Archived 2020 topic: Scarlet-breasted Lorikeet (Trichoglossus forsteni): request for information

BirdLife species factsheet for Scarlet-breasted Lorikeet

Scarlet-breasted Lorikeet (Trichoglossus forsteni; including subspecies mitchelli, djampeanus and stresemanni) occurs only across the Sundaic Islands of Indonesia; including Bali, Lombok, Sumbawa, Tanahjampea and Kalaotoa (BirdLife International, 2020). More recent findings however suggest the species is now restricted to only parts of Bali (extending into the Banyuwangi region of Java and Penida Island at its southern range), northern parts of Lombok, and only parts of West Nusa Tenggara (including areas within the vicinity of Mount Tambora) (eBird, 2020). Evidence and records of this species remains patchy and uncertain however, primarily due to difficulty in monitoring (Eaton et al., 2015). The species is also now extinct on multiple islands (including Sumbawa and the islands encompassing the Flores Sea [eBird, 2020]), with few observations recorded within the past 15 years (J. Eaton in litt. 2020).

Across its range, the species is found mostly in lowland and lower montane forests, as well as secondary growth and plantations, preferring disturbed vegetation and edges over closed-canopies (del Hoyo et al. 2020). Trapping for trade remains the significant threat towards this species. In the nearing islands of Maluku and North Maluku for example, the illegal parrot trade continues to increase extinction risk, with over 80% of rescued wildlife in 2018 across the islands (of 1,402 individuals) being parrots (1,135 individuals) (Setiyani and Ahmadi, 2020). Birdmarkets in the Balinese and Java regions have similarly shown that trapping amongst lorikeets remains common (Prihatmoko and Halaouate, 2018). Eastern Indonesia also remains the most frequently used transportation route for parrots and cockatoos, with both families being the second most trafficked bird group within the region (following songbird trade) (Indraswari et al., 2020).

The population of the Scarlet-breasted Lorikeet was previously estimated at 1,600-7,000 mature individuals, based on a tentative assessment of the locations retaining any numbers of the species. Based on existing population density estimates for the congener Coconut Lorikeet Trichoglossus haematodus (1.9-33 individuals/km2 for the island of Sumbawa [Marsden, 1999]), and precautionarily assuming that only 10% of the area of a newly mapped range (total range of c.  10,890 km2; see also eBird, 2020) is occupied by the species, the global population of Scarlet-breasted Lorikeet may number 2,069-35,937 individuals. This roughly equates to 1,380-23,960 mature individuals. Assuming that the population size is closer to the lower end of the estimate and considering its known rarity (J. Eaton in litt., 2020), the population size may actually number fewer than 1,500 mature individuals; tentatively placed here in the band of 1,000-2,499 mature individuals. This estimate may be revised as soon as new information is available.

Scarlet-breasted Lorikeet is currently listed as Vulnerable under Criterion C2a(i), based on a small and declining population, and fewer than 1,000 mature individuals in each subpopulation. However, information regarding the rarity of the species and unabated threats may warrant a change in Red List status. Therefore, the species will be re-assessed against all criteria:

Criterion A – Given the continued threat of trapping and sparse range, the species is likely to have undergone population size reduction across a three-generation period (15 years, Bird et al. 2020*). However, in the absence of numeric evidence of a rate of decline or any other tangible data (such as trade records), assessing the species under Criterion A is difficult. Over the past 15 years, the species has been difficult to locate, with very few reliable records (J. Eaton in litt., 2020). However, trapping for trade is likely continuing to affect the species; therefore, considering the intensive market for parrots across the general Sundaland region (Prihatmoko and Halaouate, 2018; Indraswari et al. 2020; Setiyani and Ahmadi, 2020), there are concerns that the population may be undergoing a rapid decline that could warrant a threatened status under Criterion A. In order to fully assess Scarlet-breasted Lorikeet under Criterion A, we request information on the population trend of the species, specifically encompassing the past 15 years. We would also welcome any new information on the effect of trapping for trade (or any other palpable threat) in the range of the species.

