• Summary
• Text account
• Data table and detailed info
• Distribution map
• Reference and further resources

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. Volume 1: Non-passerines. Lynx Edicions BirdLife International, Barcelona, Spain and Cambridge, UK.

Red List criteria met

Critically Endangered	Endangered	Vulnerable
-	-	A2c+3c+4c; C2a(ii)

Red List history

Year	Category	Criteria
2022	Vulnerable	A2c+3c+4c
2016	Vulnerable	C2a(ii)
2012	Vulnerable	C2a(ii)
2008	Vulnerable	C2a(ii)
2006	Vulnerable
2004	Least Concern
2000	Lower Risk/Least Concern
1994	Lower Risk/Near Threatened
1988	Lower Risk/Least Concern

Migratory status	not a migrant	Forest dependency	high
Land-mass type		Average mass	-

	Estimate	Data quality
Extent of Occurrence (breeding/resident)	1,550 km2	medium
Area of Occupancy (breeding/resident)	1,550 km2
Severely fragmented?	no	-

	Estimate	Data quality	Derivation	Year of estimate
Population size	2500-9999 mature individuals	poor	inferred	2006
Population trend	decreasing	poor	inferred	2016-2029
Rate of change over the past 10 years/3 generations (longer of the two periods)	25-30%	-	-	-
Rate of change over the future 10 years/3 generations (longer of the two periods)	25-30%	-	-	-
Rate of change over the past & future 10 years/3 generations (longer of the two periods)	25-30%	-	-	-
Generation length	4.48 years	-	-	-
Number of subpopulations	1	-	-	-
Percentage of mature individuals in largest subpopulation	100%	-	-	-

Population justification: Even with intensive surveying across the island, the species is still relatively 'uncommon' (Catry et al. 2000). More recent visitors to Pemba have struggled to find this species at all, which now appears to be rare (A. Sander in litt. 2004, M. Virani in litt. 2005, J. Wolstencroft in litt. 2005, 2007, N. Burgess in litt. 2012). The population was inferred to be 2,000-3,200 individuals (5-8 individuals/km² x 400 km² [45% of EOO]), based on a density range from the lower and upper quartile of six congeners. This requires validation, and as a result the suspected population size is placed in the band 2,500-9,999 mature individuals. This equates to 3,750-14,999 individuals, rounded here to 3,500-15,000 individuals. However, it has been suggested that the total population may actually number fewer than 500 individuals (J. Wolstencroft in litt. 2007), so further investigation is recommended.

Trend justification: Despite being classed as relatively uncommon in 2000, more recent visitors to Pemba have struggled to find this species at all, which now appears to be rare (A. Sander in litt. 2004, M. Virani in litt. 2005, J. Wolstencroft in litt. 2005, 2007, N. Burgess in litt. 2012), suggesting a decline is ongoing. Tree cover loss within the range is currently estimated at 22% across three generations (13.4 years) (Global Forest Watch 2021, using Hansen et al. [2013] data and methods disclosed therein). As the species is highly forest dependent and does not adapt well to open habitats, population declines are precautionarily suspected to fall between 25-30% over three generations. In particular, loss and degradation of both primary and secondary habitat is occurring (A. Hija in litt. 2005, Virani 2005, M. Virani in litt. 2005, J. Wolstencroft in litt. 2007), with Zanzibar's (Pemba and Unguja) forest declining at 1.2% per year (Siex et al. 2013). This is likely to decrease densities of this species at a slow rate (Catry et al. 2000). There is also a local agricultural trend away from plantation crops and towards open farmland, and if this trend persists, the species could become seriously threatened as it does not seem to be able to adapt well to open farmland habitats (Catry et al. 2000).

Country/Territory	Presence	Origin	Resident	Breeding visitor	Non-breeding visitor	Passage migrant
Tanzania	extant	native	yes

Country/Territory	IBA Name
Tanzania	Pemba Island

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Artificial/Terrestrial	Plantations	suitable	resident
Artificial/Terrestrial	Rural Gardens	suitable	resident
Forest	Subtropical/Tropical Moist Lowland	major	resident
Altitude	0 - 80 m	Occasional altitudinal limits

Threat (level 1)	Threat (level 2)	Impact and Stresses
Agriculture & aquaculture	Annual & perennial non-timber crops - Small-holder farming	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Slow, Significant Declines		Medium Impact: 6
		Stresses Ecosystem degradation, Ecosystem conversion
Agriculture & aquaculture	Wood & pulp plantations - Small-holder plantations	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Slow, Significant Declines		Medium Impact: 6
		Stresses Ecosystem conversion
Biological resource use	Hunting & trapping terrestrial animals - Intentional use (species is the target)	Timing		Scope		Severity		Impact
		Unknown		Unknown		Unknown		Unknown
		Stresses Species mortality
Biological resource use	Logging & wood harvesting - Unintentional effects: (subsistence/small scale) [harvest]	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Slow, Significant Declines		Medium Impact: 6
		Stresses Ecosystem degradation
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Corvus splendens	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Negligible declines		Low Impact: 4
		Stresses Reduced reproductive success
Residential & commercial development	Tourism & recreation areas	Timing		Scope		Severity		Impact
		Future		Minority (<50%)		Slow, Significant Declines		Low Impact: 3
		Stresses Ecosystem degradation, Ecosystem conversion

Purpose	Scale
Food - human	subsistence, national
Sport hunting/specimen collecting	subsistence, national

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Recommended citation
BirdLife International (2024) Species factsheet: Pemba Green-pigeon Treron pembaensis. Downloaded from https://datazone.birdlife.org/species/factsheet/pemba-green-pigeon-treron-pembaensis on 24/11/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from https://datazone.birdlife.org/species/search on 24/11/2024.