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Flores Hawk-eagle
Nisaetus floris

Status: Critically endangered

Population Trend: Declining.

Other Names: Flores Hawk Eagle, Sunda Hawk Eagle.


Nisaetus floris
click to enlarge
Distribution: Indomalayan. Endemic to the LESSER SUNDA ISLANDS (Flores, Sumbawa, Lombok). more....

Subspecies: Monotypic.

Taxonomy: Formerly regarded as a race of the widely distributed N. cirrhatus, but Gjershaug et al. (2004) show that significant morphological differences between this form and other subspecies of cirrrhatus require its recognition as a full species. From their analysis of mtDNA haplotypes in floris (n = 5) and N. cirrhatus limnaetus (n = 5), which occurs on nearby Bali, Gjershaug et al. (2004) found no evidence of mixing. The genetic distance between these two taxa was found to be only 1% (Gamauf et al. 2005), suggesting that they were separated during the Pleistocene. This species was placed in the genus Nisaetus following the recommendation of Helbig et al. (2005), who found that the Asian hawk-eagles formerly assigned to Spizaetus are not related to the New World representatives of that genus. This general concluson was also supported by the molecular studies of Lerner and Mindell (2005), based on the molecular sequences of two mitochondrial genes and one nuclear intron. more....

Movements: Non-migratory, but the present distribution of the species suggests that it must move from island to island on a very local basis.

Habitat and Habits: Gjershaug et al. (2004) and Raharjaningtrah and Rahman (2004) reported that this species is essentially dependent on lowland rainforest, although they recorded it in submontane and montane forest as high as 1,600 m on Flores. It is most often seen flying above the forest canopy along the sides of steep mountain slopes. Gjershaug et al. (op cit.) observed one of these eagles hunting in the middle of a village in early morning on one occasiona, and they also saw it hunting over cultivated landscapes at other times. When seen over cultivated areas, it was always been near intact or semi-intact forest. It soars high over the forest during the heat of the day (Coates and Bishop 1997). more....

Food and Feeding Behavior: Probably feeds on small mammals, birds, and lizards, like closely related eagle species (Coates and Bishop 1997).

Breeding: Verheijen (1964) recorded active nests on West Flores in March (1), April (2), May (1), and August (1), but did not provide further details. Display flights and copulation were observed on Flores in June and July 2003 by J.-M. Thiollay (in litt. to Gjershaug et al. 2004), suggesting that breeding takes place during the dry season. Gjershaug et al. (op cit.) were told by villagers in Mbeliling, Flores that a large tree cut down in August contained a nest with a large eagle nestling (probably of this species), also indicating breeding during the dry season. The nest and eggs are undescribed.

Conservation: This "new" species is presently declining due to deforestation, persecution (because it kills chickens), and capture for the live bird trade (Gjershaug et al. 2004, Raharjaningtrah and Rahman 2004). The latter authors mentioned that some of the persecution is by persons coming to the Lesser Sundas from as far away as Java and Bali, probably in connection with the live bird and taxidermy trades. Trainor and Lesmana (2000) and Trainor (2002) also mentioned that birds are captured for the cagebird trade and shot for display specimens. The former authors knew of two mounted birds that were sold in Ruteng, and Raharjaningtrah and Rahman (op cit.) expressed concern that publicity about the rarity of this eagle might lead to more shooting of birds for collectors of taxidermied specimens. Gjershaug et al. (op cit.) concluded that "protected areas in the species's range are presently too small for its long-term survival." Categorized as Critically Endangered by BirdLife International. more....

Population Estimates: From their field studies of this species, Gjershaug et al. (2004) concluded that the present population of this species is probably less than 100 pairs, based on their estimate of territory size as ca. 40 km². Raharjaningtrah and Rahman (2004) independently estimated the population at 73-75 pairs, based on their extrapolation from an estimated home range size of 38.5 km² (n = 3). On that basis, they suggested that there might be 10 pairs on Lombok, 38 pairs on Sumbawa, and 27 pairs on Flores.

Important References: 
Amadon, D. 1953. Remarks on the Asiatic hawk-eagles of the genus
  Spizaetus. Ibis 95:492-500.
Butchart, S.H.M., T.M. Brooks, C.W.N. Davies, G. Dharmaputra, G.C.L.
  Dutson, J.C. Lowen, and A. Sahu.
1996. The conservation status of forest
  birds on Flores and Sumbawa, Indonesia. Bird Conservation International
  6:335-370.
Coates, B.J., and K.D. Bishop. 1997. A guide to the birds of Wallacea.
  Dove Publications, Alderley, Queensland, Australia.
Gamauf, A., J.-O. Gjershaug, N. Røv, K. Kvaløy, and E. Haring. 2005.
  Species or subspecies? The dilemma of taxonomic ranking of some South-East
  Asian hawk-eagles (genus Spizaetus). Bird Conservation International
  15:99-117.
Gjershaug, J.O.. 2006. Taxonomy and conservation status of hawk-eagles
  (Genus Nisaetus) in South-east Asia. Ph.D. dissertation, Norwegian
  University of Science and Technology, Trondheim, Norway.
  http://urn.ub.uu.se/resolve?urn=urn:nbn:no:ntnu:diva-413
  (2008-03-03)
Gjershaug, J.O., K. Kvaløy, N. Røv, D.M. Prawiradilaga, U. Suparman, and
  Z. Rahman.
2004. The taxonomic status of Flores Hawk Eagle Spizaetus flores.
  Forktail 20:55-62.
Raharjaningtrah, W., and Z. Rahman. 2004. Study on the distribution,
  habitat and ecology of Flores Hawk-eagle Spizaetus cirrhatus floris in
  Lombok, Sumbawa, Flores, Komodo, and Rinca Islands, Nusa Tenggara,
  Indonesia. Annual Report of Pro Natura Fund 13:177-191.
Trainor, C. 2002. Birds of Gunung Tambora, Sumbawa, Indonesia: effects of
  altitude, the 1815 cataclysmic volcanic eruption and trade. Forktail
  18:49-61.
Trainor, C., and D. Lesmana. 2000. Exploding volcanoes, unique birds,
  gigantic rats and elegant ikat: identifying sites of international
  biodiversity significance on Flores, Nusa Tenggara. PKA/BirdLife
  International/World Wildlife Fund, Bogor, Indonesia.
Verheijen, J.A. 1964. Breeding season on the Island of Flores. Ardea
  52:194-201.
Verhoeye, J., and D.A. Holmes. 1998, The birds of the islands of Flores --
  a review. Kukila 10:3-59.
more....

Researchers:
Gamauf, Anita
Gjershaug, Jan Ove
Suparman, Usep

Last modified: 10/7/2012

Recommended Citation: Global Raptor Information Network. 2017. Species account: Flores Hawk-eagle Nisaetus floris. Downloaded from http://www.globalraptors.org on 23 Mar. 2017








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