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Changeable hawk-eagle

The Changeable hawk-eagle (also known as the crested hawk-eagle; Nisaetus cirrhatus) is a medium-sized in the family , characterized by its brown upperparts, whitish underparts with heavy dark streaking, and variable presence of a short on the head, with adults typically measuring 51–82 cm in length and weighing 1,300–1,900 g. This species exhibits variation across its , including crested and crestless forms, and is distinguished by its yellow to orange eyes in adults and a diet primarily consisting of birds, mammals, and reptiles. Native to South and Southeast Asia, the Changeable hawk-eagle has a broad distribution spanning countries such as , , , , , , , , the Philippines, and , with an extent of occurrence estimated at over 15 million km². It inhabits a variety of forested environments, including dry deciduous and semi-evergreen forests, logged second-growth areas, savanna woodlands, and even cultivated landscapes, typically at elevations from to 1,500 m, though occasionally higher. The species is adaptable and often perches in open woodland or along forest edges, where it hunts from a perch or in flight, preying on items like squirrels, snakes, and gallinaceous birds. Taxonomically, N. cirrhatus was first described by J.F. Gmelin in 1788 and comprises at least five , including the nominate N. c. cirrhatus in peninsular , N. c. limnaeetus across northern to the Greater Sundas and , N. c. ceylanensis in , N. c. andamanensis in the , and N. c. vanheurni on Island, though recent studies suggest potential for further taxonomic revision based on , vocalizations, and in overlapping regions. occurs seasonally, with pairs constructing large stick nests in tall trees and laying a single that hatches after about 50 days of , followed by fledging at 62–68 days. Although populations are decreasing overall and the is classified as Least Concern by the IUCN, it faces threats from habitat loss, fragmentation, and in some areas.

Taxonomy

Classification history

The changeable hawk-eagle was originally described by the German naturalist Johann Friedrich Gmelin in 1788 as Falco cirrhatus in the 13th edition of Systema Naturae. Following its initial placement in the genus Falco, the species was later classified within Spizaetus, reflecting its hawk-eagle morphology and shared traits with other Old World raptors. Molecular phylogenetic analyses conducted between 2005 and 2007 revealed significant paraphyly in the genus Spizaetus, with Asian hawk-eagles, including the changeable hawk-eagle, forming a distinct clade separate from Neotropical species. Specifically, Gamauf et al. (2005) examined mitochondrial DNA sequences from the cytochrome b gene and control region across the S. cirrhatus complex, identifying low genetic distances (0–1.5%) within the group but clear divergence from New World Spizaetus taxa. Haring et al. (2007) corroborated this through broader analyses of mitochondrial markers, attributing morphological similarities among hawk-eagles to convergent evolution and recommending the resurrection of Nisaetus for the Asian lineage, to which the changeable hawk-eagle was transferred. Within the N. cirrhatus complex, the Flores hawk-eagle (N. floris) was recognized as a distinct in 2004 based on pronounced morphological differences, including diagnostic white patches on the primaries, a juvenile-like , and larger body size compared to continental forms. This separation was supported by genetic data from Gamauf et al. (2005), which showed floris forming a distinct , indicating despite close phylogenetic proximity to N. cirrhatus. A comprehensive integrative taxonomic study by Gjershaug et al. in 2020 focused on the crested (N. c. cirrhatus) and crestless (N. c. limnaeetus) forms in , using , , , and vocalizations. The analysis revealed weak , with approximately 30% of individuals exhibiting intermediate crest lengths suggestive of hybridization or , and limited attributable to largely allopatric distributions rather than strong barriers. loci and mitochondrial markers showed no fixed genetic differences, leading to the recommendation that the forms remain conspecific under the biological species concept. The is commonly known as the changeable hawk-eagle or crested hawk-eagle, with "changeable" deriving from its extensive polymorphism, ranging from to morphs that vary with , molt, and individual variation.

