been reported. More than 200 species, including both live prey and carrion, are known to be eaten by tawny eagles and they may have one of the most variable diet of all tropical eagles. Reportedly, most prey the tawny eagle will take alive will weigh not less than 125 g (4.4 oz) and not more than 2.5 kg (5.5 lb), however live prey has been revealed to be regularly more variable than even that estimate represents. One compilation study showed that, compared to 8 other Aquila and spotted eagles, the tawny eagle's diet was the most evenly spread across all weight classes of prey from under 63 g (2.2 oz) to over 4 kg (8.8 lb), though took prey in the latter prey class slightly less so than the much larger golden and wedge-tailed eagles (Aquila audax ). This study further determine that the most often focused on weight class in tawny eagle's diets were 0.5 to 1 kg (1.1 to 2.2 lb) and 1 to 2 kg (2.2 to 4.4 lb) prey class, accounting for a little less than half of the prey by quantity. According to this authority, the mean prey size falls around approximately 921 g (2.030 lb), which is around 5 times greater than the mean estimated prey size for the steppe eagle species, around 38% greater than mean estimated prey size of imperial eagles and considerably less only than the golden, wedge-tailed and Verreaux's eagles among the 8 studied Aquila and Clanga species.
The tawny eagle often seems to pair for life. Like most birds of prey, they are quite territorial towards conspecifics. The commonest display is single or mutual high circling or soaring often in wide spiral. Males will sometimes dive and stoop repeatedly around the female, though she does not usually respond by turning over. Pairs may engage in the display each to strengthen pair bonds. Occasionally two tawny eagles will interlocks talons to descend rapidly, cartwheeling down 30 m or more within a few seconds, sometimes disengaging just before the ground. In other related eagles of the Aquilinae subfamily, cartwheeling interactions are usually considered to be aggressive fights between a territorial eagle and an intruder of the same gender. Prior studies thought this to be the case for the tawny eagle, with an estimated 82% of cartwheeling instances thought to be aggressive, 11% for courtship and 7% for apparent play. However, through closer observations evidence has been made of frequent cartwheeling between males and females as a regular part of the courtship display. Undulating sky dances are sometimes performed too by males with a series of descents and upward swoops on partially close wings, accompanied by calling. However, instances of this seem to be rare. In one instance, two males appeared to engage in a display for a single female. Per one author's opinion the aerial displays of the tawny eagle are "not particularly spectacular compared to other eagles". The breeding season tends to fall in March to August in northeastern Africa, October to June in west Africa and in almost all months of the year but in central, east and southern Africa, but mainly from May to November in Kenya and April to January in central and southern Africa. In India, the breeding season is usually November to May, but occasionally can vary from any time from October to August. Mating generally occurs in and around the nest vicinity. The density very variable on the African continent overall of breeding pair which were estimated to occupy about 75 to 300 km2 (29 to 116 sq mi) each. Zimbabwe nest spacing was found to be 7 to 10 km (4.3 to 6.2 mi) in one study. On the border of Kruger National Park, 7 pairs found in a 460 km2 (180 sq mi) area but in regular spaced pylon nests in western Transvaal, nests were 19 to 20 km (12 to 12 mi) apart. In Hwange National Park, over 11 years of study, 92 pairs on were found to be nesting over basalt in a 4,724 km2 (1,824 sq mi) area while 84 pairs on Kalahari sands in a 9,876 km2 (3,813 sq mi) area. Mean nest distances on basalt were around 4 km (2.5 mi) while on sands it was around 59 km (37 mi). In Zambia, the nesting density was considered high for the species at a pair per 28 km2 (11 sq mi).