Criterion B ­– The species is thought to currently occupy a restricted range across few of the Sundaic Islands of Indonesia; this is also following extinctions on multiple islands (J. Eaton in litt., 2020; eBird, 2020). A new estimate for the Extent of Occurrence (EOO) is approximately 34,000 km2. However, this is too large to warrant a threatened listing under Criterion B1. A maximum Area of Occupancy (AOO) (using a 4 km2 grid over the area of mapped range) was estimated to be 12,400 km2. This is however an uncertain estimate and still remains above the threshold for a threatened category under Criterion B2. Scarlet-breasted Lorikeet therefore qualifies for Least Concern under this Criterion B.

Criterion C – The population of Scarlet-breasted Lorikeet is thought to number 1,000-2,499 mature individuals. Using this estimate tentatively however, the species would qualify for both a Vulnerable or Endangered status under Criterion C.  However, in order to qualify further under a threatened category, the species must meet further conditions.

The population is likely undergoing declines due to the intensity of trapping for trade. The exact rate of decline is however unknown, and thus the species cannot be assessed under sub-criteria C1. We also have no information on the population structure of the species. However, using a newly mapped range, it is tenable that the species may form at least 3-5 subpopulations. Based on a minimum population density of the congener Coconut Lorikeet (1.9 individuals/km2), and assuming that 10% of the range may be occupied, the largest subpopulation (total range c. 5,087 km2) may therefore contain approximately 640 mature individuals. This is below the required threshold for a Vulnerable status, but does not approach an Endangered status. However, presuming that the population size could be overestimated, the species could potentially number fewer than 250 mature individuals in its largest subpopulation. Overall however, data quality is unreliable and thus cannot warrant a definitive listing. Whilst the species will continue to meet Vulnerable under Criterion C2a(i), it may, given new information, qualify for an imminent change in status. We therefore request additional information regarding the population size and subpopulation structure of the Scarlet-breasted Lorikeet.

Criterion D – The population is tentatively placed in the band of 1,000-2,499 mature individuals. Considering the rarity of the species and assuming the true population size may number lower than 1,500 mature individuals, the species approaches the threshold for listing as threatened under Criterion D1. The species is therefore considered Near Threatened, nearly qualifying for a threatened status under Criterion D1.  

The species may however warrant a threatened category under Criterion D2. The estimated AOO is too large to meet or approach the threshold for a listing as Vulnerable under this criterion (<20km2). However, based on its restricted range and considering the extinction events that the species has undergone on several islands (J. Eaton in litt., 2020), the number of locations may have contracted. Under IUCN definitions, the term ‘location’ is a geographically or ecologically distinct area in which a single threatening event could eradicate all individuals of the taxon present (usually over one generation or 3-year period; whichever is longer) (IUCN Standards and Petitions Committee, 2019). Given the pressures of trapping for trade, the species’s locations may number fewer than 5, thus justifying a Vulnerable status. However, based on current information, this cannot be determined. We therefore request recent information on the effect of trapping for trade (or other potential threats) on the population size of this species, thus, enabling an accurate quantification on the number of locations of occurrence.

Criterion E – To the best of our knowledge no quantitative analysis of extinction risk has been conducted for this species. Therefore, it cannot be assessed against this criterion.

Therefore, based on available information, it appears the species still warrants a threatened status as Vulnerable under Criterion C2a(i). However, given uncertainty in the actual population size of the species, rates of decline, and the imminent pressures of trapping, it is difficult to assess the species against additional criteria. Therefore, we urgently seek recent information regarding the population size, structure, and trends of the Scarlet-breasted Lorikeet (Trichoglossus forsteni).

Please note that this topic is not designed to be a general discussion about the ecology of the species, rather a discussion of its Red List status. Therefore, please make sure your comments are relevant to the discussion outlined in the topic. By submitting a comment, you confirm that you agree to the Comment Policy.

