2024 Volume 20 Pages S25-S34
Two juvenile Eurasian Bullfinches Pyrrhula pyrrhula were captured on 20 June 2023, during a constant-effort mist-netting survey conducted in the lowland forest (200 m asl) of southeast Sapporo, Hokkaido, during the breeding season. They had juvenile plumages, before molting to the first winter plumage. As these two birds were captured in the same net at the same time, they seem to be a part of a family or juvenile flock. Several studies have reported that the Eurasian Bullfinch bred in low-elevation sites, especially in the north and east of Hokkaido. On the other hand, in southwestern Hokkaido including Sapporo City, there have been no observations or captured data of juvenile birds at lower than 300 m during the breeding season (from June to August), and there are few reliable breeding records of bullfinch in the area. It is more likely that these juvenile birds fledged from the nest of a breeding pair that accidentally bred in the vicinity of the capture site, rather than fledging in the high-elevation area and moving to the lowland. Whether this possible breeding record of bullfinches in the lowland forest of western Hokkaido is a rare event or will continue to occur in the future needs to be carefully monitored.
