5 thoughts on “Taiwan Green-pigeon (Treron formosae)”
The window for consultation is now temporarily closed and we are unable to accept any more comments until 6 February 2023. We will now analyse and interpret the new information, and we will post a preliminary decision on this species’ Red List status on this page on 6 February 2023, when discussions will re-open.
Based on available information, our preliminary proposal for the 2023 Red List would be to adopt the proposed classifications outlined in the initial forum discussion.
There is now a period for further comments until the final deadline on 12 February 2023, after which the recommended categorisations will be put forward to IUCN.
The final 2023 Red List categories will be published on the BirdLife and IUCN websites in December 2023, following further checking of information relevant to the assessments by both BirdLife and IUCN.
Please see the comments from Dr. Ruey-Shing Lin of the Taiwan Endemic Species Research institute and Mr. Cheng-Ching Chiu of the Taiwan Wild Bird Federation
Comments on the conservation status of Taiwan Green-pigeon (Treron formosae)
Ruey-Shing Lin and Cheng-Ching Chiu
Based on the information provided, we believe that the population estimate of Taiwan Green-pigeon (Treron formosae) needs to be adjusted. Although eBird shows that Taiwan Green-pigeon is well recorded and widely distributed in Taiwan. However, to our knowledge, Taiwan Green-pigeon often aggregates and nomads significantly during the non-breeding season. Birdwatching is quite active in Taiwan, and with relatively large and reliable records, it quite clearly shows that Taiwan Green-pigeon breeds only on two small islands in the Pacific Ocean, Green Island and Orchid Island which are close to Taiwan main island. Taiwan Green-pigeon is not uncommon in Green Island and Orchid Island during the breeding season. However, the areas of these two islands, which are 15 and 47 square km, respectively, are small. Lin et al. (2016) estimated its population size was fewer than 1,000 mature individuals. In addition, if the data source of the population estimate is Brazil (2009), it should be reminded that the Brazil (2009) population estimate for Taiwan Green-pigeon is RB3-4, with B3 = scarce (100-10,000 pairs) and B4 = rare (fewer than 100 pairs), so the population estimate for Taiwan Green-pigeon should be close to 100-1,000 pairs and should not be interpreted as having 10,000-19,999 adults. Therefore, we suggest that the estimate of the Taiwan green-pigeon global population size should be no more than 2,500 matured individuals, and their conservation categories need to be adjusted accordingly.
Many thanks to everyone who has contributed to this discussion. We greatly appreciate the time and effort invested in commenting. The window for consultation is now closed and we are unable to accept any more comments. We will analyse and interpret available information, and we will post a final decision on this species’ Red List status on this page on 20 February 2023.
Recommended categorisation to be put forward to IUCN
Following further review, the recommended categorisation for this species has been changed.
Taiwan Green-pigeon is now recommended to be retained as Near Threatened, approaching the threshold for listing as threatened under Criteria C2a(i); D1.
This decision is reached in response to comments made by Ruey-Shing Lin and Cheng-Ching Chiu (via S. Pursner) which indicate that a significant misinterpretation of the likely population size of the species. Accordingly, the global population size (including in the Philippines) is revised to 1,250-2,000 mature individuals. Consequently, the species approaches the threshold for listing as Vulnerable under Criterion D1 (<1,000 mature individuals) and is therefore listed as Near Threatened. The map has also been changed to reflect the information provided.
Many thanks for everyone who contributed to the 2023.1 GTB Forum process. The final 2023 Red List categories will be published on the BirdLife and IUCN websites in December 2023, following further checking of information relevant to the assessments by both BirdLife and IUCN.
The window for consultation is now temporarily closed and we are unable to accept any more comments until 6 February 2023. We will now analyse and interpret the new information, and we will post a preliminary decision on this species’ Red List status on this page on 6 February 2023, when discussions will re-open.
Preliminary proposal
Based on available information, our preliminary proposal for the 2023 Red List would be to adopt the proposed classifications outlined in the initial forum discussion.
There is now a period for further comments until the final deadline on 12 February 2023, after which the recommended categorisations will be put forward to IUCN.
The final 2023 Red List categories will be published on the BirdLife and IUCN websites in December 2023, following further checking of information relevant to the assessments by both BirdLife and IUCN.
Please see the comments from Dr. Ruey-Shing Lin of the Taiwan Endemic Species Research institute and Mr. Cheng-Ching Chiu of the Taiwan Wild Bird Federation
Comments on the conservation status of Taiwan Green-pigeon (Treron formosae)
Ruey-Shing Lin and Cheng-Ching Chiu
Based on the information provided, we believe that the population estimate of Taiwan Green-pigeon (Treron formosae) needs to be adjusted. Although eBird shows that Taiwan Green-pigeon is well recorded and widely distributed in Taiwan. However, to our knowledge, Taiwan Green-pigeon often aggregates and nomads significantly during the non-breeding season. Birdwatching is quite active in Taiwan, and with relatively large and reliable records, it quite clearly shows that Taiwan Green-pigeon breeds only on two small islands in the Pacific Ocean, Green Island and Orchid Island which are close to Taiwan main island. Taiwan Green-pigeon is not uncommon in Green Island and Orchid Island during the breeding season. However, the areas of these two islands, which are 15 and 47 square km, respectively, are small. Lin et al. (2016) estimated its population size was fewer than 1,000 mature individuals. In addition, if the data source of the population estimate is Brazil (2009), it should be reminded that the Brazil (2009) population estimate for Taiwan Green-pigeon is RB3-4, with B3 = scarce (100-10,000 pairs) and B4 = rare (fewer than 100 pairs), so the population estimate for Taiwan Green-pigeon should be close to 100-1,000 pairs and should not be interpreted as having 10,000-19,999 adults. Therefore, we suggest that the estimate of the Taiwan green-pigeon global population size should be no more than 2,500 matured individuals, and their conservation categories need to be adjusted accordingly.
Citation:
Lin, R. S., et al. “The red list of birds of Taiwan, 2016.” Endemic Species Research Institute and Forestry Bureau, Council of Agriculture, Executive Yuan, Nantou, Taiwan. [online] URL: https://www.researchgate.net/publication/312045198_The_Red_List_of_Birds_of_Taiwan_2016 (2016)
Many thanks to everyone who has contributed to this discussion. We greatly appreciate the time and effort invested in commenting. The window for consultation is now closed and we are unable to accept any more comments. We will analyse and interpret available information, and we will post a final decision on this species’ Red List status on this page on 20 February 2023.
Recommended categorisation to be put forward to IUCN
Following further review, the recommended categorisation for this species has been changed.
Taiwan Green-pigeon is now recommended to be retained as Near Threatened, approaching the threshold for listing as threatened under Criteria C2a(i); D1.
This decision is reached in response to comments made by Ruey-Shing Lin and Cheng-Ching Chiu (via S. Pursner) which indicate that a significant misinterpretation of the likely population size of the species. Accordingly, the global population size (including in the Philippines) is revised to 1,250-2,000 mature individuals. Consequently, the species approaches the threshold for listing as Vulnerable under Criterion D1 (<1,000 mature individuals) and is therefore listed as Near Threatened. The map has also been changed to reflect the information provided.
Many thanks for everyone who contributed to the 2023.1 GTB Forum process. The final 2023 Red List categories will be published on the BirdLife and IUCN websites in December 2023, following further checking of information relevant to the assessments by both BirdLife and IUCN.