House Sparrows Passer domesticus in Japan

S ummary .—House Sparrow Passer domesticus was recorded for the first time in Japan in 1990 on Rishiri Island, Hokkaido. Following this, further records were reported in four (possibly five) other areas, involving a total of eight sites, until 1994, with possible earlier sightings dating from 1988. The initial sightings were of singles (though two males were later suspected at two sites) and no young were found, though hybridisation with Eurasian Tree Sparrows P. montanus occurred at five sites. We suggest that the House Sparrows were probably windblown from the Far Eastern Federal District of Russia by an exceptional climatic event. It seems that colonisation of Japan by House Sparrow is unlikely. House Sparrow Passer domesticus has an extensive natural range that extends from coastal Western Europe and North Africa to Asia, as far east as Singapore in the south (colonised only in 1997), and the coast of the Far Eastern Federal District of Russia in the north. In the last-named region, it reached Nikolayevsk-na-Amure (53°08’N, 140°48’E) at the mouth of the Amur River in 1929 by following the Trans-Siberian railway during its construction. From there it spread to Okha (53°33’N, 143°01’E) on Sakhalin. More recently, the species has become established in many coastal towns from Magadan (59°38’N, 151°00’E) to Provideniya (64°31’N, 173°24’W) in the extreme north-east, through human introduction, and from there has spread, probably unassisted, across the Bering Strait to Alaska in the 21st century. House Sparrow, despite its recent decline in parts of Europe, is a dynamic species and the introduced populations in South America and subSaharan Africa are still extending their ranges. More surprising have been the reports of its occurrence in Japan at the end of the 20th century. This paper reviews the available data and speculates on the provenance of these birds.