The nests of the tawny eagle are large platforms, composed of sticks but sometimes incorporating animal bones. Nesting sites tend to be open to the sky, in flat, open or hilly country, and offer a commanding a good view of the surrounding country. The sites are not infrequently close to watering holes and, more so in India, close to villages. Nests are usually 6 to 15 m (20 to 49 ft) above the ground, though seldom can be up to 30 m (98 ft) high. Nests are located at the top crown of the tree and only very rarely are placed beneath the canopy or on a lateral branch. In Kenya, tawny eagles showed no nesting preference according to tree height or spatial distribution of trees; however, they preferred Euphorbia, Boscia and Euclea tree species. In India, commonly used trees used in the northern areas are Ficus religiosa, Dalbergia sissoo and mango trees while in the arid Kutch and western Rajasthan areas they often nest in rather stunted Vachellia nilotica and Prosopis chilensis (i.e. usually the nests here are 4 to 6 m (13 to 20 ft) high but are sometimes down to 4 m (13 ft) ). Trees are usually selected that have prickly branches, presumably for protection. Despite their prominent position in the trees, the nests can be surprisingly hard to perceive peering from the ground level. In Kgalagadi Transfrontier Park, South Africa, tawny eagles build nests that are positioned in the canopy of large Vachellia erioloba trees. These Kgalagadi pairs tend to be the largest and tallest trees, averaging at 10.9 m (36 ft). Tawny eagles in India reportedly often nest in a tree over successive years, but the species is threatened by the lopping and cutting of all remaining suitable trees for fuel and fodder. Tawny eagles in Kgalagadi Transfrontier Park, on the other hand, build new nests yearly and only 2% of nests are reused for breeding purposes the following year. Potential risk of collapse and growth of branches around the nest are thought to be factors limiting nest reuses in Africa. Usually new nests are not more than 2 km (1.2 mi) away from the prior nest. Both sexes participate in nest building and the repair of a nest takes up to 4 to 7 weeks, though most of the construction can be completed within about a week. For an eagle, their nests are relatively wide, flat and shallow. Nests may measure just under 1 m (3.3 ft) in diameter and 20 cm (7.9 in) deep but can easily reach over 1.3 m (4.3 ft) and 30 cm (12 in) with repeated uses. Nests are usually lined with grass, leaves, seedpods and fur as well as odd objects such as newspapers, paper packets and polythene bags. In Kruger National Park, tawny eagles have been recorded using nests of other species of raptor such as white-backed vulture and white-headed vulture. At times, tawny eagles have been known to nest on top of the large communal nests of the white-headed buffalo weaver (Dinemellia dinemelli ). In the Central Karoo region of South Africa, tawny eagles build their nests in large electric transmission towers. Populations of large eagles like the martial eagle and Verreaux's eagle have been recorded breeding on these power pylons since the 1970s. Between 2002 and 2003, 39% of electrical faults recorded on transmission lines were due to large eagle nests. As a result, problem nests were dismantled and rebuilt below the electrical conductors.
Eggs are incubated by the female for 40–44 days, with extreme records of 30 to 45 days, before hatching. Incubation tends to begin with the first egg and may be done exclusively by the female in India but, in African data, the male sometimes briefly relieves here. When the nests are climbed up to, the females are tight sitters, often flying at the very last minute. Green lining may still be added at the incubation stage. Upon hatching, the young apparently have to be constantly brooded or shaded from strong sun in the very open nests. The chicks are initially covered with white down, with a black bill, yellow cere and feet and brown eyes; a thicker white coat is acquired at 2 weeks and 1 week later the 1st feathers appear on scapulars and wing coverts. The young eaglets can stand weakly at about 3 weeks, walk around the nest at 4 weeks and start to wing-flap about a week later. Wing and tail quills sprout rapidly, with feathers appearing down the side of the breast at 4 weeks. By 5 weeks, feathers cover much of the body except for the head and underparts. By week 7, the chick has only a small amount of down feathers remaining and weighs around 2.15 kg (4.7 lb). The rapid development of dorsal feathers is comparable to other raptors that use open nest sites such as snake eagles and secretarybirds. Only one chick usually survives after hatching. This is often due to siblicide, where the older chick fatally wounds the younger chick in the first few days of life. The older sibling weighs around 143 g (5.0 oz) while the younger one weighs about 85 g (3.0 oz) frequently at the point of its demise or disappearance. In southern Africa, there are at least four cases of two fledglings occurring in one nest, however. At around 5 weeks, the eaglet adopts anti-predator behaviours, some laying prone while a novel animal approaches while others adopt a truculent threat posture with feathers raised, gape opened, wings poised to slap and talons barred for slashing. For the first 10 days, the adult female observes the chick very closely, relying on food provisioned by the male. After two weeks, the chick is left alone for 2.5 hours each day, whilst the adults forage. At this point the male may start making direct food deliveries to the eaglet. This is considered a relatively early point to stop attending to the nest for an eagle this size and the nest often soon becomes unsuitably foul with remains. One 39-day-old eaglet was able to tear up its own food already but was still primarily fed by the female. The first flight attempts are around 7–10 weeks but the chick is fully grown and capable of fledging the nest fully after 10–12 weeks. However, the female may remain to shelter during rainstorms around to as late as the fledging stage. The full stage of dependence is ongoing for about 6 weeks after fledging. The young tawny eagle may stay with the parents even until next breeding season. In India at least, after the nesting period, the pairs disperse and leave the nesting area, seldom being seen near the nest until pairing off again initiates in October. A juvenile tawny eagle that was shot at 2 years old was 48 km (30 mi) away from its original nest while 2 juveniles at 5 months and 7 months old were 50 and 34 km (31 and 21 mi) away, respectively.