The changeable hawk-eagle (Nisaetus cirrhatus) is currently recognized as comprising five , distinguished primarily by variations in crest development, coloration and patterning, and subtle differences in body size across their respective ranges. The nominate subspecies, N. c. cirrhatus (Gmelin, 1788), occurs throughout the south of the Gangetic Plain, where it is notably crested with a prominent measuring 90–120 mm in length; dark individuals, featuring extensively dark under, are commonly observed in this population. N. c. limnaeetus (Horsfield, 1821) is distributed across , from the Himalayan foothills through Indochina, the , Greater Sundas, and portions of the southern ; birds of this subspecies typically exhibit reduced or absent crests (37–65 mm) and more uniform upperpart plumage with banded underparts. N. c. andamanensis (Tytler, 1865) is restricted to the , with a higher prevalence of pale morphs displaying lighter overall tones in the underplumage compared to mainland forms. N. c. vanheurni (Junge, 1936), found on Island off northwestern , represents an intermediate form in size and development, bridging characteristics of crested and crestless populations. N. c. ceylanensis (Gould, 1840) inhabits and closely resembles N. c. cirrhatus in its well-developed crest and tendency toward darker plumage tones, though it is slightly smaller on average. Morphological variation among these subspecies includes differences in crest prominence, with the and Sri Lankan forms generally more crested than their Southeast Asian counterparts, as well as shifts in tones from darker, streaked patterns in southern populations to paler or more banded appearances in island and continental Southeast Asian groups. Body size also varies, with females across typically 20–22% larger than males in linear measurements and weight, though there is considerable overlap in overall dimensions ( 51–82 cm, 100–160 cm); for instance, N. c. vanheurni shows intermediate body proportions relative to the smaller N. c. andamanensis and larger N. c. limnaeetus. A 2020 integrative taxonomic study utilizing and morphometric data revealed limited between the two Indian (N. c. cirrhatus and N. c. limnaeetus) (FST = 0.042; mtDNA divergence 0.4–1.2%), indicative of recent separation approximately 200,000 years ago and ongoing hybridization in contact zones, yet supported retaining their status due to consistent morphological distinctions and partial .

Description

Morphology and plumage

The Changeable hawk-eagle (Nisaetus cirrhatus) is a medium-sized with a body length of 51–82 cm, of 100–160 cm, and weight ranging from 1.3–1.9 kg. Females are noticeably larger than males, showing sexual size dimorphism across measurements such as wing length (males 340–425 mm, females 380–450 mm) and bill length (males 26.6–31.9 mm, females 27.4–36.1 mm). This exhibits a robust structure adapted for habitats, featuring broad, rounded wings suited for maneuvering through dense , a short rounded (240–300 mm long) with dark barring, and a strong hooked bill (greyish-) equipped with a prominent yellow cere. The legs are yellow with feathered tarsi (94–123 mm long) for protection, and the head bears a of four black feathers, which can reach up to 12 cm in length in some but may be shorter or absent in others. Plumage shows significant variation across individuals, ages, regions, and , contributing to the species' "changeable," as it alters with moult cycles. Adults occur in light and dark morphs: the light morph has dark brown upperparts, a whitish and underparts heavily streaked with dark brown, and tones on the head and neck in some races; the dark morph is overall sooty brown with paler outer wing feathers and less contrast on the underparts. Intermediate forms blend these traits, while juveniles are distinct with cleaner white underparts showing sparse barring and streaking, paler heads, and greenish-yellow irises that darken to yellow or orange in adults. As immatures progress through moults, they acquire more adult-like patterning, with differences such as darker bellies in N. c. cirrhatus versus banded vents in N. c. limnaeetus.

Vocalizations

The changeable hawk-eagle produces a variety of vocalizations, primarily during the season, though it is generally silent outside of these periods. The primary call consists of a series of 4-6 whistled "wheep" or "ki-ki-ki" , often delivered in flight or during territorial displays. For threats, the bird emits a rapid, sharp described as "kik-kik-kik," which serves to deter potential intruders or predators. During , pairs engage in duets featuring low hoots and piercing screams as part of rituals, with these vocalizations helping to reinforce pair bonds and defend nesting territories. Vocalizations are typically louder and more frequent in dense forest environments to carry over , and recordings indicate regional dialects, such as a higher-pitched variant in populations compared to those in .

