Download Geospiza pauper, Medium Tree-finch

The IUCN Red List of Threatened Species™
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IUCN 2008: T22723773A94832138
Scope: Global
Language: English
Geospiza pauper, Medium Tree-finch
Assessment by: BirdLife International
View on www.iucnredlist.org
Citation: BirdLife International. 2016. Geospiza pauper. The IUCN Red List of Threatened Species
2016: e.T22723773A94832138. http://dx.doi.org/10.2305/IUCN.UK.20163.RLTS.T22723773A94832138.en
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THE IUCN RED LIST OF THREATENED SPECIES™
Taxonomy
Kingdom
Phylum
Class
Order
Family
Animalia
Chordata
Aves
Passeriformes
Thraupidae
Taxon Name: Geospiza pauper (Ridgway, 1890)
Synonym(s):
• Camarhynchus pauper Ridgway, 1890
Common Name(s):
• English:
Medium Tree-finch
Taxonomic Source(s):
del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A., Fishpool, L.D.C., Boesman, P. and Kirwan, G.M. 2016.
HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 2: Passerines. Lynx
Edicions and BirdLife International, Barcelona, Spain and Cambridge, UK.
Identification Information:
12.5 cm. Chunky finch. Male has black head, greyish-brown upperparts, and whitish or yellowish
underparts. Female has greyish-brown head. Similar spp. Differs from Large Tree-finch C. psittacula
mainly in substantially smaller and less parrot-like bill, and from Small Tree-finch C. parvulus in larger
bill. Voice Five-syllable series of tju notes or a dzi-dzi-dzi.
Assessment Information
Red List Category & Criteria:
Critically Endangered B1ab(v) ver 3.1
Year Published:
2016
Date Assessed:
October 1, 2016
Justification:
This species qualifies as Critically Endangered as it has a very small range on a single island, and recent
information suggests that it is declining rapidly owing to the effects of the dipterid parasite Philornis
downsi.
Previously Published Red List Assessments
2015 – Critically Endangered (CR) – http://dx.doi.org/10.2305/IUCN.UK.20154.RLTS.T22723773A77657003.en
2013 – Critically Endangered (CR) – http://dx.doi.org/10.2305/IUCN.UK.20132.RLTS.T22723773A49532348.en
2012 – Critically Endangered (CR)
2010 – Critically Endangered (CR)
2009 – Critically Endangered (CR)
© The IUCN Red List of Threatened Species: Geospiza pauper – published in 2016.
http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T22723773A94832138.en
1
2008 – Vulnerable (VU)
2004 – Vulnerable (VU)
2000 – Vulnerable (VU)
1994 – Lower Risk/near threatened (LR/nt)
1988 – Threatened (T)
Geographic Range
Range Description:
Camarhynchus pauper is endemic to Floreana Island in the Galápagos Islands, Ecuador, where it has a
small to moderate population in the highlands, and is uncommon to rare on the coast (Harris 1982, H.
Vargas and F. Cruz in litt. 2000, J. O'Connor in litt. 2010). Recent estimates put the total population at
not more than 1,660 individuals, and it has recently begun declining rapidly owing to the effects of the
introduced dipterid parasite Philornis downsi (O'Connor et al. 2010a, 2010b). Its largest population can
be found around the base of the volcano Cerro Pajas, where its preferred nesting tree Scalesia
pedunculata is dominant (O'Connor et al. 2010a).
Country Occurrence:
Native: Ecuador (Galápagos)
© The IUCN Red List of Threatened Species: Geospiza pauper – published in 2016.
http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T22723773A94832138.en
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Distribution Map
Geospiza pauper
© The IUCN Red List of Threatened Species: Geospiza pauper – published in 2016.
http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T22723773A94832138.en
3
Population
The maximum size of the population was estimated at 1,660 individuals in 2008. It is best placed in the
band 1,000-2,499 individuals, equating to 667-1,666 mature individuals, rounded here to 600-1,700
mature individuals.
Trend Justification
Numbers in 2008 were 39% of those recorded in 2004, indicating a decline outside the range expected
for a fluctuating but stable population. Density fell from 154 birds/km2 in 2004 to 60 birds/km2 in 2008
at Cerro Pajas, and it is significantly less common now than it was 50 to 100 years ago (O'Connor et al. in
prep.)
Current Population Trend: Decreasing
Habitat and Ecology (see Appendix for additional information)
It inhabits montane evergreen and tropical deciduous forest, and Scalesia-zone humid scrub (Stotz et al.
1996) mainly at elevations of 300-400 m (O'Connor et al. 2010a). It feeds on insects, nectar, young buds
and leaves, probing crevices in the bark of trees and searching under twigs and foliage (Castro and
Phillips 1996).
