Chattering Kingfisher (Todiramphus tutus) is found on seven islands: Maupiti, Bora Bora, Tahaa, Raiatea and Huahine in French Polynesia and Atiu and Mauke in the Cook Islands. It is considered to be widespread and common on Atiu and Mauke (McCormack 2007, Woodall and Kirwan 2018), but may be declining and have a very small population on Bora Bora (Woodall and Kirwan 2018). It is found in primary and secondary forest, old plantations, cultivated land with trees, and gardens (Woodall and Kirwan 2018). The species is currently listed as Least Concern on the IUCN Red List.
This species was previously believed to occur on Tahiti, but it has recently been clarified that this is not the case (van der Vliet and Jansen 2015). Hence, we are undertaking a review of the species’s Red List Category.
Our current information on the species’s conservation status will now be compared to all Red List Criteria.
Criterion A – We do not have any quantified information about the species’s population or habitat trends. Therefore, the species cannot be assessed under this criterion.
Criterion B – The species’s range islands are distributed over a large area and the species’s Extent of Occurrence (EOO), as measured by a single minimum convex polygon enclosing the species’s entire range, does not fall beneath the thresholds for listing as threatened under Criterion B1. The species’s Area of Occupancy (AOO), measured as the total area of 4 km2 grid squares intersecting the species’s mapped range, has been estimated at 944 km2. This falls beneath the threshold for listing the species as Vulnerable under Criterion B2. However, to list the species as Vulnerable on the Red List under Criterion B2, two further conditions must be met.
The species is not considered to be severely fragmented according to the IUCN definition (IUCN Standards and Petitions Subcommittee 2017). Considering the main threat to the species to be habitat loss, the species is likely to have more than ten locations*. Although the population is thought to have declined in Bora Bora (Woodall and Kirwan 2018), we do not currently have information from which to estimate, infer or project a continuing decline in population size, or area or quality of habitat. Therefore, the species does not fully meet two conditions and is listed as Least Concern under Criterion B.
Criterion C – The species’s population size has not previously been estimated and no survey data are available. Based on the area of the mapped range (450 km2), recorded population densities of other Todiramphus species in the same region (ranging from 5.6/km2 for T. chloris in American Samoa [Engbring 1989] and 8/km2 for T. cinnamominus in Federated States of Micronesia [Engbring 1990], to 43/km2 for T. chloris in Northern Mariana Islands [Craig 1996]) and making a rough assumption that only 45% of the species’s range is likely to be occupied, the species’s population size may be roughly estimated to number approximately 1,134 – 8,708 individuals. This roughly equtes to 756 – 5,805 mature individuals. This range falls beneath the thresholds for Endangered and Vulnerable under Criterion C. Given that the species is described as widespread and common in Atiu and Mauke (Cook Islands), the actual population size may be more likely to fall within the band 2,500 – 9,999 mature individuals, meeting the threshold for Vulnerable under Criterion C. However, for the species to be listed as threatened under Criterion C, there must be quantitative evidence from which to estimate, infer or project a continuing decline in population size. Additionally, there must be evidence from which to estimate a decline at a rate exceeding a threshold (under Criterion C1), or the species must have a particular subpopulation structure or be undergoing extreme fluctuations (under Criterion C2).
We do not have a quantified estimate of a rate of continuing decline, so the species does not warrant listing as threatened under Criterion C1. Although the population is thought to have declined in Bora Bora (Woodall and Kirwan 2018), we do not currently have information from which to estimate, infer or project a continuing decline. This means that the species also cannot be listed as threatened under Criterion C2. However, if a continuing decline in population size is suspected, the species could qualify for listing as Near Threatened under this criterion. Given the species’s small population and its distribution across multiple islands, it is likely that the population is composed of subpopulations of no more than 1,000 mature individuals each, meeting Criterion C2a(i).
Therefore, based on our current information, the species could qualify as Near Threatened because it approaches the thresholds for listing as Vulnerable under Criterion C2a(i). If further evidence is made available that allows us to estimate, infer or project a continuing decline, the species may qualify as Vulnerable under Criterion C. If, in addition, further evidence suggests that the population size is likely to be fewer than 2,500 mature individuals, the species could be listed as Endangered under Criterion C.
Criterion D – Based on the range of population estimates described above, the species’s population may meet the threshold for listing the species as Vulnerable under Criterion D. However, the species’s true population size may be more likely to fall above the threshold of 1,000 mature individuals, thus it may be more appropriate to assess the species as Near Threatened under Criterion D1.
Criterion E – To the best of our knowledge no quantitative assessment of the probability of extinction has been conducted for Chattering Kingfisher, and so it cannot be assessed against this criterion.
To get a clearer assessment of the species’s status, information is requested on the Chattering Kingfisher’s population, habitat and threats. In particular, we require quantitative information on the species’s population size and ongoing trends across its range, as well as current trends in the extent and quality of its habitat.
Please note that this topic is not designed to be a general discussion about the ecology of the species, rather a discussion of the species’s Red List status. Therefore, please make sure your comments are about the proposed listing.
* The term ‘location’ defines a geographically or ecologically distinct area in which a single threatening event can rapidly affect all individuals of the taxon present. The size of the location depends on the area covered by the threatening event and may include part of one or many subpopulations. Where a taxon is affected by more than one threatening event, location should be defined by considering the most serious plausible threat (IUCN 2001, 2012).
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.
Craig, R. J. (1996) Seasonal population surveys and natural history of a Micronesian bird community. Wilson Bulletin 108: 246-267.
Engbring, J. (1989) A 1986 survey of the forest birds of American Samoa. USFWS.
Engbring, J. (1990) Micronesian Forest Bird Surveys, The Federated States: Pohnpei, Krosrae, Chuuk, and Yap. USFWS.
IUCN (2001) IUCN Red List Categories and Criteria: Version 3.1. Species Survival Commission. IUCN, Gland, Switzerland and Cambridge, UK.
IUCN (2012) IUCN Red List Categories and Criteria: Version 3.1. Second Edition. IUCN, Gland, Switzerland and Cambridge, UK.
IUCN Standards and Petitions Subcommittee (2017) Guidelines for using the IUCN Red List Categories and Criteria. Version 13 (March 2017). Retrieved from http://www.iucnredlist.org/documents/RedListGuidelines.pdf on 18 September 2018.
McCormack, G. (2007) Cook Islands Biodiversity Database, Version 2007.2. Cook Islands Natural Heritage Trust, Rarotonga. Retrieved from http://cookislands.bishopmuseum.org on 18 September 2018.
van der Vliet, R.E. & Jansen, J.J.F.J. (2015) The chequered history of Chattering Kingfisher Todiramphus tutus on Tahiti. II: review of status. Bull. Brit. Orn. Club 135(2): 121–130.
Woodall, P.F. & Kirwan, G.M. (2018). Chattering Kingfisher (Todiramphus tutus). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. Retrieved from https://www.hbw.com/node/55773 on 18 September 2018.