Similar species

The changeable hawk-eagle is frequently confused with other raptors in its due to overlapping habitats and variations, particularly its two morphs (pale and dark), which can affect in flight or at rest. Key distinguishing field marks include its small-headed appearance in flight, a floppy or crest that may be prominent or nearly absent, and streaked underbody patterns rather than heavy barring. It is often mistaken for the , especially in the dark morph, but the hawk-eagle exhibits rounder wings, a shorter , feathered tarsi, and a more eagle-like flight silhouette with broader, flatter wings during soaring. In contrast, the has longer, more rectangular wings, a longer forked , and bare tarsi, contributing to a slimmer profile. Compared to the mountain hawk-eagle, the changeable hawk-eagle has broader wings with less barring on the underwing, a variable that can be floppy or reduced, and streaked underparts rather than the mountain species' heavy rusty barring on the belly. The mountain hawk-eagle, in turn, features a fixed short and more pointed wings with greater underwing barring. The , particularly when viewed distantly, may resemble the dark morph changeable hawk-eagle, but the latter is smaller in size, shows paler underparts in its light morph, and has less emphasis on prolonged soaring with a more agile flight style. The is larger overall, uniformly dark with long, slender, fingered wings, and lacks a .

Distribution and habitat

Geographic range

The changeable hawk-eagle (Nisaetus cirrhatus) has a broad distribution across the and , ranging from , , , , and through Indochina (including , , , and ) to the , Greater Sundas (including and ), , , and the . It is absent from extreme northern regions of the and certain isolated islands beyond its core range. Five subspecies are recognized within this range, each with distinct distributions: N. c. cirrhatus (nominate) occurs in peninsular ; N. c. limnaeetus is found from the Himalayan foothills of northern through Indochina, the , Greater Sundas, and into the southern ; N. c. ceylanensis is endemic to ; N. c. andamanensis inhabits the ; N. c. vanheurni is restricted to Simeulue Island off western . These distributions reflect historical forest continuity, though has led to allopatric ranges for some , such as N. c. cirrhatus and N. c. limnaeetus in . The occurs from up to 2,200 m in , though it is primarily recorded below 1,500 m across its range. Ongoing observations indicate a stable presence in protected areas within its range, such as in .

Habitat preferences

The changeable hawk-eagle primarily inhabits a variety of tropical and subtropical types, including moist lowland , semi-evergreen , and dry . It also utilizes edges, plantations, and arable lands adjacent to forested areas, as well as inland wetlands such as swamps and marshes near permanent rivers and streams. These habitats provide the dense cover and structural diversity essential for perching and nesting. This species demonstrates considerable adaptability, tolerating in logged forests, dry savannas with scattered trees, and even rural gardens or cultivated areas like rice fields, provided there are suitable perches. However, it generally avoids open grasslands lacking arboreal structure, favoring environments that balance canopy cover with open hunting grounds. Such flexibility allows it to persist in moderately modified landscapes across its Asian range. In terms of elevation and climate, the changeable hawk-eagle prefers lowland wet forests in humid tropical zones, ranging from up to 1,500 meters, with occasional records to 2,200 meters at montane forest edges. It thrives in subtropical to tropical moist conditions but can extend into drier woodlands where supports prey availability. Habitat fragmentation poses significant challenges, as the species relies on areas with tall, mature trees for perching and hunting; populations decline in heavily logged regions where such features are lost to destruction and human disturbance. This vulnerability underscores the importance of maintaining connected forest patches to support its ecological needs.

Behavior and ecology

Diet and foraging

The Changeable hawk-eagle maintains an opportunistic, carnivorous dominated by vertebrates, with regional variations in prey composition reflecting local availability. In a study at a nest in Gunung Halimun-Salak National Park, , , adults delivered 21 identifiable prey items, of which reptiles accounted for 62% (13 items, primarily snakes and agamid lizards), birds 24% (5 items, including a domestic and a white-breasted waterhen), and mammals 14% (3 items, such as squirrels). In contrast, observations in , , revealed a higher reliance on birds relative to reptiles and mammals, though exact proportions were not quantified beyond noting birds as the dominant class. Avian prey commonly includes medium-sized species such as pigeons, doves, common mynas, red-vented , jungle fowl, , and drongos, often comprising 50% or more of the in populations. Mammals form another key component, featuring arboreal and ground-dwellers like palm squirrels, rats, hares, flying foxes (bats), and occasionally juvenile monkeys or mongooses. Reptiles, targeted especially in wetter habitats, encompass (e.g., common bronzeback), (e.g., ), , and monitor lizards. Prey sizes range from small vertebrates to medium animals up to hare-sized, which the eagle captures and either swallows whole or tears apart with its hooked bill. As a diurnal predator, the Changeable hawk-eagle primarily employs perch-hunting from concealed canopy branches or exposed perches along forest edges, where it remains motionless while scanning for movement below. Upon detecting prey, it executes short, low-level glides, stoops, or rapid dives to seize victims with powerful talons, demonstrating in dense environments. This strategy suits its preference for arboreal and prey, with occasional scavenging of carrion supplementing live captures.

