鸕鶿生態習性調查研究
一、研究緣起
金門位居東亞候鳥遷移路徑要點，候鳥資源豐富。其中數量龐大的鸕鶿（Phalacrocorax carbo）是最引起人們注意的過境鳥類，近年來在大小金門之越冬鸕鶿最大數量皆在5000隻以上。其龐大族群在晨昏進出的壯觀奇景，對賞鳥者與一般民眾都是相當難以忘懷的經驗，鸕鶿因此成為金門發展生態旅遊的一個重要主角。為深入研究金門地區鸕鶿渡冬族群的生態習性，本研究於民國94年3月至94年12 月間進行野外調查，以（1）估算鸕鶿在金門之族群數量變化，（2）探討鸕鶿之活動範圍及日行為模式，及（3）了解鸕鶿之覓食行為。
二、研究方法與過程
本研究於鸕鶿出現期間，每月至少進行二次金門鸕鶿族群之全面計數，計數方法為至各已知夜棲地進行直接計數。另外本研究以持續集中觀察方式，紀錄慈湖及太湖夜棲地鸕鶿族群之活動範圍、日行為模式、及覓食行為。
三、重要研究發現
（1）金門之鸕鶿度冬族群，很有可能是於中國華北、東北、及西伯利亞等地繁殖。於秋季分批自繁殖地至金門度冬，途中應有一至三個月的時間停留在遷移路線上的適合棲地。
（2）於金門內陸水域行個體覓食之鸕鶿，其活動範圍並不大，主要活動於其夜棲地及緊鄰夜棲地之水域。
（3）於金門周邊海域行群體覓食之鸕鶿，其活動範圍相當大，可飛至離夜棲地10-20公里外之地區。
（4）鸕鶿群體離開慈湖夜棲地之時間並不固定，主要集中6:30至9:30之間，而且鸕鶿可能避免於接近滿潮時群體離開慈湖。
（5）於內陸水域行個體覓食之鸕鶿，潛水持續時間平均為每次18.25秒，時間大多介於5秒至30秒之間。每次潛水有3.16 %之成功覓食比例。
（6）鸕鶿群體覓食分為圍旋式及履帶式二種方式。圍旋式群體覓食出現於寬廣之海域，履帶式群體覓食則多出現於鄰近岸邊之水域。
（7）太湖夜棲地之鸕鶿族群，覓食魚種主要為吳郭魚。慈湖夜棲地之鸕鶿族群，覓食魚種應主要為冬季集體迴游之鯔科魚類。
四、主要建議事項
中長期建議：
（1）金門之鸕鶿夜棲地均在國家公園管轄範圍之內，保護狀況良好。未來應持續保護其夜棲地不受破壞，並且控制對夜棲地之人為干擾。
（2）金門之鸕鶿度冬族群很有可能來自或飛經禽流感疫區，未來應該加強對鸕鶿及其他水禽之遷移研究，並持續進行金門國家公園之環境長期監測。
（3）協調有關單位，持續對金門水禽糞便之病毒檢測。
立即可行建議：
（1）禽流感病毒由野鳥傳至金門地區家禽之機會應該非常低，但應避免野鳥直接傳染人類之可能。目前金門國家公園管理處禁止一般人士進入慈湖鸕鶿夜棲地，同時也停止非保育類野鳥之救傷業務。這些禁止項目在明年夏季之前應該持續進行。
（2）一般之賞鳥活動並沒有感染禽流感之虞，未來沒有加以管制之必要，應宣導民眾對禽流感之正確認識。
（3）進入鳥類眾多區域之研究人員及工作人員，應採取適當之防護措施。
Abstract
Keywords：great cormorant, Phalacrocorax carbo, Kinmen, population trend, daily activity pattern, feeding behavior
A. Background
Kinmen is located on major bird migratory routes of East Asia. Among many migratory bird species recorded in Kinmen, great cormorant (Phalacrocorax carbo) is the species with large population size and special notions. In recent years, the wintering populations of great cormorant on Kinmen islands had more than 5000 individuals. The scene of tremendous flying flocks back to their roosting sites at dusks is unforgettable for bird watchers and ordinary people. Therefore, the wintering population of great cormorant has become a focal attraction of eco-tourism in Kinmen. In order to have a better understanding on the ecological habits of wintering great cormorants in Kinmen, we conducted this study from March 2005 to December 2005. The objectives of this study were to: (1) estimate the temporal trend of great cormorant population size on Kinmen Islands, (2) investigate the daily movement and daily activity pattern of great cormorant, (3) study the foraging behavior of great cormorant.
