I need to recognize just one bird. I am trying to compare the syllables extracted from the sound samples. As a result of the spectrogram function, the power spectral density is taken from the sound. They are 2 dimensional values. I like to compare this test signal with a known signal which is another 2 dimensional value. Could you please suggest what would be the best function to use for comparison. Please keep in mind that the syllable of the test bird could be time shifted or they closely match the original bird. I am attaching the sample spectrogram and its syllable extracted here after filtering..