Singing activities of birds in the early spring are mainly controlled by the photoperiod and other environmental factors such as temperature, food, and rainfall. In this study, we monitored the vocal activity of a forest bird community in the Shan-Ping Forest Ecological Garden, southern Taiwan, to explore the influence of ambient temperature on the vocal behavior of birds. An acous tic monitoring system was set up to record bird sounds throughout the morning hours in March of 2011 and 2012, and the air temperature was recorded on the hour by a data logger. Recorded soundscape files were sampled, transcribed, and analyzed. Results showed that both the number of bird species and vocal activity detected in 10-min intervals sampled from 6 morning hours were positively correlated with the air temperature in both years. At the species level, the relationship between vocal activity and air temperature was found to be significant for 6 of 16 common resident species. Furthermore, air temperature at 10:00 or 11:00 appeared to be a better predictor of vocal activities of birds in the study plot than those measured from 06:00 to 09:00. This study illustrated that the vocal activity of a forest bird community was strongly influenced by air temperature and closely fluctuated with the dynamics of cold fronts. We propose that this relationship could be developed into a bioassay to examine the influence of global warming on spring singing of birds through autonomous recording.