B. Methods
Total counts of cormorant individuals were conducted at least twice a month in the five roosting sites in Kinmen. The daily movement, daily activity pattern, and foraging behavior of cormorant were studies by focal sampling.
C. Major findings
(1) The breeding grounds of the wintering great cormorant populations in Kinmen are highly likely located in Siberia and the Northern and Northeastern parts of China. On their trips from breeding grounds to Kinmen, they should stop at suitable habitats on their migratory routes for about 1-3 months.
(2) The daily range of cormorants that foraging individually in lakes was mainly limited to their roosting sites and nearby waters.
(3) The cormorants that foraging on sea had a wide range of movement and might reach 10 - 20 km away from their roosting site.
(4) The depart times of great cormorants foraging groups from their Tzi Lake roosting site were mainly between 6:30 and 9:30. The foraging groups might avoid departing their roosting site at the flow of sea tide.
(5) The average duration of diving bouts for the lake-foraging cormorants was 18.25 sec, mostly diving bouts were between 5 sec and 30 sec. The success foraging rate of each diving bout was 3.16%.
(6) The great cormorants in Kinmen adapted two distinct social foraging tactics: “wheeling foraging” and “whirling foraging”, which were used in coastal water and open sea respectively.
(7) Tilapia spp. are the main foraging species of the cormorants that fish in the lakes of Kinmen. The cormorants that fishes in sea mainly foraged on species of Mugilidae.
D. Recommendations
(1) The roosting sites of great cormorants were all located within the boundary of Kinmen National Park and under well protection. The national park headquarter should continue its protection of and reduce disturbance to the roosting sites.
(2) The wintering great cormorants in Kinmen might come from or stop by infested areas of avian influenza in East Asia. Monitoring its population health and studying their migration routes are in high demand for successful prevention measures of avian influenza.
(3) Sampling and monitoring of avian influenza virus in bird droppings should be continued.
(4) The national park headquarter should continue to isolate the Tzi Lake roosting site of great cormorants and stop care of injured wild birds before next summer.
(5) Bird watching should have no risk of having avian influenza. There is a need to educate the local communities.
(6) Researchers and workers should undertake appropriate measures to prevent avian influenza.
金門位居東亞候鳥遷移路徑要點，候鳥資源豐富。其中數量龐大的鸕鶿（Phalacrocorax carbo）是最引起人們注意的過境鳥類，近年來在大小金門之越冬鸕鶿最大數量皆在5000隻以上。其龐大族群在晨昏進出的壯觀奇景，對賞鳥者與一般民眾都是相當難以忘懷的經驗，鸕鶿因此成為金門發展生態旅遊的一個重要主角。為深入研究金門地區鸕鶿渡冬族群的生態習性，本研究於民國94年3月至94年12 月間進行野外調查，以（1）估算鸕鶿在金門之族群數量變化，（2）探討鸕鶿之活動範圍及日行為模式，及（3）了解鸕鶿之覓食行為。
二、研究方法與過程
本研究於鸕鶿出現期間，每月至少進行二次金門鸕鶿族群之全面計數，計數方法為至各已知夜棲地進行直接計數。另外本研究以持續集中觀察方式，紀錄慈湖及太湖夜棲地鸕鶿族群之活動範圍、日行為模式、及覓食行為。
三、重要研究發現
（1）金門之鸕鶿度冬族群，很有可能是於中國華北、東北、及西伯利亞等地繁殖。於秋季分批自繁殖地至金門度冬，途中應有一至三個月的時間停留在遷移路線上的適合棲地。
（2）於金門內陸水域行個體覓食之鸕鶿，其活動範圍並不大，主要活動於其夜棲地及緊鄰夜棲地之水域。
（3）於金門周邊海域行群體覓食之鸕鶿，其活動範圍相當大，可飛至離夜棲地10-20公里外之地區。
（4）鸕鶿群體離開慈湖夜棲地之時間並不固定，主要集中6:30至9:30之間，而且鸕鶿可能避免於接近滿潮時群體離開慈湖。
（5）於內陸水域行個體覓食之鸕鶿，潛水持續時間平均為每次18.25秒，時間大多介於5秒至30秒之間。每次潛水有3.16 %之成功覓食比例。
（6）鸕鶿群體覓食分為圍旋式及履帶式二種方式。圍旋式群體覓食出現於寬廣之海域，履帶式群體覓食則多出現於鄰近岸邊之水域。
（7）太湖夜棲地之鸕鶿族群，覓食魚種主要為吳郭魚。慈湖夜棲地之鸕鶿族群，覓食魚種應主要為冬季集體迴游之鯔科魚類。
四、主要建議事項
中長期建議：
（1）金門之鸕鶿夜棲地均在國家公園管轄範圍之內，保護狀況良好。未來應持續保護其夜棲地不受破壞，並且控制對夜棲地之人為干擾。
（2）金門之鸕鶿度冬族群很有可能來自或飛經禽流感疫區，未來應該加強對鸕鶿及其他水禽之遷移研究，並持續進行金門國家公園之環境長期監測。
（3）協調有關單位，持續對金門水禽糞便之病毒檢測。
立即可行建議：
（1）禽流感病毒由野鳥傳至金門地區家禽之機會應該非常低，但應避免野鳥直接傳染人類之可能。目前金門國家公園管理處禁止一般人士進入慈湖鸕鶿夜棲地，同時也停止非保育類野鳥之救傷業務。這些禁止項目在明年夏季之前應該持續進行。
（2）一般之賞鳥活動並沒有感染禽流感之虞，未來沒有加以管制之必要，應宣導民眾對禽流感之正確認識。
（3）進入鳥類眾多區域之研究人員及工作人員，應採取適當之防護措施。
