Garrulus lidthi 


Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Passeriformes Corvidae

Scientific Name: Garrulus lidthi
Species Authority: Bonaparte, 1851
Common Name(s):
English Amami Jay, Lidth's Jay
Identification information: 38 cm. Large, brown and blue jay. Dark blue head with blue-black forehead and lores. Dark blue tail. Rich chestnut back and underparts. White tips to flight and tail feathers. White flecking on throat. Bicoloured bill with horn tip and grey-blue base. Voice Unknown.

Assessment Information [top]

Red List Category & Criteria: Vulnerable C2a(ii) ver 3.1
Year Published: 2012
Date Assessed: 2012-05-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Contributor(s): Ishida, K. & Kominami, Y.
Facilitator/Compiler(s): Benstead, P., Bird, J., Crosby, M., Peet, N., Taylor, J.
This jay has a small population which is suspected to have declined, possibly as a result of increased levels of predation. It therefore qualifies as Vulnerable. If surveys reveal that the population is now increasing following predator control and forest regeneration, the species may warrant downlisting.

Previously published Red List assessments:
2008 Vulnerable (VU)
2007 Vulnerable (VU)
2004 Vulnerable (VU)
2000 Vulnerable (VU)
1996 Vulnerable (VU)
1994 Vulnerable (VU)
1988 Near Threatened (NT)

Geographic Range [top]

Range Description: Garrulus lidthi is endemic to the islands of Amami-ooshima, Kakeroma-jima, Uke-jima, Edateku-jima, part of the Nansei Shoto Islands, Japan (BirdLife International 2001, K. Ishida in litt. 2012). Its population was estimated at c.5,800 birds in the 1970s, but it may have declined through to the 1990s. It is precautionarily treated as undergoing a continuing decline overall, although it may have begun to increase since 2000, owing to alien predator control and natural forest regeneration (Yukihiro Kominami in litt. 2007), and may now be stable (K. Ishida in litt. 2012). Some observations indicate a population increase in the northern Kasari peninsula of Amami-ooshima (M. Takashi per K. Ishida in litt. 2012).

Countries occurrence:
Continuing decline in area of occupancy (AOO): Unknown
Extreme fluctuations in area of occupancy (AOO): No
Estimated extent of occurrence (EOO) - km2: 820
Continuing decline in extent of occurrence (EOO): Unknown
Extreme fluctuations in extent of occurrence (EOO): No
Number of Locations: 11-100
Continuing decline in number of locations: Unknown
Extreme fluctuations in the number of locations: No
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: The global population is estimated to number c.5,800 individuals (Nishidi 1974 in Brazil 1991), equivalent to c.3,900 mature individuals. It has been suggested that the population now exceeds 5,800 individuals (K. Ishida in litt. 2012); however, further research is required. The population is presently assumed to form one sub-population, but future genetic research (K. Ishida in litt. 2012) is expected to confirm whether this is the case.

Trend Justification:  It has been suggested that the population is now stable (K. Ishida in litt. 2012), but until new data are available the trend is precautionarily assumed to be negative. Although forest loss is unlikely to be having a significant impact upon this species, reduced reproductive success owing to nest predation by mammals is perhaps still leading to a moderate decline overall.
Current Population Trend: Decreasing
Additional data:
Number of mature individuals: 3900 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

Habitat and Ecology [top]

Habitat and Ecology: It occurs from sea-level into the hills, in subtropical evergreen broadleaved forest, coniferous forest, and in woodland around cultivation and human habitation, showing a significant preference for mature forest. It feeds on and caches the acorns of Castanopsis cuspidate, Quercus glauca and other oaks when they are available; if this food supply is exhausted birds will feed in agricultural fields (Yukihiro Kominami in litt. 2007). Sweet potato, insects, spiders, seeds, fruits, reptiles, including Okinawa pit-viper Trimeresurus flavoviridis, and birds are also included in its diet. It forages in trees and on the ground. Breeding takes place from late January or early February until May.

Systems: Terrestrial
Continuing decline in area, extent and/or quality of habitat: Unknown
Generation Length (years): 7.5
Movement patterns: Not a Migrant

Threats [top]

Major Threat(s): In some years, a high proportion of nests are predated by crows and mammals, and the small Asian mongoose Herpestes javanicus and snakes have been reported to prey on young birds and eggs. However, it is not known whether this apparently increased predation pressure will have a long-term effect on the population. The numbers of Large-billed Crow Corvus macrorhynchos on Amami-ooshima have recently increased, probably because of increased garbage disposal on the island. The effect of logging on its population is probably relatively small.

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
It is legally protected in Japan. Yuwandake on Amami-ooshima was established as a National Wildlife Protection Area, mainly for the conservation of this species and Amami Thrush Zoothera major. Several surveys and ecological studies have been completed. Introduced small Indian mongoose has been controlled within its range in recent years and as a result the species may now be stable or increasing. The increase in numbers of Large-billed Crows Corvus macrorhynchos on Amami-ooshima has been halted by improvements in refuse management (K. Ishida in litt. 2012).

Conservation Actions Proposed
Carry out surveys to obtain an up-to-date population estimate. Conduct regular surveys to ascertain whether the population is in fact stable or recovering. Conserve and restore remaining areas of mature forest on Amami-ooshima. Provide nest-boxes in areas where there is a shortage of suitable natural nesting sites. Control alien predators on Amami-ooshima.

Citation: BirdLife International. 2012. Garrulus lidthi. The IUCN Red List of Threatened Species 2012: e.T22705771A38131273. . Downloaded on 01 December 2015.
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