Acoustic detections of birds using the SILIC in Yushan National Park, Taiwan

Study Extent

The study area was located in the Southern Area of YSNP, a typical montane ecosystem in central Taiwan. Six PAM stations were deployed between Meishan and Yako along the Southern Cross-Island Highway, with an elevation range from 1,264 m above sea level (MSC01) to 2,739 m (WK01). The longest distance between any two stations was around 11.4 km and the shortest distance was 500 m. The habitat types vary from lower (1,264 m) to higher (2,739 m) elevation, including sub-montane evergreen broad-leaved forests, montane evergreen broad-leaved cloud forests, montane mixed cloud forests, and upper-montane coniferous forests. 被動式聲學監測站設置於玉山國家公園南部園區，南部橫貫公路梅山至埡口沿線。玉山國家公園位於臺灣本島之中央地帶，面積廣達103,121公頃，地形以高山及河谷為主，3,000 公尺以上之地區約占全區面積 12.74 %，列名臺灣「百岳」之山峰共有 30 座，其中包括百岳之首的臺灣最高峰—玉山。目前已完成的6個樣站係沿南部橫貫公路架設，分別為梅山（MSC01，海拔1,264公尺）、中之關（ZZG01，海拔2,047公尺）、天池(下)（TT01，海拔2,303公尺）、天池(上)（TT02，海拔2,366公尺）、檜谷（KK01，海拔2,429公尺）及埡口林道（WK01，海拔2,739公尺），設置時間自2020起，預期進行無限期之長期監測。

Sampling

The Song Meter SM4 and Song Meter Mini made by Wildlife Acoustic Inc. were used as the autonomous recording units (ARUs) in this dataset. The ARUs were scheduled to record a 1-min recording every three minutes in stereo, 16-bit WAV format at a sampling rate of 44.1 kHz. The SILIC was used to detect animal vocalizations automatically in the recordings. The threshold of a confidence score was chose once the precision reached to 0.95 for each sound class. All the detections of each sound class with a confidence score no less than the threshold were treated as positives and archived in this dataset. 被動式聲學監測站為定時錄音，使用之錄音機為Wildlife Acoustic公司製造之Song Meter SM4及Song Meter Mini，設置參數為每錄製1分鐘休息2分鐘、雙聲道、取樣頻率44.1 KHz、位元深度16 bit，錄音資料儲存為PCM WAV檔格式。利用SILIC自動偵測音檔中之動物鳴叫聲，取精確率（Precision）為0.95的信賴分數（Confidence Score）作為閾值（Threshold），分數大或等於閾值的偵測結果視為陽性（positive，即認定該筆資料為目標聲音），陽性偵測結果彙整為本資料集。

Quality Control

The model version exp24 of the SILIC was used to detect animal vocalizations in this dataset (https://github.com/RedbirdTaiwan/silic). Seven sound classes were selected as follows and 150 random clips of each sound class were sampled to evaluate the performance including the precision and the recall. The threshold of a confidence score was chose once the precision reached to 0.95 for each sound class. All the detections of each sound class with a confidence score no less than the threshold were treated as positives. 本資料集使用SILIC exp24模型進行分析（ https://github.com/RedbirdTaiwan/silic ），目前已完成7種聲音之偵測，每種聲音隨機取150筆偵測結果進行精確率（Precision）與召回率（Recall）估算，取精確率（Precision）為0.95的信賴分數（Confidence Score）作為閾值（Threshold），分數大或等於閾值的偵測結果視為陽性（positive，即認定該筆資料為目標聲音）。 9 - 白耳畫眉 (Heterophasia auricularis) S-01: Threshold=0.54、Precision=0.95、Recall=0.53。 28 - 五色鳥 (Psilopogon nuchalis) S-01: Threshold=0.26、Precision=0.95、Recall=0.80。 122 - 黃胸藪眉 (Liocichla steerii) S-01: Threshold=0.73、Precision=0.95、Recall=0.48。 324 - 冠羽畫眉 (Yuhina brunneiceps) S-01: Threshold=0.71、Precision=0.95、Recall=0.55。 337 - 灰喉山椒 (Pericrocotus solaris) U-01: Threshold=0.57、Precision=0.95、Recall=0.72。 361 - 白尾鴝 (Myiomela leucura) S-01: Threshold=0.51、Precision=0.95、Recall=0.68。 471 - 巨嘴鴉 (Corvus macrorhynchos) C-01: Threshold=0.48、Precision=0.95、Recall=0.64。

