都市黑冠麻鷺（Gorsachius melanolophus）巢位選擇

都市化為全球趨勢，聯合國預測2050年將有近70 %人口居住於都市，因而都市生態系的研究顯得益發重要。都市化同時創造新興生態系，也讓許多鳥類居住於此，臺灣的黑冠麻鷺（Gorsachius melanolophus）便是其中一例。本研究探討黑冠麻鷺在都市公園綠地中，快速成長的生存策略與影響巢位選擇因素。研究期間為2019年3-10月，在臺北市的大安森林公園、中正紀念堂、青年公園、臺灣大學校總區及二二八公園等5個樣區，調查黑冠麻鷺的巢位分布、繁殖表現、巢位及巢樹特徵，和巢位棲地利用情形。結果顯示，都市黑冠麻鷺整體孵化率及幼雛存活率皆大於90 %，繁殖成功率為95.74%，且繁殖季中有兩次繁殖高峰期。其巢位於具分岔且傾斜角度接近水平的枝條上，巢上覆蓋度至少有70 %，巢樹選擇偏好胸高及樹冠直徑較大者。黑冠麻鷺在樹冠下層築巢，且巢位下棲地多是人為活動環境的土地型態。都市化環境可使天敵不易接近，提高繁殖成功率，加上繁殖資源充足且生產力提升，均有利於在都市生存。築巢於平穩枝條且有利監測人為活動的位置，以隨時對干擾風險做出適當反應，是黑冠麻鷺可適應都市化環境的原因之一。本研究透過探討於都市中繁殖的黑冠麻鷺巢位選擇行為，期望能對都市生態系有更進一步的瞭解。

關鍵字

繁殖；公園綠地；棲地利用；人為活動環境

並列摘要

Urbanization is a global trend. The United Nations predicts that nearly 70% of the population will dwell in urban area in 2050, so studies of urban ecosystems becomes increasingly important. Also, Urbanization creates novel ecosystems, and lets many birds reside here. The Malayan night herons (Gorsachius melanolophus) in Taiwan is a good example. This study explored the survival strategies of the rapid growth and the factors affecting nest-site selection for Malayan night herons in urban park and green space. From March to October in 2019, we investigated the nest-site distribution, breeding performance, nest-site characteristics, nest tree characteristics, and nest-site habitat use of the Malayan night heron in 5 sampling areas, including Daan Forest Park, Chiang Kai-shek Memorial Hall, Youth Park, National Taiwan University Campus and 228 Peace Park in Taipei City. The results showed that the overall hatching rate and survival rate of chicks of the urban Malayan night herons were both over 90 %, the reproductive success was 95.74%, and there were two periods of breeding peak during the breeding season. The nests are located on branches with forks and the inclination is close to horizontal. The canopy coverage of the nests is at least 70 % and the nest trees are those with larger diameter at breast height and the crown width. The Malayan night herons build nests on lower crown, and the habitats under the nest-sites are mostly a land type with a human activity environment. The predators are not easy to access in the urbanized environment, which increases the reproductive success, coupled with sufficient breeding resources and increasing productivity, which is conducive to survive in urban. The Malayan night herons chose to nest on stable branches, where is also beneficial for them to monitor the potential human activities, which is one of the reasons why they can adapt to the urban environment. This study expects to have a better understanding of the urban ecosystem by exploring the nest-site selection behavior of the Malayan night heron breeding in urban area.