Reproduction

The changeable hawk-eagle forms monogamous pairs that maintain year-round territories, with breeding seasons varying by region to align with local prey availability and climatic conditions. In , breeding occurs from November to May, peaking in January–March, while in , , , and it spans December to May; on , the season is more restricted to . behaviors include aerial displays with synchronized soaring and diving maneuvers, accompanied by vocal duets and food passes between mates to strengthen pair bonds. Nests are large platforms constructed from sticks and lined with fresh green leaves, typically placed in the crowns of tall emergent trees at heights of 20–40 m, often on slopes near water sources, with observed nests averaging 88 cm long and 54 cm wide, placed in trees averaging 149 cm in diameter. Pairs frequently reuse the same nest site annually or build alternates within the territory. A single white , occasionally marked with reddish-brown spots, is laid per ; incubation lasts approximately 50 days and is performed by both parents, with the female undertaking the majority of the duties while the male provides food. The single hatches after and is brooded by the for the first few weeks, with both parents delivering prey—primarily reptiles, , and small mammals—to the nest. Nestlings grow rapidly, reaching full size by about 52 days and fledging at 60–68 days old, though they remain dependent on parental provisioning for an additional 2–3 months while learning to hunt. In undisturbed habitats, fledging success is high, with studies reporting approximately 67% of monitored nests producing fledged young.

Daily activity and movements

The changeable hawk-eagle (Nisaetus cirrhatus) is a diurnal , active primarily during daylight hours, with notable peaks in activity during the morning and late afternoon, aligning with crepuscular periods for enhanced hunting efficiency. This pattern supports its predation strategy, where individuals perch in elevated positions to scan for prey before launching sudden dives. Pairs maintain year-round territories, defending home ranges estimated at 33–155 km² through aggressive aerial displays involving vertical ascents followed by stooping dives, often accompanied by loud vocalizations to deter intruders. The species exhibits solitary or paired outside of breeding, with individuals fiercely protecting their domains against conspecifics or other raptors via these displays and calls. Primarily resident, the changeable hawk-eagle shows no evidence of long-distance migrations, remaining within established territories throughout the year. Some populations exhibit local movements or altitudinal shifts in response to seasonal changes in food availability or environmental conditions, while juveniles may disperse short distances to establish new ranges.

Conservation

IUCN status

The changeable hawk-eagle (Nisaetus cirrhatus) is classified as Least Concern on the , a status it has held since 1988. It was last assessed in 2020, with no updates as of 2025. This classification is due to the species' extremely large geographic range, with an extent of occurrence exceeding 15 million km², which far surpasses the thresholds for Vulnerable status under IUCN criterion B (range size). Additionally, it does not meet the population decline criteria under criterion A, requiring less than 30% reduction over three generations, despite a suspected overall decreasing trend; no precise global population estimate is available, though it is described as locally common. Regionally, the species is protected under Schedule I of India's Wildlife (Protection) Act, 1972, affording it the highest level of legal safeguards. In , it remains widespread and is considered stable in many areas due to its occurrence in protected forests and reserves across the region. The primary threats to the changeable hawk-eagle (Nisaetus cirrhatus) stem from and fragmentation, driven by for logging and agricultural expansion, with particularly acute impacts in key range countries such as and . In , the species has become scarce on due to extensive forest loss, while in , ongoing conversion of forests to farmland exacerbates habitat degradation. Human persecution, including shooting, further endangers individuals, especially in agricultural landscapes. Secondary threats include nest disturbance from increased human activities near breeding sites. No significant outbreaks affecting the have been documented in recent assessments. Overall, the changeable hawk-eagle remains stable and is classified as Least Concern by the IUCN, reflecting its wide and adaptability. However, the is suspected to be declining locally in fragmented habitats, underscoring vulnerability in modified landscapes despite the ' resilience to use. Conservation efforts include legal protection within reserves such as in , , where the species benefits from habitat safeguards against logging. The changeable hawk-eagle is also regulated under Appendix II to control international trade. Citizen science monitoring via eBird reveals consistent sightings across its range through 2025, supporting ongoing population assessments.