Systems: Terrestrial
Threats (see Appendix for additional information)
The most significant threat is from the introduced ectoparasite Philornis downsi, which occurs in finch
nests on Floreana (Wiedenfeld et al. 2007), and is responsible for 41% of nestling mortality (O'Connor et
al. 2010a, S. Kleindorfer in litt. 2008). In 2004-2008 nesting success was extremely low in all years (4-8 %
of all nests producing fledglings), 28% of nestlings were predated, and parasite intensity from P. downsi
was second highest of any bird species studied so far on the Galápagos archipelago (O'Connor et al.
2010a). It is thought to be at elevated risk from fly parasitism because its only extant habitat is adjacent
to cleared agricultural land with fruiting trees which are favoured by the adult fly (S. Kleindorfer in litt.
2008). Floreana has a suite of introduced predators and herbivores including cattle, donkeys, pigs, cats,
dogs and rats (Jackson 1985), and suffers from extensive habitat destruction and degradation as a result
of agriculture (Cruz and Cruz 1996), habitat alteration by invasive plant species, and free-ranging
domestic livestock (H. Vargas and F. Cruz in litt. 2000). Avian pox (Avipox virus) occurs on the island and
infects a significant proportion of individuals. Predator marks from invasive rodents increased threefold
between 2004-2008, and tourist visitation to favoured Scalesia habitat has increased more than tenfold
since 2004 (S. Kleindorfer in litt. 2008). Having a montane distribution that is close to the maximum
altitude within its range, this species is potentially susceptible to climate change (BirdLife International
unpublished data). The species also appears to be at risk from hybridization with Camarhynchus
psittacula and Camarhynchus parvulus, which may have already resulted in the local extinction of C.
psittacula on Floreana (Kleindorfer et al. 2014).
Conservation Actions (see Appendix for additional information)
Conservation and Research Actions Underway
The Galápagos National Park was gazetted in 1959, and includes almost all the land area of the islands.
Although the park incorporates most of Floreana, it does not include the agricultural zone of the island,
© The IUCN Red List of Threatened Species: Geospiza pauper – published in 2016.
http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T22723773A94832138.en
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an area which was the prime habitat for Medium Tree-finch. In 1979, the islands were declared a World
Heritage Site (Jackson 1985). In December 2006, the Galápagos National Park began the eradication of
goats and donkeys on Floreana which successful reduced their population to negligible numbers (J.
O'Connor in litt. 2010). The Galápagos National Park places rat baiting stations around the Critically
Endangered Galápagos Petrel breeding colony in the centre of Cerro Pajas, which may also reduce nest
predation of Medium Tree-Finches in the immediate area (J. O'Connor in litt. 2010). Methods to control
or eradicate Philornis downsi are currently being trialled by researchers and visiting scientists at the
Charles Darwin Research Station (J. O'Connor in litt. 2010).
Conservation and Research Actions Proposed
Investigate methods to control or eradicate Philornis downsi. Continue to monitor the population size.
Extend the national park to incorporate the agricultural zone on Floreana. Continue and extend control
measures against introduced species.
Credits
Assessor(s):
BirdLife International
Reviewer(s):
Butchart, S. & Symes, A.
Contributor(s):
Cruz, F., Kleindorfer, S., O'Connor, J., Vargas, H. & Wiedenfeld, D.
Facilitators(s) and
Compiler(s):
Isherwood, I., McClellan, R., Pople, R., Sharpe, C J, Symes, A., Khwaja, N. & Wright,
L
© The IUCN Red List of Threatened Species: Geospiza pauper – published in 2016.
http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T22723773A94832138.en
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Bibliography
Castro, I.; Phillips, A. 1996. A guide to the birds of the Galápagos Islands. A&C Black, London.
Christensen, R.; Kleindorfer, S. 2009. Jack of all trades or master of one? Variation in foraging
specialisation across years in Darwin's Tree Finches (Camarhynchus spp.). Journal of Ornithology 150(2):
383-391.
Cruz, J. B.; Cruz, F. 1996. Conservation of the Dark-rumped Petrel Pterodroma phaeopygia of the
Galápagos Islands, 1982-1991. Bird Conservation International 6: 23-32.
Grant, P. R.; Grant, B. R.; Petren, K.; Keller, L. F. 2005. Extinction behind our backs: the possible fate of
one of the Darwin’s finch species on Isla Floreana, Galápagos. Biological Conservation 122: 499-503.
Harris, M. P. 1982. A field guide to the birds of Galápagos. Collins, London.
IUCN. 2016. The IUCN Red List of Threatened Species. Version 2016-3. Available at: www.iucnredlist.org.
(Accessed: 07 December 2016).
