Wikipedia:Haast's Eagle
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 Artist's rendition of a Haast's Eagle
attacking moa. |
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Prehistoric
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| Harpagornis moorei Haast, 1872 |
Haast's Eagle (Harpagornis moorei), was a massive, now extinct eagle that once lived on the South Island of New Zealand. It is the largest eagle known to have existed. It is believed that the Māori called it Pouakai; the often-cited name Hokioi (or hakawai) refers to the aerial display of the New Zealand Snipe — specifically, the extinct South Island subspecies.[1]
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Description
Haast's Eagles were the largest true raptors, outsizing even the largest living vultures. Females are believed to have weighed 10 to 15 kg (22 to 33 lb), and males 9 to 12 kg (20 to 26 lb). They had a relatively short wingspan of roughly 2.6 to 3 m (8 to 10 ft). This wingspan was similar to that of some surviving eagles (the largest Golden Eagles and Steller's Sea Eagles) – although even the largest extant eagles are about 40% smaller in body size. Short wings may have aided Haast's Eagle when hunting in the dense scrubland and forests of New Zealand. Haast's Eagle is sometimes portrayed as having evolved towards flightlessness, but this is not so; rather, it represents a departure from its ancestors' mode of soaring flight toward higher wing loading and increased maneuverability. The strong legs and massive flight muscles would have enabled the birds to take off with a jumping start from the ground, despite their great weight. The tail was almost certainly long (up to 50 cm (20 inches), in female specimens) and very broad, further increasing maneuverability and compensating for the reduction in wing area by providing additional lift.[2] Total length was perhaps up to 1.4 m (4.7 ft) in females, with a standing height of around 90 cm (about 3 ft) tall or even slightly more. Haast's Eagle preyed on large, flightless bird species, including the moa which was up to 15 times its weight.[2] It attacked at speeds up to 80 km/h (50 mph), often seizing its prey's pelvis with the talons of one foot and killing with a blow to the head or neck with the other. Its size and weight indicate a bodily striking force equivalent to a cinder block landing on the target from a height of 25 m.Its large beak was used to rip into the internal organs and death was induced by blood loss. In the absence of other large predators or scavengers, a Haast's Eagle could have easily monopolised a single large kill over a number of days.
Extinction
Early human settlers in New Zealand (the Māori arrived about 1,000 years ago) also preyed heavily on large flightless birds including all moa species, eventually hunting them to extinction. This caused the Haast's Eagle to become extinct around 1400[3] when the last of its food sources were depleted. It may also itself have been hunted by humans.
A noted explorer, Charles Douglas, claims in his journals that he had an encounter with two raptors of immense size in Landsborough River valley (probably in the 1870s), and shot and ate them.[4] These birds might have been a last remnant of the species, but this is very unlikely; there had not been suitable prey for a population of Haast's Eagle to maintain itself for about half a millennium,[citation needed] and 19th century Māori lore was adamant that the pouakai was a bird not seen in living memory. Still, Douglas' observations on wildlife are generally trustworthy; a more probable explanation, given that the alleged three-metre wingspan of Douglas' birds is unlikely to have been more than a rough estimate, is that the birds were Eyles' Harriers. This was the largest known harrier (the size of a small eagle) — and a generalist predator — and although it is also assumed to have gone extinct in prehistoric times, its dietary habits alone make it a more likely candidate for late survival.[original research?]
Until recent human colonisation, the only terrestrial mammals found on New Zealand were three species of bat, one of which has recently become extinct. Free from mammalian competition and predatory threat, birds occupied or dominated all major niches in the New Zealand animal ecology. Moa were grazers — functionally similar to deer or cattle elsewhere — and Haast's Eagle hunters, filling the same niche as top-niche mammalian predators such as tigers or lions.
Classification
DNA analysis has shown that this raptor is most closely related to the much smaller Little Eagle as well as the Booted Eagle (both recently reclassified as belonging to the genus Aquila.[5]) and not, as previously thought, to the large Wedge-tailed Eagle[6] Thus, Harpagornis moorei may be reclassified as Aquila moorei, pending confirmation. H. moorei may have diverged from these smaller eagles as recently as 700,000 to 1.8 million years ago. Its increase in weight by 10 to 15 times over that period is the greatest and fastest evolutionary increase in weight of any known vertebrate. This was made possible in part by the presence of large prey and the absence of competition from other large predators.
Haast's Eagle was first classified by Julius von Haast, who named it Harpagornis moorei after George Henry Moore, the owner of the Glenmark Estate where bones of the bird had been found.
In art
An artwork depicting Haast's Eagle can now be viewed at OceanaGold's Heritage & Art Park at Macraes, Otago, New Zealand. The sculpture weighing in at approximately 750kgs, standing 7.5 metres tall and with a wingspan of 11.5 metres is constructed from stainless steel tube and sheet and was designed and constructed by Mark Hill, a sculptor from Arrowtown, New Zealand. [7]
See also
References
- ^ Miskelly, C. M. (1987): The identity of the hakawai. Notornis 34(2): 95-116. PDF fulltext
- ^ a b Brathwaite, D. H. (1992): Notes on the weight, flying ability, habitat, and prey of Haast's Eagle (Harpagornis moorei). Notornis 39(4): 239–247. PDF fulltext
- ^ Tennyson, A. & Martinson, P. (2006): Extinct Birds of New Zealand; Te Papa Press, Wellington, New Zealand, ISBN 978-0-909010-21-8
- ^ Worthy, T. H. and R. N. Holdaway. (2002): The lost world of the Moa: Prehistoric Life of New Zealand. Indiana University Press, Bloomington. ISBN 0-253-34034-9
- ^ Lerner, H. R. L. 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. PDF document
- ^ Bunce, M., et al. (2005): Ancient DNA Provides New Insights into the Evolutionary History of New Zealand's Extinct Giant Eagle. PLoS Biol 3(1): e9 DOI: 10.1371/journal.pbio.0030009 HTML open-access article
- ^ http://www.3news.co.nz/Video/Giant-art-sculptures-pop-up-in-Otago/tabid/372/articleID/85193/cat/58/Default.aspx#video
External links
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Wikispecies has information related to: Harpagornis moorei |
- Haast's Eagle. Harpagornis moorei. by Paul Martinson. Artwork produced for the book Extinct Birds of New Zealand by Alan Tennyson, Te Papa Press, Wellington, 2006
- New Zealand Birds Limited Haast Eagle page
- New Zealand Eagle website
- NZ Conservation Trust (Charles Douglas' reputed sighting)
- Model of Haast's Eagle in the collection of the Museum of New Zealand Te Papa Tongarewa
