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Galapagos Hawk Buteo galapagoensis

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.

Taxonomic source(s)
SACC. 2006. A classification of the bird species of South America. Available at: http://www.museum.lsu.edu/~Remsen/SACCBaseline.html.
Sibley, C. G.; Monroe, B. L. 1990. Distribution and taxonomy of birds of the world. Yale University Press, New Haven, USA.
Stotz, D. F.; Fitzpatrick, J. W.; Parker, T. A.; Moskovits, D. K. 1996. Neotropical birds: ecology and conservation. University of Chicago Press, Chicago.

Identification
55 cm. Large, dark hawk. Adult sooty-brown. Grey tail with narrow black bars. Immature browner with extensive white and buff mottling.

Distribution and population
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 1970s (de Vries 1973). 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) (de Vries 1973). Recent records of single birds on Santa Cruz are presumed to be stragglers from other islands (T. de Vries in litt. 2000, 2007), although the possibility of there being a very small population there has not been ruled out (D. Wiedenfeld in litt. 2012). 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 individuals (Faaborg 1984). The total population may number 400-500 adults and 300-400 juveniles (T. de Vries in litt. 2000, 2007).

Population justification
The population is estimated to number 400-500 individuals, roughly equivalent to 270-330 mature individuals (T. de Vries in litt. 2000).

Trend justification
The population is thought to be stable although the very small breeding range of the species renders it susceptible to human persecution and predation by invasive species.

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 tree (Thiollay 1994). 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 chicks (Faaborg et al. 1995). Genetic research indicates there is little movement between island populations (Bollmer et al. 2005).


Threats
The most probable cause of the species's historical decline is persecution by humans (de Vries 1973), which still continues on Santa Cruz and south Isabela (H. Vargas and F. Cruz in litt. 2000) but is now a fairly uncommon practice elsewhere (D. Wiedenfeld in litt. 2012). The largest island, Isabela, may support a comparatively small population owing to competition for food with introduced feral cats and other predators (de Vries 1973). Similar scenarios may have been partly responsible for the local extinctions. Lack of genetic diversity (Bollmer et al. 2005) has been suggested as a potential threat, and it has led to increased parasite loads and vulnerability to disease in certain island populations (Whiteman et al. 2006), but the species has never had a large effective population size so this is unlikely to become a major threat to the species now (D. Wiedenfeld in litt. 2007). The removal of goats and pigs from Santiago may reduce habitat for non-breeding individuals as vegetation recovers (T. de Vries in litt. 2000, 2007).


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 1959 (de Vries 1973). The possibility of reintroduction to previously inhabited islands has been discussed (de Vries 1984, Faaborg 1984), but advised against as prey-supply may have declined, and the effects may be detrimental to other threatened species (de Vries 1984). Ecological research is ongoing and will result in detailed information on each island population (T. de Vries in litt. 2000, 2007). A study on natal dispersal collected from 1998 to 2009 from a banded population of 25 territorial groups (Rivera et al. 2011). Rats were eradicated from Rábida, Bartolomé and Bainbridge #3 islands in 2011.
Conservation Actions Proposed
Monitor the population. Minimise illegal persecution.

References
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.

Rivera, J. L., Vargas, H. and Parker, P. 2011. Natal Dispersal and Sociality of Young Galapagos Hawks on Santiago Island. The Open Ornithology Journal 4: 12-16.

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.

Text account compilers
Benstead, P., Isherwood, I., McClellan, R., Sharpe, C J, Symes, A., Derhé, M.

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

IUCN Red List evaluators
Butchart, S., Symes, A.

Recommended citation
BirdLife International (2014) Species factsheet: Buteo galapagoensis. Downloaded from http://www.birdlife.org on 24/04/2014. Recommended citation for factsheets for more than one species: BirdLife International (2014) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 24/04/2014.

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

To provide new information to update this factsheet or to correct any errors, please email BirdLife

To contribute to discussions on the evaluation of the IUCN Red List status of Globally Threatened Birds, please visit BirdLife's Globally Threatened Bird Forums.

Additional resources for this species

ARKive species - Galapagos hawk (Buteo galapagoensis) 0

Key facts
Current IUCN Red List category Vulnerable
Family Accipitridae (Osprey, kites, hawks and eagles)
Species name author (Gould, 1837)
Population size 270-330 mature individuals
Population trend Stable
Distribution size (breeding/resident) 5,700 km2
Country endemic? Yes
Links to further information
- Additional Information on this species