Nest losses of eggs and young appears to be quite high. Young eaglets often die, at times by their siblings, and if poorly guarded nests are often predated by a probably wide range of predators. Nesting success is driven by quality of habitats and food access. Breeding efforts in Zimbabwe produced 19 young in 26 pair years with a replacement rate of 0.73 young per pair per year. In India, tawny eagles pairs seem to adapt to suboptimal overly sandy habitats by more dispersing nests, and can show similar productivity of chicks per nest as a result. In Hwange National Park, 72.4% of pairs present were thought to breed on average in the course of a year, with an average of 0.61 fledglings produced per effort. This is and other studies support that rainfall is key to productive success in tawny eagles of this area, with far more two egg clutches rather than one egg ones (which usually failed) and less confined breeding periods in years that had greater rainfall. Breeding success, recorded as young per pair per year (ypy), was lower still in Namibia and Tsavo East National Park than in Zimbabwe (0.4, 0.5 and 0.78 ypy respectively). Higher nesting success was found in Zambia, where pair produced a mean of 1 fledgling per nest. Although an extensive study of lifespan are not known to have taken place for the tawny eagle, it is known that these eagles can live up to at least 16 years of age in the wild.
Tawny eagles face a number of threats that affect their breeding behaviour, foraging success and ultimately the survival of individual birds. The most recent and devastating threat to survival occurred on 20 June 2019. The carcasses of 468 white-backed vultures, 17 white-headed vultures, 28 hooded vultures, 14 lappet-faced vultures and 10 cape vultures were found alongside 2 tawny eagles. A total of 537 vultures and 2 eagles were found poisoned in northern Botswana. It is suspected that they died after eating the carcasses of 3 elephants that were laced with poison by poachers. Carcasses are poisoned to ensure that scavengers are unable to aid rangers in the effort to locate poached wildlife. By circling above dead animals, large raptors act as an early detection system for anti-poaching rangers. Poisoning events are far from restricted to Botswana and are thought to be a direct factor in the reduction of tawny eagles as well even in the protected areas of Kruger National Park. In central Namibia, all 5 of the juvenile tawny eagles that were radio-tagged were poisoned by strychnine baits, completely decimating all recruitment of the species in the area. Mysteriously, the populations of bateleurs and tawny eagles in the Maasai Mara appear to be bumping up as opposed to the declines reported elsewhere, seemingly in sync with the worsening declines of vultures on the Maasai.
Further threats to tawny eagles include habitat loss and land-use changes such as intensified cattle grazing, firewood collection and sale and the charcoal industry. Such culling of the spare trees of arid India seem to be the primary driver of less understand decline of tawny eagles in India. A seemingly higher instance of bacterial infections also seems to affecting the tawny eagles of India. Raptor populations are reliant on seasonal rainfall events which influence the survival of prey populations. Climate change is alternating rainfall patterns in the arid regions of Southern Africa and impacting on prey populations. There is a clear correlation between rainfall events and breeding success of tawny eagles. It was found that the projected decline of tawny eagles from climate change, which is already underway, begun via impact population persistence, first effecting population dynamics, the composition of biological communities and finally biodiversity. Electrocutions and collision risks associated with overhead power lines remain a constant threat to large eagles and vultures. Furthermore, the powerline nesting raptors were found to be a significant source of line faulting in the area, causing substantial financial issues. Occasionally, tawny eagles are also killed by flying into various manmade objects such as reservoirs or are killed by automobiles and are at risk at wind turbines in India. The overarching threat to any raptor population is human population increase which causes competition for habitat and food resources. Key to conservation of the tawny eagle population is mitigating the effects of global warming. Also, clearly, the banning of poison baits and the mitigation of dangerous powerlines in eagle-utilized areas is obviously key for the survival of the tawny eagles.
The tawny eagle still occupies a large range. In Africa, it has been estimated that the range of the species covers about 15 million square kilometers, in addition to a range of about 3.1 million square kilometers in Asia. As recently as the 1990s, the global population was thought to possibly range into six figures with a population in Asia at that time thought to be in the hundreds of thousands alone. However, the species is currently listed as Vulnerable on the IUCN list of Threatened species. The current population is far less than half of what it was once thought to be, with only about 100,000 to just under 500,000 individuals thought to persist worldwide. There was a clear decrease in tawny eagle sightings between SABAP and SABAP2 in Southern Africa, occurring in only 323 of 1440 quarter degree grid cells. During close study of the tawny and martial eagle in central Namibia, a precipitous decline was detected in both, with a tawny eagle population that was once regionally numbered about 19 pairs down to 2 known pairs. The once seemingly innumerous population of this species within Kgalagadi Transfrontier Park was known by the 1990s to be down to merely 40 known pairs. Roadside counts conducted in Mali, Niger and Burkina Faso show that although the majority of raptor species are in drastic population decline, only the tawny eagle and snake eagles are surviving outside of protected areas. In India, the tawny eagle was once considered "our commonest eagle" but strong declines have been detected with surveys indicating strongholds like Rajasthan have shown reductions of observed pairs by up to half. According to the producer-scrounger foraging theory, vultures are to some extent reliant on tawny eagles to help locate carcasses. Thus, the conservation of eagles outside protected areas is of vital importance to ensure the survival of vultures.
