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Pygmy Eagle
Aquila weiskei

Status: Lower risk

Population Trend: Unknown.

Other Names: New Guinea Hawk-eagle.

Aquila weiskei
click to enlarge
Distribution: Australasian: NEW GUINEA and the MOLUCCAS. more....

Subspecies: Monotypic.

Taxonomy: The study of Lerner and Mindell (2005), based on molecular sequences of two mitochondrial genes and one nuclear intron, showed that this form, which has usually been treated as a subspecies of H. morphnoides, is actually more closely related to the Booted Eagle, A. pennata. The amount of sequence variation between A. morphnoides and A. weiskei is as much as found between unquestioned species in their analysis. This result was also obtained by Bunce et al. (2005), as a by-blow of their study of the relationships of the extinct New Zealand Eagle, Aquila (Hieraaetus) moorei, and they pointed out that weiskei deserves species rank because it differs from other Aquila species genetically, geographically and morphologically. A more detailed study by Gjershuag et al. (2009) confirmed these findings, based on both molecular, morphological, and plumage characters. Therefore, weiskei is treated here as a full species. The vernacular name "Pygmy Eagle," was suggested by Jan Ove Gjershaug, based on the small size of this newly recognized species. BirdLife International has suggested the vernacular "New Guinea Hawk-eagle." Most raptor systematists (e.g., Wink and Sauer-Gürth 2004, Gjershaug 2006) and national taxonomic committees (e.g., Sangster et al. 2005) now favor merging the species formerly assigned to Hieraaetus into Aquila, and they are followed here.

Movements: Unknown, but probably non-migratory.

Habitat and Habits: In New Guinea, it frequents primary forest, gallery forest, monsoon forest, and forest edges, usually seen soaring above the forest, flying low over the canopy, or perching fairly high up with a clear view (Coates 1985).

Food and Feeding Behavior: Sometimes attacks groups of the Grey Crow Gymnocorvus tristis (Coates 1985).

Breeding: The breeding habits are poorly known. One member of a pair was observed performing ritual collecting of sticks and moss in the Baiyer River area in March, late in the wet season (Mackay 1980). The eggs are white or bluish-white, unmarked or sparsely streaked and blotched with reddish-brown (Coates 1985).

Conservation: There is little information on the status of this species, but it is regarded as fairly common or common by Jan Ove Gjershaug (pers. comm.), based on his field experience in New Guinea. Coates (1985) described it as well distributed, but scarce, in New Guinea, and Coates and Bishop (1997) regarded it as rare or uncommon in the Moluccas, where it has seldom been recorded. It is probably suffering declines in some areas as a result of deforestation, but little else is known about possible threats. BirdLife International categorizes it as a species of Least Concern, but this classification must be regarded as tentative.

Population Estimates: There are no published population estimates for this newly recognized species, and the population category (1,000 to 10,000 total individuals) assigned here is largely speculative.

Important References: 
Beehler, B.M., T.K. Pratt, and D.A. Zimmerman. 1986. Birds of New Guinea.
  Princeton University Press, Princeton, NJ.
Bunce, M., M. Szulkin, H.R.L. Lerner, I. Barnes, B. Shapiro, A. Cooper,
  and R.N. Holdaway.
2005. Ancient DNA provides new insights into the
  evolutionary history of Ne2w Zealand's extinct giant eagle. PLOS Biology
  3(1. DOI: 10.1371/journal.pbio.0030009.
Coates, B.J. 1985. The birds of Papua New Guinea. Vol. 1. Non-passerines.
  Dove Publications, Alderley, Queensland, Australia.
Coates, B.J. 2001. Birds of New Guinea and the Bismarck Archipelago: a
  photographic guide. Dove Publications, Alderley, Queensland, Australia.
Gjershaug, J.O. 2006. Taxonomy and conservation status of hawk-eagles
  (genus Nisaetus) in south-east Asia. Ph.D. thesis, Norwegian University of
  Science and Technology, Trondheim, Norway;
Gjershaug, J.O., H.R.L. Lerner, and O.H. Diserud. 2009. Taxonomy and
  distribution of the Pygmy Eagle Aquila (Hieraaetus) weiskei
  (Accipitriformes: Accipitridae). Zootaxa 2326:24-38.
Lerner, H.R., and D.P. Mindell. 2005. Phylogeny of eagles, Old World
  vultures, and other Accipitridae based on nuclear and mitochondrial DNA.
  Molecular Phylogenetics and Evolution 37:327-346.
Parry, S.J. 2001. The booted eagles (Aves: Accipitridae): perspectives in
  evolutionary biology. Ph.D. dissertation, University College, London.
Peckover, W.S., and L.W.C. Filewood. 1976. Birds of New Guinea and
  tropical Australia. A.H. & A.W. Reed, Sydney, Australia.
Rand, A.L., and E.T. Gilliard. 1967. Handbook of New Guinea birds.
  Weidenfeld & Nicolson, London.

Sites of Interest:
BirdLife International
Fact sheet.

Last modified: 2/17/2011

Recommended Citation: Global Raptor Information Network. 2020. Species account: Pygmy Eagle Aquila weiskei. Downloaded from http://www.globalraptors.org on 7 Jul. 2020

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