YIN-Bird: Improved Pitch Tracking for Bird Vocalisations

Pitch is an important property of birdsong. Accurate and automatic tracking of pitch for large numbers of recordings would be useful for automatic analysis of birdsong. Currently, pitch trackers such as YIN can work with carefully tuned parameters but the characteristics of birdsong mean those optimal parameters can change quickly even within a single song. This paper presents YIN-bird, a modified version of YIN which exploits spectrogram properties to automatically set a minimum fundamental frequency parameter for YIN. This parameter is continuously updated without user intervention. A ground truth dataset of synthetic birdsong with known fundamental frequency is generated for evaluation of YIN-bird. Listener tests from expert birders described the synthetic samples as “sounding like original & can hardly tell it is synthetic”. Gross pitch error on whistles and trills were reduced by up to 4%. An analysis of nasal sounds shows the challenge in accurate pitch tracking for this syllable type.