Most male anuran species in Japan vocalize to attract females for breeding. The calling surveys by their vocalization are performed to monitor anuran populations in each place.

We conducted sound monitoring of anurans in Higashiakasawa town, Toyohashi city, Aichi prefecture, central Japan from the beginning of April 2010 to the end of October 2010. We chose a rice field which has water only during the irrigation period as a monitoring site. We installed a waterproof digital voice recorder at each site and recorded the surrounding　sounds every day for 10 minutes from 20:00.

This investigation, confirmed that the study area was inhabited by 5 anuran species, namely, Hyla japonica, Rhacophorus schlegelii, Rana nigromaculata, Rana rugosa, Fejervarya limnocharis. And we examined how the calling activity of 5 sympatric anuran species varies in response to the exogenous environmental factors such as the meteorological condition during a full breeding season.