新潟県におけるフクロウ類の生息状況

抄録

Various records, supplemented by field research, were employed to verify the status of owls (Family Strigidae) in Niigata Prefecture, located along the Japan Sea side of central Honshu. Records surveyed included injured birds reported from October 1971 through March 2001, and dead specimens brought to government branches from April 1978 through March 1988. For purpose of analysis, the Prefecture was divided into four sections (Fig. 1); north (1), central (2), and south (3) areas of the mainland, and Sado Island (4). A total of 6 owl species were identified.
Ural Owl (Strix uralensis): This species was by and away the most common, with 288 injured and 297 dead individuals reported. In addition, banding research has demonstrated that this owl shows a strong tendency to remain in a restricted area. Common in all three mainland areas but absent from Sado Island. Collared Scops Owl (Otus bakkamoena): A resident throughout the prefecture, most common on Sado Island. Research has shown that birds on the island lay their eggs from April through May, and the chicks fledge out in June; while on the mainland the eggs are laid in May and June, and fledging takes place in July. Scops Owl (Otus scops): Summer breeder throughout mainland areas, most common in north area. On Sado Island is primarily a passage migrant. No records occur from December through March, indicating that this species does not spend the winter in Niigata. Long-eared Owl (Asio otus): Until the 1960s this species was rare in the prefecture, but numbers have increased since the 1970s. A resident species, this owl is unusual in that it winters in roosts of up to several dozen individuals. Brown Hawk-owl (Ninox scutulata): Records run from May through November, indicating that this species breeds the Prefecture but does not winter. In adeition, birds that breed further north pass through Niigata on their migration routes. Short-eared Owl (Asio flammeus): Records occur from October through March, indicating that this owl is primarily a winter visitor in Niigata. The total number of records was lowest among the six species.