Jackson, M. H. 1985. Galapagos: a natural history guide. Calgary University Press, Calgary, Canada.
Jaramillo, A. 2014. Medium Tree-finch (Camarhynchus pauper). In: del Hoyo, J., Elliott, A., Sargatal, J.,
Christie, D.A. and de Juana, E. (eds), Handbook of the Birds of the World Alive, Lynx Edicions, Barcelona.
Kleindorfer, S., O’Connor, J.A., Dudaniec, R.Y., Myers, S.A., Robertson, J. and Sulloway, F.J. 2014. Species
Collapse via hybridization in Darwin’s tree finches. The American Naturalist 183(3): 325-341.
O’Connor, J.A., Sulloway, F.J. and Kleindorfer, S. 2010. Avian population survey in the Floreana highlands:
Is Darwin’s medium tree finch declining in remnant patches of Scalesia forest? Bird Conservation
International.
O'Connor, J.A., Sulloway, F.J. and Kleindorfer, S. 2010. Avian population survey in the Floreana highlands:
is Darwin's medium tree finch declining in remnant patches of Scalesia forest? Bird Conservation
International 20(4): 343-353.
O'Connor, J.A., Sulloway, F.J., Robertson, J. and Kleindorfer, S. 2010. Philornis downsi parasitism is the
primary cause of nestling mortality in the critically endangered Darwin's medium tree finch
(Camarhynchus pauper). Biodiversity and Conservation 19(3): 853-866.
Stotz, D. F.; Fitzpatrick, J. W.; Parker, T. A.; Moskovits, D. K. 1996. Neotropical birds: ecology and
conservation. University of Chicago Press, Chicago.
Wiedenfeld, D. A.; Jiménez, G. A.; Fessl, B.; Kleindorfer, S.; Valerezo, J. C. 2007. Distribution of the
introduced parasitic fly Philornis downsi (Diptera, Muscidae) in the Galapagos Islands. Pacific
Conservation Biology 13: 14-19.
Citation
BirdLife International. 2016. Geospiza pauper. The IUCN Red List of Threatened Species 2016:
e.T22723773A94832138. http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T22723773A94832138.en
Disclaimer
To make use of this information, please check the Terms of Use.
© The IUCN Red List of Threatened Species: Geospiza pauper – published in 2016.
http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T22723773A94832138.en
6
External Resources
For Images and External Links to Additional Information, please see the Red List website.
© The IUCN Red List of Threatened Species: Geospiza pauper – published in 2016.
http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T22723773A94832138.en
7
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
Yes
1. Forest -> 1.9. Forest - Subtropical/Tropical Moist Montane
Resident
Suitable
Yes
3. Shrubland -> 3.6. Shrubland - Subtropical/Tropical Moist
Resident
Suitable
Yes
Threats
(http://www.iucnredlist.org/technical-documents/classification-schemes)
Threat
Timing
Scope
Severity
Impact Score
11. Climate change & severe weather -> 11.1. Habitat
shifting & alteration
Future
Whole (>90%)
Unknown
Unknown
Stresses:
1. Ecosystem stresses -> 1.2. Ecosystem degradation
1. Ecosystem stresses -> 1.3. Indirect ecosystem effects
Ongoing
Majority (5090%)
Stresses:
1. Ecosystem stresses -> 1.1. Ecosystem conversion
1. Ecosystem stresses -> 1.2. Ecosystem degradation
Ongoing
Majority (5090%)
Stresses:
1. Ecosystem stresses -> 1.2. Ecosystem degradation
Ongoing
Majority (5090%)
Stresses:
1. Ecosystem stresses -> 1.2. Ecosystem degradation
Ongoing
Majority (5090%)
Stresses:
2. Species Stresses -> 2.1. Species mortality
2. Species Stresses -> 2.3. Indirect species effects ->
2.3.7. Reduced reproductive success
Ongoing
Majority (5090%)
Stresses:
2. Species Stresses -> 2.1. Species mortality
2. Agriculture & aquaculture -> 2.1. Annual &
perennial non-timber crops -> 2.1.2. Small-holder
farming
8. Invasive and other problematic species, genes &
diseases -> 8.1. Invasive non-native/alien
species/diseases -> 8.1.1. Unspecified species
8. Invasive and other problematic species, genes &
diseases -> 8.1. Invasive non-native/alien
species/diseases -> 8.1.2. Named species (Bos
taurus)
8. Invasive and other problematic species, genes &
diseases -> 8.1. Invasive non-native/alien
species/diseases -> 8.1.2. Named species (Philornis
downsi)
8. Invasive and other problematic species, genes &
diseases -> 8.1. Invasive non-native/alien
species/diseases -> 8.1.2. Named species (Felis catus)
© The IUCN Red List of Threatened Species: Geospiza pauper – published in 2016.
