Japanese Murrelet
Synthliboramphus wumizusume
冠海雀
Introduction
A small seabird in the auk family (Alcidae). Monotypic species occurring along remote rocky coasts and in offshore waters of Japan, with post-breeding dispersal to Sakhalin and off South Korea. Inhabits boreo-cool and temperate-subtropical waters of the northwest Pacific. Breeds on small rocky islets and uninhabited islands. As of 2017, the global population is estimated at 2,500–10,000 individuals, making it the rarest alcid and the most at risk of extinction. Classified as Vulnerable on the IUCN Red List.
Description
A small seabird measuring 24–26 cm in length with a 43 cm wingspan and weighing 164–183 g. The upperparts are blackish and bluish grey, while the throat and underparts are white. The legs and feet are yellowish grey, and the short, thick bill is bluish grey with a darker culmen. The iris is dark brown. The head is black with a white stripe extending from the top of each eye that meets on the nape, though this is less visible in winter plumage. In summer, a distinctive crest of black feathers measuring 3–5 cm in length adorns the head, absent during winter. Juveniles resemble winter adults but show browner tones on the head and upperparts.
Identification
Distinguished from the similar Ancient murrelet (Synthliboramphus antiquus), which overlaps in much of its range, by the presence of a summer crest of black feathers 3–5 cm long. This crest is absent in winter plumage, making identification more challenging during non-breeding season. Both species have white head stripes, but the Japanese murrelet is the only crested member of the genus in its range. The all-dark head with crest in breeding plumage is a reliable field mark.
Distribution & Habitat
Breeds on small rocky islets and coasts of Japan from Nanatsujima in Ishikawa Prefecture north to Tori-shima in the Izu Islands of Tokyo Metropolis south, with main concentrations on Birojima in Miyazaki Prefecture and the Izu Islands. After breeding, disperses along Honshū and Kyūshū in warm waters of the Kuroshio and Tsushima Currents, with records from the Southern Kuriles, Sakhalin, Primorsky Krai, Fujian, South Korea, and Taiwan. Returns to breeding areas around December and winters mostly offshore from breeding locations.
Behavior & Ecology
Diet consists primarily of krill, other planktonic crustaceans, crangonid shrimp, and larval and small pelagic fish including Pacific herring, sculpin, smelt, sand eels, and sandlances. Nests in rocky crevices, gaps between stone piles, and among grasses on uninhabited islands. Lays typically two eggs, a week apart, from late March to early April. Both parents share month-long incubation duties almost equally. Precocial chicks leave the nest with parents on the second night after hatching. Vocalizations include a quiet contact call 'ch-ch-chi-chi', flight call 'peee-p-p-p', and various nesting calls.
Conservation
Classified as Vulnerable on the IUCN Red List with an estimated global population of 2,500–10,000 individuals as of 2017. Major threats include by-catch in drift nets, disturbance from recreational fishing waste attracting scavengers, and predation by rats, feral cats, large-billed crows, and black-tailed gulls. Historical egg harvesting and use of the Ōnohara Islands as a US Air Force bombing range in 1951–1952 caused significant impacts. Listed on Appendix I of CMS and legally protected in Japan as a Natural Monument since 1975. Adopted as a marine conservation symbol by the Wild Bird Society of Japan in 2009. Classified as Vulnerable on Japan's Ministry of the Environment Red List since 1991.
Culture
In Japan, known locally as kanmuri-umisuzume or 'crested sea sparrow' (冠海雀), where umisuzume is the vernacular name for the Ancient murrelet. The species was adopted as a symbol of marine conservation by the Wild Bird Society of Japan in 2009. Designated a Natural Monument under Japan's 1950 Law for the Protection of Cultural Properties in 1975.
Source: Wikipedia · CC BY-SA 3.0
Taxonomy
- Order
- Charadriiformes
- Family
- Alcidae
- Genus
- Synthliboramphus
- eBird Code
- japmur1
Distribution
breeds western North Pacific coasts and islands from off western Honshu, Kyushu, and Izu Is. (central and southern Japan), south of Korean Peninsula, and perhaps far southeastern Russia; winters Hokkaido to southeastern Japan
Data Sources
Species description from Wikipedia, licensed under CC BY-SA 3.0.
Taxonomy data from AviList 2025.