References

  1. [1]
    Changeable Hawk-Eagle | The Peregrine Fund
    The Changeable Hawk-eagle is found throughout a large part of Asia including in the countries of Bangladesh, Brunei Cambodia, India, Indonesia, Malaysia, ...Missing: taxonomy distribution
  2. [2]
    Nisaetus cirrhatus (J.F. Gmelin, 1788) | Species
    A medium sized bird of prey with brown above and white with brown barring below. Some sub-species have a crest of four feathers. It is called "changeable" ...
  3. [3]
    Changeable Hawk-eagle Nisaetus Cirrhatus Species Factsheet
    Habitat classification ; Forest, Subtropical/Tropical Moist Lowland, Resident ; Savanna, Dry, Resident ; Wetlands (inland), Bogs, Marshes, Swamps, Fens, Peatlands ...
  4. [4]
    Nisaetus cirrhatus (Crested Hawk-Eagle) - Avibase
    Nisaetus cirrhatus limnaeetus: northern India to Indochina, Malaya, Greater Sundas, and Philippines; Nisaetus cirrhatus vanheurni: Simeulue Island (off western ...Missing: habitat | Show results with:habitat
  5. [5]
    Species or subspecies? The dilemma of taxonomic ranking of some ...
    The dilemma of taxonomic ranking of some South-East Asian hawk-eagles (genus Spizaetus). Published online by Cambridge University Press: 23 May 2005. ANITA ...
  6. [6]
    Convergent evolution and paraphyly of the hawk‐eagles of the ...
    May 25, 2007 · The phylogenetic relationships within the New and Old World hawk-eagle assemblage (genus Spizaetus; Aves: Accipitridae) were studied using ...
  7. [7]
    (PDF) The taxonomic status of Flores Hawk Eagle Spizaetus floris
    It has diagnostic white patches on the upperside of the inner parts of the primaries, a juvenile-like adult plumage, and it is much larger than limnaeetus. It ...
  8. [8]
    Integrative taxonomy of the Changeable Hawk-Eagle Nisaetus ...
    Jun 9, 2020 · (2005) Species or subspecies? The dilemma of taxonomic ranking of some south-east Asian hawk-eagles (genus Spizaetus). Bird Conservation ...
  9. [9]
    Changeable Hawk-Eagle Nisaetus cirrhatus - Birds of the World
    This account summarizes the life history of the Changeable Hawk-Eagle, including information relating to its identification, systematics, distribution, habitat, ...
  10. [10]
  11. [11]
    [PDF] Taxonomy and conservation status of hawk-eagles (genus Nisaetus ...
    Rasmussen & Anderton (2005) found that there are some consistent morphological and vocal differences between cirrhatus and limnaeetus. The difference in crest ...<|control11|><|separator|>
  12. [12]
    [PDF] Integrative taxonomy of the Changeable Hawk-Eagle Nisaetus ...
    In this study we examine species limits in the Nisaetus cirrhatus complex in India using an integrative taxonomic approach. (Dayrat 2005) based on novel ...
  13. [13]
    Changeable Hawk-Eagle Nisaetus cirrhatus - eBird
    Medium-sized eagle with massive rounded wings. Appears very small-headed in flight. Name is slightly misleading, as there are only really two color morphs, ...Missing: subspecies list
  14. [14]
    Changeable Hawk-eagle - Oiseaux-Birds
    DESCRIPTION: Changeable Hawk-eagle adult has brown upperparts, with wing coverts generally paler. Tail is pale brown, barred with 3 or 4 narrow dark bars.
  15. [15]
    Species Spotlight: Changeable Hawk-eagle - 10,000 Birds
    Sep 12, 2025 · The scientific name Nisaetus cirrhatus characterizes the bird as “curly-haired” (cirrhatus). Apparently, ChatGPT is not widely used at HNG ...Missing: subspecies | Show results with:subspecies<|control11|><|separator|>
  16. [16]
    Changeable Hawk-Eagle (Nisaetus cirrhatus) :: xeno-canto
    120 foreground recordings and 15 background recordings of Nisaetus cirrhatus . Total recording duration 53:45. Results format: detailed; concise · sonograms. 1 ...
  17. [17]
  18. [18]
    Crested Honey Buzzard - Birds of Singapore