http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T22723773A94832138.en
Unknown
Unknown
Unknown
Rapid declines
Unknown
Unknown
Unknown
Unknown
Medium
impact: 7
Unknown
8
8. Invasive and other problematic species, genes &
diseases -> 8.1. Invasive non-native/alien
species/diseases -> 8.1.2. Named species (Sus
domesticus)
8. Invasive and other problematic species, genes &
diseases -> 8.1. Invasive non-native/alien
species/diseases -> 8.1.2. Named species (Canis
familiaris)
8. Invasive and other problematic species, genes &
diseases -> 8.1. Invasive non-native/alien
species/diseases -> 8.1.2. Named species (Equus
asinus)
8. Invasive and other problematic species, genes &
diseases -> 8.1. Invasive non-native/alien
species/diseases -> 8.1.2. Named species (Rattus
rattus)
8. Invasive and other problematic species, genes &
diseases -> 8.2. Problematic native species/diseases
-> 8.2.2. Named species (Geospiza psittacula)
8. Invasive and other problematic species, genes &
diseases -> 8.2. Problematic native species/diseases
-> 8.2.2. Named species (Geospiza parvula)
8. Invasive and other problematic species, genes &
diseases -> 8.5. Viral/prion-induced diseases -> 8.5.2.
Named species
Ongoing
Majority (5090%)
Unknown
Stresses:
1. Ecosystem stresses -> 1.2. Ecosystem degradation
Ongoing
Majority (5090%)
Stresses:
2. Species Stresses -> 2.1. Species mortality
Ongoing
Majority (5090%)
Stresses:
1. Ecosystem stresses -> 1.2. Ecosystem degradation
Ongoing
Majority (5090%)
Stresses:
2. Species Stresses -> 2.1. Species mortality
2. Species Stresses -> 2.3. Indirect species effects ->
2.3.7. Reduced reproductive success
Ongoing
Whole (>90%)
Stresses:
2. Species Stresses -> 2.3. Indirect species effects ->
2.3.1. Hybridisation
Ongoing
Whole (>90%)
Stresses:
2. Species Stresses -> 2.3. Indirect species effects ->
2.3.1. Hybridisation
Ongoing
Majority (5090%)
Stresses:
2. Species Stresses -> 2.1. Species mortality
2. Species Stresses -> 2.3. Indirect species effects ->
2.3.7. Reduced reproductive success
Unknown
Unknown
Unknown
Unknown
Unknown
Rapid declines
Unknown
Unknown
Unknown
Unknown
Unknown
Unknown
Medium
impact: 7
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
© The IUCN Red List of Threatened Species: Geospiza pauper – published in 2016.
http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T22723773A94832138.en
9
Conservation Actions in Place
Conservation sites identified: Yes, over entire range
Occur in at least one PA: Yes
Invasive species control or prevention: No
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: No
Conservation Actions Needed
(http://www.iucnredlist.org/technical-documents/classification-schemes)
Conservation Actions Needed
1. Land/water protection -> 1.1. Site/area protection
2. Land/water management -> 2.2. Invasive/problematic species control
Research Needed
(http://www.iucnredlist.org/technical-documents/classification-schemes)
Research Needed
1. Research -> 1.5. Threats
3. Monitoring -> 3.1. Population trends
Additional Data Fields
Distribution
Estimated area of occupancy (AOO) (km²): 23
Continuing decline in area of occupancy (AOO): Unknown
Extreme fluctuations in area of occupancy (AOO): No
Estimated extent of occurrence (EOO) (km²): 30
Continuing decline in extent of occurrence (EOO): Unknown
Extreme fluctuations in extent of occurrence (EOO): No
© The IUCN Red List of Threatened Species: Geospiza pauper – published in 2016.
http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T22723773A94832138.en
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Distribution
Number of Locations: 1
Continuing decline in number of locations: Unknown
Extreme fluctuations in the number of locations: No
Lower elevation limit (m): 0
Upper elevation limit (m): 640
Population
Number of mature individuals: 600-1700
Continuing decline of mature individuals: Yes
Extreme fluctuations: No
Population severely fragmented: No
No. of subpopulations: 1
Continuing decline in subpopulations: Unknown
Extreme fluctuations in subpopulations: No
All individuals in one subpopulation: Yes
No. of individuals in largest subpopulation: 100
Habitats and Ecology
Continuing decline in area, extent and/or quality of habitat: Unknown
Generation Length (years): 3.80
Movement patterns: Not a Migrant
© The IUCN Red List of Threatened Species: Geospiza pauper – published in 2016.
http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T22723773A94832138.en
11
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™