Abstract
Keywords：great cormorant, Phalacrocorax carbo, Kinmen, population trend, daily activity pattern, feeding behavior
A. Background
Kinmen is located on major bird migratory routes of East Asia. Among many migratory bird species recorded in Kinmen, great cormorant (Phalacrocorax carbo) is the species with large population size and special notions. In recent years, the wintering populations of great cormorant on Kinmen islands had more than 5000 individuals. The scene of tremendous flying flocks back to their roosting sites at dusks is unforgettable for bird watchers and ordinary people. Therefore, the wintering population of great cormorant has become a focal attraction of eco-tourism in Kinmen. In order to have a better understanding on the ecological habits of wintering great cormorants in Kinmen, we conducted this study from March 2005 to December 2005. The objectives of this study were to: (1) estimate the temporal trend of great cormorant population size on Kinmen Islands, (2) investigate the daily movement and daily activity pattern of great cormorant, (3) study the foraging behavior of great cormorant.
B. Methods
Total counts of cormorant individuals were conducted at least twice a month in the five roosting sites in Kinmen. The daily movement, daily activity pattern, and foraging behavior of cormorant were studies by focal sampling.
C. Major findings
(1) The breeding grounds of the wintering great cormorant populations in Kinmen are highly likely located in Siberia and the Northern and Northeastern parts of China. On their trips from breeding grounds to Kinmen, they should stop at suitable habitats on their migratory routes for about 1-3 months.
(2) The daily range of cormorants that foraging individually in lakes was mainly limited to their roosting sites and nearby waters.
(3) The cormorants that foraging on sea had a wide range of movement and might reach 10 - 20 km away from their roosting site.
(4) The depart times of great cormorants foraging groups from their Tzi Lake roosting site were mainly between 6:30 and 9:30. The foraging groups might avoid departing their roosting site at the flow of sea tide.
(5) The average duration of diving bouts for the lake-foraging cormorants was 18.25 sec, mostly diving bouts were between 5 sec and 30 sec. The success foraging rate of each diving bout was 3.16%.
(6) The great cormorants in Kinmen adapted two distinct social foraging tactics: “wheeling foraging” and “whirling foraging”, which were used in coastal water and open sea respectively.
(7) Tilapia spp. are the main foraging species of the cormorants that fish in the lakes of Kinmen. The cormorants that fishes in sea mainly foraged on species of Mugilidae.
D. Recommendations
(1) The roosting sites of great cormorants were all located within the boundary of Kinmen National Park and under well protection. The national park headquarter should continue its protection of and reduce disturbance to the roosting sites.
(2) The wintering great cormorants in Kinmen might come from or stop by infested areas of avian influenza in East Asia. Monitoring its population health and studying their migration routes are in high demand for successful prevention measures of avian influenza.
(3) Sampling and monitoring of avian influenza virus in bird droppings should be continued.
(4) The national park headquarter should continue to isolate the Tzi Lake roosting site of great cormorants and stop care of injured wild birds before next summer.
(5) Bird watching should have no risk of having avian influenza. There is a need to educate the local communities.
(6) Researchers and workers should undertake appropriate measures to prevent avian influenza.