Download Buteo galapagoensis, Galapagos Hawk

The IUCN Red List of Threatened Species™
ISSN 2307-8235 (online)
IUCN 2008: T22695909A93533926
Scope: Global
Language: English
Buteo galapagoensis, Galapagos Hawk
Assessment by: BirdLife International
View on www.iucnredlist.org
Citation: BirdLife International. 2016. Buteo galapagoensis. The IUCN Red List of Threatened Species
2016: e.T22695909A93533926. http://dx.doi.org/10.2305/IUCN.UK.20163.RLTS.T22695909A93533926.en
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THE IUCN RED LIST OF THREATENED SPECIES™
Taxonomy
Kingdom
Phylum
Class
Order
Family
Animalia
Chordata
Aves
Accipitriformes
Accipitridae
Taxon Name: Buteo galapagoensis (Gould, 1837)
Common Name(s):
• English:
• Spanish:
Galapagos Hawk, Galápagos Hawk
Busardo de Galápagos, Gavilán de Galapagos
Taxonomic Source(s):
del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A. and Fishpool, L.D.C. 2014. HBW and BirdLife
International Illustrated Checklist of the Birds of the World. Lynx Edicions BirdLife International,
Barcelona, Spain and Cambridge, UK.
Identification Information:
55 cm. Large, dark hawk. Adult sooty-brown. Grey tail with narrow black bars. Immature browner with
extensive white and buff mottling.
Assessment Information
Red List Category & Criteria:
Vulnerable D1 ver 3.1
Year Published:
2016
Date Assessed:
October 1, 2016
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.
Previously Published Red List Assessments
2012 – Vulnerable (VU) – http://dx.doi.org/10.2305/IUCN.UK.2012-1.RLTS.T22695909A37899125.en
2008 – Vulnerable (VU)
2006 – Vulnerable (VU)
2004 – Vulnerable (VU)
2000 – Vulnerable (VU)
1996 – Vulnerable (VU)
1994 – Vulnerable (VU)
1988 – Threatened (T)
© The IUCN Red List of Threatened Species: Buteo galapagoensis – published in 2016.
http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T22695909A93533926.en
1
Geographic Range
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 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).
Country Occurrence:
Native: Ecuador (Galápagos)
© The IUCN Red List of Threatened Species: Buteo galapagoensis – published in 2016.
http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T22695909A93533926.en
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Distribution Map
Buteo galapagoensis
© The IUCN Red List of Threatened Species: Buteo galapagoensis – published in 2016.
http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T22695909A93533926.en
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Population
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.
Current Population Trend: Stable
Habitat and Ecology (see Appendix for additional information)
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).
Systems: Terrestrial, Marine
Threats (see Appendix for additional information)
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 (see Appendix for additional information)
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
© The IUCN Red List of Threatened Species: Buteo galapagoensis – published in 2016.
http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T22695909A93533926.en
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Monitor the population. Minimise illegal persecution.
Credits
Assessor(s):
BirdLife International
Reviewer(s):
Butchart, S. & Symes, A.
Contributor(s):
Cruz, F., Vargas, H., Wiedenfeld, D. & de Vries, T.
Facilitators(s) and
Compiler(s):
Benstead, P., Isherwood, I., McClellan, R., Sharpe, C J, Symes, A., Derhé, M.
© The IUCN Red List of Threatened Species: Buteo galapagoensis – published in 2016.
http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T22695909A93533926.en
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Bibliography
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.
IUCN. 2016. The IUCN Red List of Threatened Species. Version 2016-3. Available at: www.iucnredlist.org.
(Accessed: 07 December 2016).
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.
Wiedenfeld, D. A.; Jiménez-Uzcátegui, G. A. 2008. Critical problems for bird conservation in the
Galápagos Islands. Cotinga: 22-27.
Citation
BirdLife International. 2016. Buteo galapagoensis. The IUCN Red List of Threatened Species 2016:
e.T22695909A93533926. http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T22695909A93533926.en
Disclaimer
To make use of this information, please check the Terms of Use.
External Resources
For Images and External Links to Additional Information, please see the Red List website.
© The IUCN Red List of Threatened Species: Buteo galapagoensis – published in 2016.
http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T22695909A93533926.en
6
Appendix
Habitats
(http://www.iucnredlist.org/technical-documents/classification-schemes)
Habitat
Season
Suitability
Major
Importance?
