Cesium concentration of nest materials of various tit species in an irradiated environment after the Fukushima Nuclear accident

Abstract

We measured the cesium [Cs-134 + Cs-137] concentration of nest material (mainly mosses) used by Japanese Tit Parus minor and Varied Tit Poecile varius (6.6-6,128.9 Bq/g dry weight, n = 14), collected in Tokyo, Nagano, Ibaraki, and Fukushima prefectures (1 m air dose rate: 0.11-21.4 μGy/h) after the Fukushima-Daiichi Nuclear Power Plant accident in 2012. The cesium concentration of nest materials increased significantly with the increment of the air dose rate, suggesting that air dose rate at nest sites provides an available indicator of the relative levels of nest contamination.