*Bird generation lengths are estimated using the methodology of Bird et al. (2020), as applied to parameter values updated for use in each IUCN Red List for birds reassessment cycle. Values used for the current assessment are available on request. We encourage people to contact us with additional or improved values for the following parameters; adult survival (true survival accounting for dispersal derived from an apparently stable population); mean age at first breeding; and maximum longevity (i.e. the biological maximum, hence values from captive individuals are acceptable).

An information booklet on the Red List Categories and Criteria can be downloaded here and the Red List Criteria Summary Sheet can be downloaded here. Detailed guidance on IUCN Red List terms and definitions and the application of the Red List Categories and Criteria can be downloaded here.

References

Bird, J. P.; Martin, R.; Akçakaya, H. R.; Gilroy, J.; Burfield, I. J.; Garnett, S.; Symes, A.; Taylor, J.; Šekercioğlu, Ç.; Butchart, S. H. M. 2020. Generation lengths of the world’s birds and their implications for extinction risk. Conservation Biology online first view.

BirdLife International (2020). Species factsheet: Trichoglossus forsteni. http://www.birdlife.org (Accessed 21st May 2020).

Eaton, J. A., Shepherd, C. R., Rheindt, F. E., Harris, J. B. C., van Balen, S. B., Wilcove, D. S., and Collar, N. J. (2015). Trade-driven extinctions and near-extinctions of avian taxa in Sundaic Indonesia. Forktail; 31, 1-12.

eBird. 2020. eBird: An online database of bird distribution and abundance. Ithaca, NY, USA Available at: http://www.ebird.org.

del Hoyo, J., Collar, N., Kirwan, G. M., and Sharpe, C. J. (2020). Sunset Lorikeet (Tricjoglossus forsteni), version 1.0. In Birds of the World (del Hoyo, J., Elliot, A., Sargatal, J., Christie, D. A., and de Juana, E; Editiors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.railor3.01

Indraswari, K., Friedman, R. S., Noske, R., Shepherd, C. R., Biggs, D., Susilawati, C., and Wilson, C. (2020). It’s in the news: Characterising Indonesia’s wild bird trade network from media-reported seizure incidents. Biological Conservation; 243, 108431.

IUCN Standards and Petitions Committee. 2019. Guidelines for Using the IUCN Red List Categories and Criteria. Version 14. Prepared by the Standards and Petitions Committee. Downloadable from http://www.iucnredlist.org/documents/RedListGuidelines.pdf

Marsden, S.J. (1999). Estimation of parrot and hornbill densities using a point count distance sampling method. Ibis, 141(3), 327-390.

Prihatmoko, O. D., and Halaouate M. (2018). Yellow-crested Cockatoo: A hopeful trend in a significant population. In Psittascene: Magazing of the World Parrot Trust. https://www.parrots.org/files/psitta/2155/ps_summer_2018.pdf

Setiyani, A. D., and Ahmadi, M. A. (2020). An overview of illegal parrot trade in Maluku and North Maluku Provinces. Forest and Society; 4 (1), 48-60.

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8 Responses to Archived 2020 topic: Scarlet-breasted Lorikeet (Trichoglossus forsteni): request for information

  1. James Eaton says:

    There are no recent records from Kalaotoa, Kalao or Tanahjmpea (speaking with numerous villagers on the islands, they are unaware that such a species is present, even to those that hunt cockatoos), having personally visited the area six times since 2011. In addition, the islands are under massive habitat pressure now due to burning for cashew plantations (see forest cover change on Kalaotoa over past 5 years even).

    Currently, it is known from less than 50 birds away from Sumbawa, on Lombok and Bali. On Sumbawa, what published information there is, is extremely limited and doesn’t show anything positive, or any large flocks, with records all from the higher areas. If we look at the situation of other species under heavy trapping pressure on Sumbawa, ie Yellow-crested Cockatoo perhaps we can make a judgement on just how rare the species is likely to be.
    Though I have no personal information from Sumbawa, taking in mind the pressures of hunting on other parrot species (and cutting of nesting trees) on Sumbawa, Lombok, Bali and the Flores Sea Islands, then clearly it is in serious decline. I would not be surprised if a survey on Sumbawa revealed it to qualify for Critically Endangered status.

