ESM 3: Peak frequency SNRs for tutor songs from Acoustic adaptation to city noise through vocal learning by a songbird

The signal-to-noise ratio (SNR) of the peak frequency for each 5ms of sound in each tutor song and which of these time periods the SNR was above the critical ratio in noise

针对每一段导师鸣曲（tutor song）内每5毫秒的声音片段，提取其峰值频率对应的信噪比（SNR），并统计上述时间片段中，哪些在噪声环境下的信噪比高于临界比率。