The Japan Meteorological Agency (JMA) has been conducting phenological observations of not only plants but also animals throughout Japan for 68 years, but in 2021, the Agency discontinued all observations targeting animals. Sixty percent of these phenological observations targeting animals were to record animal sounds. The day of the year when an animal first sounds is also a signal for the start of breeding, and the timing of the start of such breeding is strongly influenced by climate change. Therefore, by continuing such observations, we can assess the effects of climate change, which can also be used to make mitigation and adaptation measures for climate change impacts. In recent years, passive acoustic monitoring (PAM) has grown rapidly in ecological and environmental research. At the same time, citizen science, in which non-specialists participate in environmental monitoring, is also growing rapidly. In this presentation, we introduce a case study in Toyama City that integrates the above two approaches. In the summer of 2024, we conducted observations of the first cicada calls for children at two elementary schools in the vicinity of the Toyama Meteorological Observatory of JMA. For the purpose of objectively evaluating the results of these observations, a PAM was conducted using an automatic recording device. Five species of cicadas were targeted. As a result, the following were found: 1) some children were able to capture the first calls of cicadas relatively accurately, but many children were slow to detect the first calls; 2) many children were likely to recognize the calls of cicada species in a confused manner; 3) PAM was able to accurately record the first calls of each cicada species, and it would be useful for predicting when and where first calls are likely to occur.