    James

  2. Simon Mahood says:

    A minor point, but I thought that the population on Nusa Penida was derived from confiscated and released cagebirds?

  3. There is a discovery of few birds of this species (T. f. mitchellii) this year 2020 on Bali. 6 to 7 birds have been recorded on the island and due to the pressure of trapping we have decided not to publish the exact location far and wide. This number is too low to be considered.
    On Sumbawa, there are still a few small populations remaining but looking at the numbers that have been offered for sale in the bird markets both on Java and Bali the species should definitely be uplisted.

  4. James Eaton says:

    Further to Sumbawa information, Collar in Forktail 33: Subspecific diagnoses in the Scarlet-breasted Lorikeet Trichoglossus forsteni, states the following:

    On Sumbawa the situation is unclear, but reports are consistently disconcerting: already in 1993 it was scarce/rare, ‘which may indicate a heavy trapping pressure on the island’ (Butchart et al. 1996), while numbers at Tatar Sepang, Important Bird Area in the south-west (BirdLife International 2017b), have plummeted in surveys, from over 200 in 1997 to around 50 in 2003 and as few as six in November 2016, this trend being attributed to trapping (Muhamad Salamuddin Yusuf in litt. 2017), and a two-day visit to Marente Forest in western Sumbawa yielded no records (A. Reuleaux in litt. 2017).

  5. Red List Team (BirdLife International) says:

    Many thanks to everyone who has contributed to this discussion. We greatly appreciate the time and effort invested by so many people in commenting. The window for consultation is now closed. We will analyse and interpret the new information and post a preliminary decision on this species’s Red List status on this page in early July.

    Thank you once again,
    BirdLife Red List Team

  6. Red List Team (BirdLife International) says:

    Preliminary proposal

    Based on available information and the rarity of the species as discussed above, the population of the Scarlet-breasted Lorikeet has been re-estimated into the band of 500-1,500 mature individuals. The species is also considered to be locally extirpated across many of its former Sundaic range due to continued trapping pressures. With fewer records of the species in recent years moreover, including only 50 birds being recorded away from Sumbawa, Lombok, and Bali (J. Eaton in litt. 2020), 6-7 birds of race mitchellii alone on Bali (M. Halaouate in litt. 2020), and 6 birds observed in 2016 in Sumbawa (Collar 2017), the population is likely highly restrictive. Therefore, we can precautionarily assume that the population has undergone rapid decline rates.

    Thus, our preliminary proposal for the 2020 Red List would be to list the Scarlet-breasted Lorikeet as Endangered under Criterion A2d+3d+4d; C2a(i). We however ask specifically for confirmation on the proposed rate of decline the species may have undergone in the past and the likelihood this many continue in the future.

    There is now a period for further comments until the final deadline in mid-July, after which the recommended categorisations will be put forward to IUCN.

    Please note that we will then only post final recommended categorisations on forum discussions where these differ from the initial proposal.

    The final 2020 Red List categories will be published on the BirdLife and IUCN websites in December 2020/January 2021 (information on the IUCN Red List update process can be found here), following further checking of information relevant to the assessments by both BirdLife and IUCN.

  7. Red List Team (BirdLife International) says:

    Recommended categorisation to be put forward to IUCN

    The final categorisation for this species has not changed. Scarlet-breasted Lorikeet is recommended to be listed as Endangered under Criteria A2d+3d+4d; C2a(i).

    Many thanks for everyone who contributed to the 2020 GTB Forum process. The final 2020 Red List categories will be published on the BirdLife and IUCN websites in December 2020/January 2021, following further checking of information relevant to the assessments by both BirdLife and IUCN.

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