Satoe Kasahara

Abundance of birds in Fukushima as judged from Chernobyl

The effects of radiation on abundance of common birds in Fukushima can be assessed from the effects of radiation in Chernobyl. Abundance of birds was negatively related to radiation, with a significant difference between Fukushima and Chernobyl. Analysis of 14 species common to the two areas revealed a negative effect of radiation on abundance, differing between areas and species. The relationship between abundance and radiation was more strongly negative in Fukushima than in Chernobyl for the same 14 species, demonstrating a negative consequence of radiation for birds immediately after the accident on 11 March 2011 during the main breeding season in March-July, when individuals work close to their maximum sustainable level.

Conspecific Egg Removal Behaviour in Eurasian Tree Sparrow Passer montanus

In farmland in central Honshu, Japan, conspecific infanticide was recorded in five out of 68 breeding attempts of Eurasian Tree Sparrow Passer montanus in 2011 and 2012 including one suspected case. The number of eggs lost by infanticide accounted for 20% in 2011 and for 24.1% in 2012 of the total egg and nestling losses. In three out of five cases, subsequent nesting took place in the nest box where infanticide had caused the loss of a clutch, twice by the perpetrator and once by unknown breeders. In this population, infanticide was a major cause of breeding failure.

Effects of the Climatic Conditions at Breeding, Stopover and Wintering Sites on the Number of Juvenile Whooper Swans Cygnus cygnus Wintering in Japan

Abstract We studied the effects of climatic conditions on the number of juvenile Whooper Swans wintering in Aomori Prefecture, northern Japan, from 1983 to 2009. We analyzed the relationship between the abundance of wintering juveniles and eight climatic variables using generalized linear models; (May and June temperatures recorded in Cokurdah, Yakutia, Russia within their breeding range, the temperature in Nikolayevsk-na-Amure within their migratory stopover range, snowfall in Obihiro, Hokkaido, a stopover site, and temperature and snowfall of the previous and present years in Nobechi, Aomori Prefecture, where they winter. The models with good fit showed that the mean highest daily temperatures in May on the breeding grounds had a positive effect on the abundance of wintering juveniles, while the total snowfall of both previous and present years in the wintering range had a negative effect on juvenile abundance.

Badge Size of Male Eurasian Tree Sparrows Passer montanus Correlates with Hematocrit During the Breeding Season

Abstract We investigated whether the badge size of the Eurasian Tree Sparrow Passer montanus is correlated with morphological traits and hematocrit during the breeding season in order to elucidate the function of badge size as a potential signal of body size and physiological condition. We found a positive correlation in males between badge size and hematocrit, but not in females. As individuals with larger hematocrit values can transport more oxygen to their tissues or organs, male badge size may be linked with oxygen transport ability. We suggest that male badge size may be a signal of physiological status.