利用紅外線自動相機進行鳥巢箱之天敵監測

Use of infrared camera traps to monitor predators of nest boxes

本研究於2016年5月－8月及2017年4月－6月於奧萬大森林遊樂區內以紅外線自動相機進行鳥巢箱天敵之監測，並搭配人力探巢來了解各巢箱之使用與繁殖情形。期間共使用自動相機監測31個巢箱，拍攝到的天敵種類有臺灣獼猴（Macaca cyclopis）、臺灣藍鵲（Urocissa caerulea）、赤腹松鼠（Callosciurus erythraeus thaiwanensis）、條紋松鼠（Tamiops maritimus formosanus）及無法辨識的鼠類。拍攝到的影像中以臺灣獼猴出現頻度最高，並有記錄到4筆臺灣獼猴明確侵擾與破壞巢箱的影像；其次為赤腹松鼠，並記錄到2筆侵擾與破壞巢箱的影像，臺灣藍鵲則有一筆侵擾巢箱的影像。在此兩次繁殖季中，共記錄到144個繁殖巢，繁殖成功的巢共34個，失敗的巢共110個。整合繁殖失敗原因，蛋／幼雛不明原因死亡或消失占40％（n=44）、判斷為臺灣獼猴掠食占23.6％（n=26）、蛇類掠食占22.7％（n=25）、親鳥棄巢占12.7％（n=14）及經自動相機拍攝確認為赤腹松鼠掠食占0.9％（n=1）。臺灣獼猴為本研究中透過自動相機之監測結果發現造成使用巢箱鳥類繁殖失敗較主要的天敵，若欲減少臺灣獼猴對巢箱造成物理上的破壞，建議可在巢箱結構上進行補強。後續可持續以紅外線自動相機記錄奧萬大森林遊樂區天敵侵擾巢箱狀況，並以較密集的人力探巢方式輔助記錄，或嘗試將自動相機設定為縮時拍攝模式，以提高變溫動物天敵的偵測率並增加辨識實際掠食巢箱的天敵物種。 We used infrared camera traps to monitor predators of nest boxes from May to August in 2016 and April to June in 2017 in Aowanda National Forest Recreation Area and checked the breeding stage of each nest box once a week. We recorded the following species of nest predators: Formosan macaque (Macaca cyclopis), Taiwan blue magpie (Urocissa caerulea), Red-bellied squirrel (Callosciurus erythraeus thaiwanensis), Formosan striped squirrel (Tamiops maritimus formosanus) and rodents (Muridae). Among the recording images, the occurrence index of Formosan macaque was the highest, and there were 4 records of Formosan macaques which invaded and damaged the nest boxes; the second most frequent species was the red-bellied squirrel, and there were 2 records of red-bellied squirrel which invaded and damaged the nest boxes, and there was one record of the Taiwan blue magpie invaded a nest box. We monitored 144 nests, of which 34 nests were identified as breeding success and 110 as failure during the two breeding seasons. The factors which caused breeding failure included (1) eggs/chicks disappeared or died for no obvious reasons (40%, n = 44), (2) predation by macaques (23.6%, n = 26), (3) predation by snakes (22.7%, n = 25), (4) nest abandonment (12.7%, n = 14) and (5) predation by red-bellied squirrels (0.9%, n = 1). Therefore, Formosan macaques were the main predator to the birds monitored in our study. In order to prevent Formosan macaque from damaging the nest box, it is necessary to strengthen the structure of the nest boxes. We will continue to use infrared camera traps and frequent nest boxes checks to monitor the breeding success of these birds which use nest boxes, and will set cameras to time-lapse photography mode to increase the detection rate of poikilothermal predators and confirm the actual predator species of nest boxes.