TThe species temperature index (STI), which is the mean temperature of the distribution area for bird species, has been calculated to evaluate the response of birds to climate change. In Japan, the ...STI for the breeding season has been calculated based on the results of the “Japan Breeding Bird Atlas.” Since the effects of climate change are more pronounced during the wintering season of birds (Lehikoinen et al. 2021), it is important to know the STI for the wintering season in Japan. We surveyed to determine the wintering distribution of birds in Japan between January 2016 and February 2022. However, the 40 km grid to collect distribution information used in this survey included areas of low to high elevation in the steep terrain of Japan which made the temperature differences within the grid too large to show STI. Since the Japanese archipelago extends from southwest to northeast, the distribution of any bird species in the Japanese archipelago can be indicated by the value obtained by adding latitude and longitude. Therefore, we calculated ”Latitude-Longitude Index” values that describe the distribution of various bird species during the wintering season in Japan to replace the STI. Here we present this method and propose it is a useful approach for studying the effects of climate change on birds.
A national survey of wintering birds was conducted in 1984-1986 by the Japanese Ministry of Environment. From 2016 to 2022 we completed a second survey of this program. With the cooperation of 396 ...participants, 105,660 questionnaires were collected across Japan, and combined with 788,148 data from other sources and databases. The information was aggregated into a national set of grid cells of approximately 40 km square, and compiled as a distribution map. We release this dataset to provide data to researchers and conservationists who wish to conduct various analyses to evaluate the distribution of birds in Japan during this period.Data download: https://doi.org/10.57368/data.birdresearch.21863967
To investigate the population dynamics of Donax semigranosus, its shell length was measured each month (March 2006 to March 2007) at Kujukuri Beach, Chiba Prefecture. To examine the effects of ...predation of the foot part by the sanderling Calidris alba, I conducted an experiment to test whether individuals whose foot parts were preyed upon could still burrow into the sand. The results showed that D. semigranosus began growing from March onwards, reproduced in the summer, and died in the winter. Therefore, the lifespan of the bivalves at the study site was estimated to be 1–1.5 years, similar to previous reports. Additionally, successive recruitments occur between August and October and overwintering occurs from December to March with a shell length of 6.9±1.5 mm (mean±SD, n=2,308). Unlike reports from the Sea of Japan, bivalves were common in the swash zone during winter (average of 10,701 ind./m2 from December to March). The experiment showed that most of the individuals (21 of 25 ind.) whose foot parts had been preyed upon were unable to burrow into the sand. Therefore, bivalves might be stranded due to wave action and eventually die on the beach. If the foot parts were less damaged, they could burrow into the sand and be able to regenerate the foot. Thus, foraging of foot parts by sanderlings could be a form of sublethal predation.
Using national wintering bird survey data, we examined changes in the wintering bird fauna in Japan from the 1980s to the 2010s and the factors influencing these changes. We also examined the ...differences between wintering and breeding seasons by comparing the data with breeding bird survey data. The results showed that wintering birds expanded their distribution area more northward compared to the breeding season from the 1980s to the 2010s. Non-forested ground-feeding birds, shallow-water foragers, and aerial foragers, for which low temperatures and snow cover are thought to be limiting factors in distribution, moved their distribution northward. Arboreal, submerged, and marine foragers moved the northern edge of their distribution northward. Aerial foraging birds moved northward in their distribution as temperatures increased, but other species did not move as far north in their distribution as expected by temperatures. These results suggest that the effects of climate change on wintering birds differ from those during the breeding season and are positive for birds whose distribution was restricted by cold.
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