Buteo galapagoensis

Taxonomy

Assessment Information

Geographic Range

Population

Habitat and Ecology

Threats

Conservation Actions

Bibliography

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Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
ANIMALIA	CHORDATA	AVES	FALCONIFORMES	ACCIPITRIDAE

Scientific Name:

Buteo galapagoensis

Species Authority:

(Gould, 1837)

Common Name/s:

English	–	Galapagos Hawk, Galápagos Hawk
Spanish	–	Busardo de Galápagos, Gavilán de Galapagos

Assessment Information [top]

Red List Category & Criteria:

Vulnerable D1 ver 3.1

Year Published:

2008

Assessor/s:

BirdLife International

Reviewer/s:

Symes, A., Butchart, S.

Contributor/s:

Wiedenfeld, D., Cruz, F., de Vries, T., Vargas, H.

Justification:
This species is listed as Vulnerable because it has a small population. Trends are not clear, but are assumed to be stable. If threats, notably persecution, were shown to be causing a decline, this species would warrant uplisting to Endangered.

History:

2006	–	Vulnerable
2004	–	Vulnerable
2000	–	Vulnerable
1996	–	Vulnerable
1994	–	Vulnerable

Geographic Range [top]

Range Description:	Buteo galapagoensis was apparently once common on most of the main islands of the Galápagos, Ecuador. The population is difficult to measure except in terms of breeding territories, of which 130 were estimated in the early 1970s⁵. Following a serious population decline, it is now extinct on five islands, and present on Santiago (c.50 territories), Española (10), Isabela (c.25), Fernandina (10), Pinta (12-15), Marchena (5), Pinzón (5) and Santa Fe (17)⁵. Recent records of single birds on Santa Cruz are presumed to be stragglers from other islands⁷. The breeding system means that the population is larger than the number of territories suggests, for example, the population on Santiago may number 180 adults in the 50 territories, with a total of c.250 individuals¹. The total population may number 400-500 adults and 300-400 juveniles⁷.
Countries:	Native: Ecuador
Range Map:	Click here to open the map viewer and explore range.

Population [top]

Population:	T. de Vries in litt. (2000)
Population Trend:	Stable

Habitat and Ecology [top]

Habitat and Ecology:	It is found in all habitats, from shoreline to bare lava-fields, open, rocky, scrub country, deciduous forests and mountain peaks. It feeds on a wide variety of sea and landbirds, rats, lizards, iguanas, invertebrates and carrion. It breeds throughout the year. It nests on a stick platform on a prominent lava outflow, rocky outcrop or in a small tree³. It is cooperatively polyandrous, with one female typically mating with two or three males (up to eight males have been recorded), and all males helping in raising the chicks². Genetic research indicates there is little movement between island populations⁹.
Systems:	Terrestrial; Marine

Habitat and Ecology:

It is found in all habitats, from shoreline to bare lava-fields, open, rocky, scrub country, deciduous forests and mountain peaks. It feeds on a wide variety of sea and landbirds, rats, lizards, iguanas, invertebrates and carrion. It breeds throughout the year. It nests on a stick platform on a prominent lava outflow, rocky outcrop or in a small tree³. It is cooperatively polyandrous, with one female typically mating with two or three males (up to eight males have been recorded), and all males helping in raising the chicks². Genetic research indicates there is little movement between island populations⁹.

Systems:

Terrestrial; Marine

Threats [top]

Major Threat(s):	The most probable cause of the species's historical decline is persecution by humans⁵, which still continues on Santa Cruz and south Isabela⁴. The largest island, Isabela, may support a comparatively small population owing to competition for food with introduced feral cats and other predators⁵. Similar scenarios may have been partly responsible for the local extinctions. Lack of genetic diversity⁹ has been suggested as a potential threat, and it has led to increased parasite loads and vulnerability to disease in certain island populations⁸, but the species has never had a large effective population size so this is unlikely to become a major threat to the species now¹⁰. The removal of goats and pigs from Santiago may reduce habitat for non-breeding individuals as vegetation recovers⁷.

Major Threat(s):

The most probable cause of the species's historical decline is persecution by humans⁵, which still continues on Santa Cruz and south Isabela⁴. The largest island, Isabela, may support a comparatively small population owing to competition for food with introduced feral cats and other predators⁵. Similar scenarios may have been partly responsible for the local extinctions. Lack of genetic diversity⁹ has been suggested as a potential threat, and it has led to increased parasite loads and vulnerability to disease in certain island populations⁸, but the species has never had a large effective population size so this is unlikely to become a major threat to the species now¹⁰. The removal of goats and pigs from Santiago may reduce habitat for non-breeding individuals as vegetation recovers⁷.

