農業作業對屏東地區黑鳶(Milvus migrans)覓食活動的影響

衛星追蹤提升了物種大範圍棲地利用的研究效率，然而小尺度的環境變化與資源利用，仍需透過實地觀察去補足。本研究在2017年末與2018年初的繁殖季期間，在屏東地區以衛星追蹤資料配合實地觀察，選擇養殖池與旱田共六個覓食地，記錄黑鳶(Milvus migrans)覓食地農業作業、個體數、取食與共域猛禽。同時以2016年與2017年繁殖季的黑鳶衛星追蹤資料，呈現黑鳶覓食地與夜棲地的利用百分比。衛星追蹤結果顯示黑鳶在各主要覓食地利用上，會隨不同時期轉換，並傾向選擇與覓食地距離更近的夜棲地。實地觀察中，黑鳶數量在旱田翻耕時期會顯著增加，在養殖池的利用百分比則比起旱田更持續且穩定。一天中的覓食地數量高峰在10:00到15:00間。黑鳶在魚塭的取食以死魚最多，皆佔98%以上，蝦池取食餌料與死蝦，旱田在翻耕時期有較多的取食紀錄，包含小型哺乳類、鳥類與不明屍肉。受範圍與食物種類影響，旱田的取食紀錄比起養殖池更有難度。黑鳶在覓食地與其他猛禽共域時，彼此攻擊、掠奪等行為皆未出現，追逐則佔26%，最常見的是彼此沒有敵對行為，佔68%。本研究呈現了在屏東部分黑鳶族群對六個主要覓食地的利用狀況，並補充了衛星追蹤較缺乏的族群實地利用資訊，提供相關產業在黑鳶棲地經營管理的參考。

關鍵字

食腐者；機會主義者；實地觀察；養殖池；旱田；敵對；棲地經營管理

並列摘要

Satellite tracking has improved the research efficiency of large-scale habitat use of species. However, small-scale environmental change and resource use still need to be complemented by field observation. Satellite tracking and field observation were used to record the foraging activity of black kites (Milvus migrans) of six foraging sites, including culture ponds and dry fields in Pingtung. The numbers and diets of black kites with different agricultural operations, and the coexistence of black kites with other raptors were recorded during the breeding season in late 2017 and early 2018. The satellite-tracking data of breeding seasons of 2016 and 2017 showed that the usage rate of foraging sites and night-roosting sites of black kites will change over time. Also, black kites tended to choose night-roosting sites that are closer to their main foraging sites. In field observation, the number of black kites increased significantly on the ploughing day of dry fields, and the usage rate of culture ponds was more sustained and stable than that of dry fields. Daily peak of foraging activity was between 10:00 and 15:00. More than 98% of diet of black kite in the fish farm was dead fish while diet in the shrimp farm was shrimp bait and dead shrimp. The dry fields had more feeding records during the ploughing period, including rodents, birds and unknown corpses. Due to the range and diet, it is more difficult to record the diets of black kites in dry fields than in culture ponds. When black kites coexist with other raptors, neither aggression nor kleptoparasite had been recorded. Twenty-six percent of the events were “chasing,” while “no behavior” accounted for 68%. This study presents the use of the six main foraging sites in some part of black kite population in Pingtung. In addition, it provides some information for the management of black kite habitat in related industries.