Method steps

1. The Song Meter SM4 and Song Meter Mini made by Wildlife Acoustic Inc. were used as the autonomous recording units (ARUs) in the project. The ARUs were tied on trees around 1.5 m above the grounds and covered with sound-absorbing canopies. All ARUs were scheduled to record a one-min recording every three minutes in stereo, 16-bit WAV format at a sampling rate of 44.1 kHz. 被動式聲學監測站為定時錄音，使用之錄音機為Wildlife Acoustic公司製造之Song Meter SM4及Song Meter Mini，設置參數為每錄製1分鐘休息2分鐘、雙聲道、取樣頻率44.1 KHz、位元深度16 bit，錄音資料儲存為PCM WAV檔格式。
2. Memory cards storing acoustic data were replaced monthly and two copies of files were archived separately in local storages and Google Drive for data safety. 每月更換記憶卡及電池，錄音資料存放於電腦硬碟並備份於Google雲端硬碟。
3. The “exp24” model in SILIC was used to detect animal vocalizations automatically in the recordings and produced sound labels containing the information of filename, soundclass ID, start/end time and low/high frequency, and confidence score of each detected vocalizations. 錄製之聲景資料利用SILIC exp24版進行自動化分析，SILIC會自動偵測並標記音檔中動物鳴叫聲。
4. 150 random labels of each sound class were sampled to evaluate the performance metrics including the scores of precision and recall. 每種聲音隨機取150筆資料進行精確率（Precision）與召回率（Recall）估算。
5. The threshold of a confidence score was chosen once the precision reached to 0.95 for each sound class. All labels of each sound class with a confidence score no less than the threshold were treated as positives. 取精確率（Precision）為0.95的信賴分數（Confidence Score）作為閾值（Threshold），分數大或等於閾值的偵測結果視為陽性（positive，即認定該筆資料為目標聲音）。
6. To reduce storage requirements, we summarized the positive detections of the same species in the same recordings. For example, a single recording (i.e. an event) may be containing none, one or more species (i.e. occurrences), and each species may have vocalized one or more times (i.e. number of observations). 為減少資料量，將同錄音檔且同聲音編號之聲音進行數量加總，每筆含有動物叫聲的錄音檔為一筆調查活動（event），於錄音檔中的1種聲音視為１筆出現記錄（occurrence），觀測數量（number of observations）則為該錄音檔中該物種的鳴叫總次數。

The taxonomic coverage would increase with the version and precision of the SILIC which is used to detect vocalizations of vertebrates automatically in the soundscape recordings. 本資料集係使用SILIC自動偵測聲景音檔中之脊椎動物鳴叫聲，涵蓋物種數將隨SILIC的可偵測物種數及精確率不定期增加。

1. Liocichla steerii
   common name: 黃胸藪眉 rank: species
2. Psilopogon nuchalis
   common name: 五色鳥 rank: species
3. Corvus macrorhynchos
   common name: 巨嘴鴉 rank: species
4. Pericrocotus solaris
   common name: 灰喉山椒 rank: species
5. Heterophasia auricularis
   common name: 白耳畫眉 rank: species
6. Yuhina brunneiceps
   common name: 冠羽畫眉 rank: species
7. Myiomela leucura
   common name: 白尾鴝 rank: species

Six PAM stations were deployed between Meishan and Yako along the Southern Cross-Island Highway, with an elevation range from 1,264 m above sea level (MSC01) to 2,739 m (WK01). 6座被動式聲學監測站設置於玉山國家公園南部園區，南部橫貫公路梅山至埡口沿線。6個樣站係沿南部橫貫公路架設，海拔範圍介於1,264至2,739 公尺。