• 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
-	D	D1+2

Red List history

Year	Category	Criteria
2024	Endangered	D
2016	Critically Endangered	C2a(ii)
2012	Critically Endangered	C2a(ii)
2009	Critically Endangered	C2a(ii)
2008	Critically Endangered
2004	Critically Endangered
2000	Critically Endangered
1996	Critically Endangered
1994	Critically Endangered
1988	Threatened

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

	Estimate	Data quality
Extent of Occurrence (breeding/resident)	600 km2	medium
Area of Occupancy (breeding/resident)	330 km2
Number of locations	1-5	-
Severely fragmented?	no	-

	Estimate	Data quality	Derivation	Year of estimate
Population size	75-400, 100-300 mature individuals	good	estimated	2023
Population trend	stable	poor	suspected	-
Generation length	4.73 years	-	-	-
Number of subpopulations	1	-	-	-
Percentage of mature individuals in largest subpopulation	100%	-	-	-

Population justification: The population size of this species has not recently been robustly estimated. BirdLife International (2001) estimated a population of 150–584 individuals, but only 75 mature individuals. Since this estimate, the range of this species has expanded more widely across Okinawa in response to active management of invasive mongoose (Yaghihashi et al. 2021) and localised forest regeneration (see Figure 2: Kotaka et al. 2021). In 2013 and 2016 respectively, this species was detected at 104 and 100 of 244 observation points, an increase on the 67 counted in 2007; the total number of birds observed across surveyed squares in 2010, 2013 and 2016 varied between 149–183 (Yagihashi et al. 2021). Two opposing considerations should be made when converting this into a population estimate of mature individuals: (1) not every bird will have been detected, despite the use of playback, thus these numbers should be considered absolute minimum values; but (2) not all birds will have been mature individuals. Accounting for these margins of error, these data suggest a total population of 75–200 mature individuals.

An alternative method of estimation is derived using nesting data from Kotaka et al. (2021), who found between 2017 and 2019 between 1–1.5 nests [= 2 mature individuals] per km², albeit their sample size in each year was very small and not necessarily representative. In its occupied range there is approximately 200 km² of suitable habitat (i.e. closed-canopy forest) not all of which, however, is likely to be occupied. Nonetheless, occupancy is likely high (Yagihashi et al. 2021, eBird 2024) and these data suggest a slightly higher population size of up to c.400 mature individuals.

Combining methods, a population size of 75–400 mature individuals is estimated, with a precautionary best estimate of 100–300.

Trend justification: Trend not well understood, but currently suspected to be stable following concerted conservation effort to create a mongoose-free area on Okinawa, and also protect a large area of this species' range as a national park.

Dendrocopos noguchii was already rare by 1928, with Kobayashi (1930) already commenting then that the species was in danger of extinction. It has remained rare, with the principal cause of its depleted population the widespread clearance of habitat throughout the 20th century (BirdLife International 2001) but there is increasing evidence that the species is negatively associated with the presence of the invasive Small Indian Mongoose Urva auropunctata (see Kotaka 2014), introduced to Okinawa in 1910 (Kishida 1931). Accordingly it has more recently undoubtedly benefited from concerted conservation effort to create a 'mongoose-free' area on the north of the island (Yagihashi et al. 2021, N. Kotaka in litt. 2024).

Repeat-effort playback surveys 2007-2016 recorded the following number (# of occupied squares out of 244, # of birds): 2007 (67, 120), 2010 (96, 165), 2013 (104, 183), 2016 (100, 149) (Yagihashi et al. 2021). Thus the number of occupied squares and counted individuals increased markedly between 2007 and 2010, after which it remained somewhat stable. The apparent increase in abundance in 2013 was also clearly detected by Kotaka et al. (2021), who found a sharp increase in the density of active nests in that year during monitoring 2005-2019. They attributed this to a temporary increase in nest availability caused by an outbreak of the pest beetle Plagiosterna formosana which first arrived on the island in 2010 (Kotaka 2014; see Figures 5 and 6c: Kotaka et al. 2021) and created a large number of temporary nest sites on dead trees.
While the declines in abundance (but note not occupied squares) between 2013 and 2016, and declines in nest density between 2015 and 2019, could be interpreted as reflecting a continuing population decline, Kotaka et al. (2021) considered them to be a temporary effect and not indicative of ongoing changes; the population trend is considered likely to be stable (N. Kotaka in litt. 2024).

In the future, the population trend of this species will recover further if the area of suitable habitat can be expanded, and mongoose control measures remain implemented. However, if mongoose control measures cease or fail, this species may decline (rapidly) again in the near-future (N. Kotaka in litt. 2024), and its extinction risk will appropriately increase. This should be very closely monitored.

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

Country/Territory	IBA Name
Japan	Yambaru, northern Okinawa forest

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Forest	Subtropical/Tropical Moist Lowland	suitable	resident
Forest	Subtropical/Tropical Moist Montane	major	resident
Altitude	0 - 500 m	Occasional altitudinal limits

Threat (level 1)	Threat (level 2)	Impact and Stresses
Agriculture & aquaculture	Annual & perennial non-timber crops - Agro-industry farming	Timing		Scope		Severity		Impact
		Past, Unlikely to Return		Minority (<50%)		Slow, Significant Declines		Past Impact
		Stresses Ecosystem degradation, Ecosystem conversion
Biological resource use	Logging & wood harvesting - Unintentional effects: (subsistence/small scale) [harvest]	Timing		Scope		Severity		Impact
		Past, Unlikely to Return		Minority (<50%)		Slow, Significant Declines		Past Impact
		Stresses Ecosystem degradation
Climate change & severe weather	Storms & flooding	Timing		Scope		Severity		Impact
		Future		Whole (>90%)		Unknown		Unknown
		Stresses Ecosystem degradation, Ecosystem conversion
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Urva auropunctata	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		No decline		Low Impact: 4
		Stresses Reduced reproductive success, Species mortality
Residential & commercial development	Tourism & recreation areas	Timing		Scope		Severity		Impact
		Past, Unlikely to Return		Minority (<50%)		Slow, Significant Declines		Past Impact
		Stresses Ecosystem degradation, Ecosystem conversion
Transportation & service corridors	Roads & railroads	Timing		Scope		Severity		Impact
		Past, Unlikely to Return		Minority (<50%)		Slow, Significant Declines		Past Impact
		Stresses Ecosystem degradation, Ecosystem conversion

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Recommended citation
BirdLife International (2024) Species factsheet: Okinawa Woodpecker Dendrocopos noguchii. Downloaded from https://datazone.birdlife.org/species/factsheet/okinawa-woodpecker-dendrocopos-noguchii on 23/12/2024.
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 23/12/2024.