Conservation Actions [top]

Conservation Actions:	Conservation Actions Underway CITES Appendix II. Most of the archipelago is under national park and marine reserve protection and, in 1979, was declared a World Heritage Site. The species has been protected by Ecuadorian law since 1959⁵. The possibility of reintroduction to previously inhabited islands has been discussed^1,6, but advised against as prey-supply may have declined, and the effects may be detrimental to other threatened species⁶. Ecological research is ongoing and will result in detailed information on each island population⁷. Conservation Actions Proposed Monitor the population. Minimise illegal persecution.

Conservation Actions:

Conservation Actions Underway
CITES Appendix II. Most of the archipelago is under national park and marine reserve protection and, in 1979, was declared a World Heritage Site. The species has been protected by Ecuadorian law since 1959⁵. The possibility of reintroduction to previously inhabited islands has been discussed^1,6, but advised against as prey-supply may have declined, and the effects may be detrimental to other threatened species⁶. Ecological research is ongoing and will result in detailed information on each island population⁷.

Conservation Actions Proposed
Monitor the population. Minimise illegal persecution.

Bibliography [top]

	Bollmer, J. L.; Whiteman, N. K.; Cannon, M.D.; Bednarz, J.C.; de Vries, T.; Parker, P. G. 2005. Population genetics of the Galapagos Hawk (Buteo galapagoensis): genetic monomorphism within isolated populations. The Auk 122: 1210-1224. Collar, N. J.; Gonzaga, L. P.; Krabbe, N.; Madroño Nieto, A.; Naranjo, L. G.; Parker, T. A.; Wege, D. C. 1992. Threatened birds of the Americas: the ICBP/IUCN Red Data Book. International Council for Bird Preservation, Cambridge, U.K. de Vries, T. 1973. The Galápagos Hawk: an eco-geographical study with special reference to its systematic position. Thesis. Doctorate, University of Amsterdam. de Vries, T. 1984. Problems of reintroducing native animals on islands where they have been exterminated. Notícias de Galápagos 40: 12. Faaborg, J. 1984. Potential for restocking Galápagos Hawks on islands where they have been extirpated. Notícias de Galápagos 39: 28-30. Faaborg, J.; Parker, P. G.; DeLay, L.; de Vries, T. J.; Bednarz, J. C.; Paz, S. M.; Naranjo, J.; Waite, T. A. 1995. Confirmation of cooperative polyandry in the Galápagos Hawk Buteo galapagoensis. Behavioral Ecology and Sociobiology 36: 83-90. Thiollay, J.-M. 1994. Family Accipitridae (Hawks and Eagles). In: del Hoyo, J.; Elliott, A.; Sargatal, J. (ed.), Handbook of the birds of the world, pp. 52-205. Lynx Edicions, Barcelona, Spain. Whiteman, N. K.; Matson, K.D.; Bollmer, J. L.; Parker, P. G. 2006. Disease ecology in the Galápagos Hawk (Buteo galapagoensis): host genetic diversity, parasite load and natural antibodies. Proceedings of the Royal Society of London Series B 273: 797-804.

Bollmer, J. L.; Whiteman, N. K.; Cannon, M.D.; Bednarz, J.C.; de Vries, T.; Parker, P. G. 2005. Population genetics of the Galapagos Hawk (Buteo galapagoensis): genetic monomorphism within isolated populations. The Auk 122: 1210-1224.

Collar, N. J.; Gonzaga, L. P.; Krabbe, N.; Madroño Nieto, A.; Naranjo, L. G.; Parker, T. A.; Wege, D. C. 1992. Threatened birds of the Americas: the ICBP/IUCN Red Data Book. International Council for Bird Preservation, Cambridge, U.K.

de Vries, T. 1973. The Galápagos Hawk: an eco-geographical study with special reference to its systematic position. Thesis. Doctorate, University of Amsterdam.

de Vries, T. 1984. Problems of reintroducing native animals on islands where they have been exterminated. Notícias de Galápagos 40: 12.

Faaborg, J. 1984. Potential for restocking Galápagos Hawks on islands where they have been extirpated. Notícias de Galápagos 39: 28-30.

Faaborg, J.; Parker, P. G.; DeLay, L.; de Vries, T. J.; Bednarz, J. C.; Paz, S. M.; Naranjo, J.; Waite, T. A. 1995. Confirmation of cooperative polyandry in the Galápagos Hawk Buteo galapagoensis. Behavioral Ecology and Sociobiology 36: 83-90.

Thiollay, J.-M. 1994. Family Accipitridae (Hawks and Eagles). In: del Hoyo, J.; Elliott, A.; Sargatal, J. (ed.), Handbook of the birds of the world, pp. 52-205. Lynx Edicions, Barcelona, Spain.

Whiteman, N. K.; Matson, K.D.; Bollmer, J. L.; Parker, P. G. 2006. Disease ecology in the Galápagos Hawk (Buteo galapagoensis): host genetic diversity, parasite load and natural antibodies. Proceedings of the Royal Society of London Series B 273: 797-804.

Citation:	BirdLife International 2008. Buteo galapagoensis. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. <www.iucnredlist.org>. Downloaded on 21 May 2012.
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