Anjouan Island Sparrowhawks

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The Anjouan Island Sparrowhawk (Accipiter francesiae pusillus), also known as Ndzuwani Goshawk or Joanna Island Goshawk is an extremely rare or possible extinct subspecies of the Frances's Sparrowhawk (Accipiter francesiae). It is endemic to the Comoros island of Ndzuwani (Anjouan).


Description

This subspecies looks in both sexes very similar to the male of the nominate race from Madagascar, but are markedly smaller and lack most of the underside barring. The wings have a length between 135 to 149 mm at the males and 155 to 163 mm at the females. The length of the tail reaches from 99 to 188 mm at the males and 113 to 125 mm at the females. It has white underparts, grey upperparts and dark-greyish wings. The tail exhibits a dark barring.


Status

Due to the extensive hunting and habitat loss during the 20th century it became extremely rare by the late 1950s. Only one individual was found in a month-long survey in 1958 and the population was estimated between one and ten birds (Benson 1960). Another expedition in 1965 spent 3 days on Ndzuwani and did not encounter the bird (although no dedicated effort was made to and the key habitat was not visited), but remarked that other subspecies were "extremely tame" (Forbes-Watson 1969), which obviously bodes ill for a frequently-hunted bird.

Apparently, the bird has never been seen by scientists since 1958 (at least not between 1958 and 1977: King 1977-78); it is likely to be extinct today. The last population was found in the mountaineous central uplands. It is somewhat puzzling why this subspecies should have declined so heavily during the first half of the 20th century - it was common in the 1900s (King 1978-79) - while the other Comoros races seem to be able to hold their own (Kemp 1994). Some circumstantial information points at deforestation, especially in the lowlands, due to overpopulation being the main cause for the subspecies' disappearance: A. f. griveaudii of Njazidja (Grande Comore) has declined recently (King 1978-79, Kemp 1994), coincident with a significant population increase, while A. f. brutus is still rather common on Mahoré (Mayotte) where extensive lowland forest remains (Kemp 1994) and population density is around 75% of that on Ndzuwani.

44 specimens were taken up to 1907 (King 1978-79), one of which is on display in the Zoological Museum of the University of Zurich, Switzerland.


References

  • Benson, Constantine Walter (1960): The birds of the Comoro Islands: results of the British Ornithologists' Union centenary expedition. Ibis 103: 5-106.
  • Ferguson-Lees, James and Christie, David A. (2001): Raptors of the World. Houghton Mifflin, Boston. ISBN 0618127623
  • Kemp, Alan C. (1994): 104. Frances's Sparrowhawk. In: del Hoyo, Josep; Elliott, Andrew and Sargatal, Jordi (editors): Handbook of Birds of the World, Volume 2: New World Vultures to Guineafowl: 149, plate 11. Lynx Edicions, Barcelona. ISBN 84-87334-15-6
  • King, W.B. (1978-1979): Red Data Book 2: Aves (2nd edition). IUCN, Morges, Switzerland.

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