1. Forest -> 1.5. Forest - Subtropical/Tropical Dry
Resident
Suitable
No
3. Shrubland -> 3.5. Shrubland - Subtropical/Tropical Dry
Resident
Suitable
No
12. Marine Intertidal -> 12.1. Marine Intertidal - Rocky Shoreline
Resident
Suitable
No
12. Marine Intertidal -> 12.6. Marine Intertidal - Tidepools
Resident
Suitable
No
Threats
(http://www.iucnredlist.org/technical-documents/classification-schemes)
Threat
Timing
Scope
Severity
Impact Score
5. Biological resource use -> 5.1. Hunting & trapping
terrestrial animals -> 5.1.1. Intentional use (species is
the target)
Past,
unlikely to
return
Majority (5090%)
Slow, significant
declines
Past impact
Stresses:
2. Species Stresses -> 2.1. Species mortality
Ongoing
Minority (50%)
Stresses:
2. Species Stresses -> 2.1. Species mortality
Ongoing
Minority (50%)
Stresses:
2. Species Stresses -> 2.3. Indirect species effects ->
2.3.2. Competition
5. Biological resource use -> 5.1. Hunting & trapping
terrestrial animals -> 5.1.3. Persecution/control
8. Invasive and other problematic species, genes &
diseases -> 8.1. Invasive non-native/alien
species/diseases -> 8.1.2. Named species (Felis catus)
Negligible declines
No decline
Low impact: 4
Low impact: 4
Conservation Actions in Place
(http://www.iucnredlist.org/technical-documents/classification-schemes)
Conservation Actions in Place
In-Place Research, Monitoring and Planning
Action Recovery plan: No
Systematic monitoring scheme: No
In-Place Land/Water Protection and Management
Conservation sites identified: Yes, over entire range
Occur in at least one PA: Yes
Invasive species control or prevention: No
© The IUCN Red List of Threatened Species: Buteo galapagoensis – published in 2016.
http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T22695909A93533926.en
7
Conservation Actions in Place
In-Place Species Management
Successfully reintroduced or introduced beningly: No
Subject to ex-situ conservation: No
In-Place Education
Subject to recent education and awareness programmes: No
Included in international legislation: No
Subject to any international management/trade controls: Yes
Conservation Actions Needed
(http://www.iucnredlist.org/technical-documents/classification-schemes)
Conservation Actions Needed
5. Law & policy -> 5.1. Legislation -> 5.1.3. Sub-national level
Research Needed
(http://www.iucnredlist.org/technical-documents/classification-schemes)
Research Needed
3. Monitoring -> 3.1. Population trends
Additional Data Fields
Distribution
Continuing decline in area of occupancy (AOO): Unknown
Extreme fluctuations in area of occupancy (AOO): No
Estimated extent of occurrence (EOO) (km²): 29600
Continuing decline in extent of occurrence (EOO): Unknown
Extreme fluctuations in extent of occurrence (EOO): No
Number of Locations: 6-10
Continuing decline in number of locations: Unknown
Extreme fluctuations in the number of locations: No
Upper elevation limit (m): 1700
Population
Number of mature individuals: 270-330
© The IUCN Red List of Threatened Species: Buteo galapagoensis – published in 2016.
http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T22695909A93533926.en
8
Population
Continuing decline of mature individuals: Unknown
Extreme fluctuations: No
Population severely fragmented: No
No. of subpopulations: 9
Continuing decline in subpopulations: Unknown
Extreme fluctuations in subpopulations: No
All individuals in one subpopulation: No
No. of individuals in largest subpopulation: 1-89
Habitats and Ecology
Continuing decline in area, extent and/or quality of habitat: Unknown
Generation Length (years): 9.7
Movement patterns: Not a Migrant
© The IUCN Red List of Threatened Species: Buteo galapagoensis – published in 2016.
http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T22695909A93533926.en
9
The IUCN Red List Partnership
The IUCN Red List of Threatened Species™ is produced and managed by the IUCN Global Species
Programme, the IUCN Species Survival Commission (SSC) and The IUCN Red List Partnership.
The IUCN Red List Partners are: Arizona State University; BirdLife International; Botanic Gardens
Conservation International; Conservation International; NatureServe; Royal Botanic Gardens, Kew;
Sapienza University of Rome; Texas A&M University; and Zoological Society of London.
THE IUCN RED LIST OF THREATENED SPECIES™