The Ryukyu kingfisher (''Todiramphus cinnamominus miyakoensis'') is an enigmatic taxon of

tree kingfisher The tree kingfishers, also called wood kingfishers or Halcyoninae, are the most numerous of the three family (biology), subfamilies of birds in the kingfisher family, with around 70 species divided into 12 genus, genera, including several specie ...

. It is

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

and is only known from a single specimen. Its taxonomic status is doubtful; it is most likely a

subspecies In Taxonomy (biology), biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (Morphology (biology), morpholog ...

of the

Guam kingfisher The Guam kingfisher (''Todiramphus cinnamominus''), called in Chamorro, is a species of kingfisher from the United States Territory of Guam. It is restricted to a captive breeding program following its extinction in the wild due primarily to ...

, which would make its scientific name ''Todiramphus cinnamominus miyakoensis''. As the specimen is at the Yamashina Institute for

Ornithology Ornithology, from Ancient Greek ὄρνις (''órnis''), meaning "bird", and -logy from λόγος (''lógos''), meaning "study", is a branch of zoology dedicated to the study of birds. Several aspects of ornithology differ from related discip ...

, the question could be resolved using

DNA Deoxyribonucleic acid (; DNA) is a polymer composed of two polynucleotide chains that coil around each other to form a double helix. The polymer carries genetic instructions for the development, functioning, growth and reproduction of al ...

sequence analysis; at any rate, the Guam kingfisher is almost certainly the closest relative of the Ryukyu bird. The

IUCN The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the status ...

considers this bird a subspecies and has hence struck it from its redlist. The one known bird, probably a male, was according to its label collected on

Miyako-jima is the largest and the most populous island among the Miyako Islands of Okinawa Prefecture, Japan. Miyako Island is administered as part of the City of Miyako Island, which includes not only Miyako Island, but also five other islands. Geogr ...

, the main island of the Miyako group,

Ryūkyū Shotō The , also known as the or the , are a chain of Japanese islands that stretch southwest from Kyushu to Geography of Taiwan, Taiwan: the Ryukyu Islands are divided into the Satsunan Islands (Ōsumi Islands, Ōsumi, Tokara Islands, Tokara and A ...

, on February 5, 1887. While it is often and correctly stated that specimen labels may be incorrect or misleading, the locality, to the northwest of the extant populations of ''Todiramphus cinnamominus'', seems sound in a biogeographical sense. At least the specimen labels of Ryukyu collections by later Japanese collectors are usually very reliable; whether this is true for earlier collection too is not known. The only differences between the Miyako-jima bird and males of the

Guam Guam ( ; ) is an island that is an Territories of the United States, organized, unincorporated territory of the United States in the Micronesia subregion of the western Pacific Ocean. Guam's capital is Hagåtña, Guam, Hagåtña, and the most ...

kingfisher (the nominate subspecies of the Micronesian kingfisher; presently only surviving in captivity) are the former's lack of a black nape band and the red feet (black in Guam birds). The bill color is unknown due to damage to the specimen, and supposed differences in the proportion of the

remiges Flight feathers (''Pennae volatus'') are the long, stiff, asymmetrically shaped, but symmetrically paired pennaceous feathers on the wings or tail of a bird; those on the wings are called remiges (), singular remex (), while those on the ta ...

are almost certainly an artifact of specimen preparation. Indeed, the specimen was not recognized as distinct until some 30 years after its collection. If the bird was indeed a resident of the Miyako group (and as there was better habitat on neighboring Irabu-jima, it is probable that it would have been found there too), it became extinct in the late 19th century. While this seems early, the population must have always been small as there never was much habitat available in historic times. Certainly, thorough research in the early 20th century failed to find the bird again. The reasons for the disappearance of the population would have been land clearance and draining of wetlands for agriculture.

References

Todiramphus Controversial bird taxa Extinct birds of Oceania Extinct animals of Asia Extinct animals of Japan Birds of the Ryukyu Islands Birds described in 1919 Taxa named by Nagamichi Kuroda Species known from a single specimen {{Coraciiformes-stub