    Often confused with the Changeable Hawk-eagle, from which it can be told apart by its smaller head, less rounded (longer and more rectangular) wings, longer ...
  19. [19]
    Mountain hawk-eagle (Nisaetus nipalensis) - Thai National Parks
    While soaring, changeable hawk-eagles tend to have flatter wing shape than mountain hawk-eagles. Changeable adults also have streaking rather than heavy rusty ...Missing: identification | Show results with:identification
  20. [20]
    Black Eagle (Ictinaetus malaiensis) identification - Birda
    Similar Species. The Black Eagle can be confused with the dark form of the Changeable Hawk-Eagle (Nisaetus cirrhatus), but its wing shape is a reliable ...
  21. [21]
    Changeable hawk-eagle (Nisaetus limnaeetus) - Thai National Parks
    Their distribution includes nations and areas such as Sri Lanka, Himalayan foothills (Garhwal to Assam), southern Nepal and Bhutan east through Myanmar, Burma, ...
  22. [22]
    Bandipur National Park bird checklist - Avibase
    Legge's Hawk-Eagle, Nisaetus kelaarti. Changeable Hawk-Eagle, Nisaetus cirrhatus. Rufous-bellied Eagle, Lophotriorchis kienerii, Near-threatened. Black Eagle ...
  23. [23]
    Crested Hawk-Eagle (Nisaetus cirrhatus) - Planet of Birds
    Aug 27, 2011 · The Crested or Changeable Hawk-eagle is found in India, Ceylon and Tropical continental Asia east to Indonesia and the Philippines. Habitat. In ...Missing: geographic | Show results with:geographic
  24. [24]
    [PDF] Eagles Nisaetus cirrhatus in Gunung Halimun-Salak National Par
    Although we identified only 21 items brought to the 2013 nest in GHSNP, reptiles predominated (62%) while mammals were the least well represented taxon. This ...
  25. [25]
    Diet and habitat affinities in six raptor species in India
    Oct 29, 2018 · The study was conducted in Maharashtra State, Central India (Fig. ... Changeable Hawk-eagle (Nisaetus cirrhatus, n = 14), and Red-necked ...
  26. [26]
    Foraging/Hunting Behaviour of the Changeable Hawk-Eagle ...
    Nov 24, 2022 · Changeable Hawk-Eagles are known to take a variety of animal prey which include reptiles (snakes, frogs, lizards), birds (chickens, White- ...
  27. [27]
    Nest cycle and nestling development of a pair of Changeable Hawk ...
    In total, 387 leftovers of food were found. Birds represented 52%, mammals 42% and other animals (insect, reptiles etc.) 6% of prey. The population of goshawk ...
  28. [28]
    None
    ### Summary of Changeable Hawk-Eagle Reproduction in Gunung Halimun Salak National Park
  29. [29]
    Changeable Hawk-Eagle | Nisaetus cirrhatus
    Activity period : Primarily active during the day, with peak activity in the morning and late afternoon. Identification and description: The Changeable Hawk ...
  30. [30]
    Changeable hawk eagle - Birds of Indian Subcontinent
    May 9, 2024 · ... movements in response to changes in food availability or environmental conditions. These migrations are typically localized and may involve ...
  31. [31]
    Phylogenetic study of Changeable Hawk-eagle (Nisaetus cirrhatus ...
    The main objectives of this study were to obtain COI gene sequences of 5 individuals. (4 intermediated phase and 1 dark phase) eagles and to construct their ...
  32. [32]
    Changeable Hawk-Eagle - Facts, Diet, Habitat & Pictures on ...
    Changeable hawk-eagles have a carnivorous diet. They show a slight preference for birds as prey, but also freely take various mammals, reptiles, and some other ...Missing: composition items
  33. [33]
    Changeable Hawk Eagle | State of India's Birds
    Conservation Categories. Global Red List: Least Concern. Wild Life Protection Act: Schedule-I. Photo: Bhaarat Vyas. p.. Changeable Hawk Eagle. p.
  34. [34]
    Comparison of point and roadside transect methods to evaluate the ...
    Dec 8, 2021 · Major threats i.e., collision with man-made objects [4], poisoning ... (Nisaetus cirrhatus) were very few and hence they were not used in ...