The mysterious
extinctRyūkyū kingfisher, known from a single
specimen, is sometimes placed as a subspecies (T. c. miyakoensis; Fry et al. 1992), but was declared invalid by the
International Ornithological Congress in 2022, rendering the species
monotypic.[3] Among-island differences in
morphological, behavioral, and ecological characteristics have been determined sufficient that
Micronesian kingfisher populations, of which the Guam kingfisher was considered a subspecies, should be split into separate species.[4]
This is a brilliantly colored, medium-sized kingfisher, 20–24 cm in length. They have iridescent blue backs and rusty-cinnamon heads. Adult male Guam kingfishers have cinnamon underparts while females and juveniles are white below. They have large laterally-flattened bills and dark legs. The calls of Micronesian kingfishers are generally raspy chattering.[5]
Behavior
Guam kingfishers were
terrestrial forest generalists that tended to be somewhat secretive. The birds nested in cavities excavated from soft-wooded trees and
arborealtermitaria, on Guam.[6] Micronesian kingfishers defended permanent territories as breeding pairs and family groups.[7] Both sexes care for young, and some offspring remain with parents for extended periods. Research suggests that thermal environment has the potential to influence reproduction.[7]
Feeding
In the wild, the Guam kingfisher feeds on grasshoppers, skinks, insects, and small crustaceans. The birds dive and capture their prey on the ground, similar to other species of kingfishers that dive for fish in water.[8]
Conservation status
The Guam kingfisher population was
extirpated from its native habitat after the introduction of
brown tree snakes.[9] It was last seen in the wild in 1986, and the birds are now U.S. listed as
endangered.[5] The Guam kingfisher persists as a captive population of fewer than two hundred individuals (as of 2017) in US mainland and Guam breeding facilities. However, there are plans to
reintroduce the Guam birds to
Palmyra Atoll, and potentially also back to their native range on Guam if protected areas can be established and the threat of the
brown tree snakes is eliminated or better controlled.[2][5] Unfortunately, however, three decades of research and management have yielded little hope for safe habitats on Guam.[citation needed]
Laws, Rebecca J.; Kesler, Dylan C. (2012). "A Bayesian network approach for selecting translocation sites for endangered island birds". Biological Conservation. 155: 178–185.
doi:
10.1016/j.biocon.2012.05.016.
Fry, C. Hilary; Fry, Kathie; Harris, Alan (1992). Kingfishers, Bee-eaters, and Rollers. Princeton, NJ: Princeton University Press.
ISBN978-0713680287.
Haig, Susan M.; Ballou, Jonathan D. (1995). "Genetic Diversity in Two Avian Species Formerly Endemic to Guam". The Auk. 112 (2): 445–455.
doi:
10.2307/4088732.
JSTOR4088732.
Haig, S. M.; Ballou, J. D.; Casna, N. J. (1995). "Genetic Identification of Kin in Micronesian Kingfishers". Journal of Heredity. 86 (6): 423–431.
doi:
10.1093/oxfordjournals.jhered.a111616.
Marshall, Samuel D. (1989). "Nest Sites of the Micronesian Kingfisher on Guam". The Wilson Bulletin. 101 (3): 472–477.
JSTOR4162756.
Pratt, H.D., P.L. Bruner, and D.G. Berrett. 1987. The Birds of Hawaii and the Tropical Pacific. Princeton University Press. Princeton, NJ.
Savidge, Julie A. (1987). "Extinction of an Island Forest Avifauna by an Introduced Snake". Ecology. 68 (3): 660–668.
doi:
10.2307/1938471.
JSTOR1938471.
U.S. Fish and Wildlife Service, 2004. Draft Revised Recovery Plan for the Sihek or Guam Micronesian Kingfisher (Halcyon cinnamomina cinnamomina).
U.S. Fish and Wildlife Service, 1984. Endangered and threatened wildlife and plants: determination of endangered status for seven birds and two bats on Guam and the Northern Mariana Islands. Federal Register 50 CFR Part 17 49(167), 33881–33885.
U.S. Fish and Wildlife Service, 2004. Draft Revised Recovery Plan for the Sihek or Guam Micronesian Kingfisher (Halcyon cinnamomina cinnamomina). U.S. Fish and Wildlife Service, Portland, OR.