臺北市鳳頭蒼鷹之巢位選擇

鳳頭蒼鷹（Accipiter trivirgatus）是臺灣目前唯一從郊區自然棲地拓展到都市地區繁殖的日行性猛禽。為瞭解鳳頭蒼鷹於都市繁殖之棲地特徵，我們以徒步調查的方式尋找臺北市區公園、校園及行道樹上之鷹巢，記錄繁殖概況並測量繁殖巢樹、巢樹所在綠地和巨棲地等3種尺度下的棲地變因。另在無繁殖紀錄的公園，選定虛擬巢樹進行相同測量，做為對照組。於2020年和2021年分別調查88和107處樣點，並記錄10和12巢的繁殖巢位。研究結果顯示，在巨棲地尺度上，臺北市鳳頭蒼鷹繁殖巢位通常具有較大面積的樹林覆蓋，半徑300與150 m範圍內的樹林面積均是具影響力的預測因子。在鳳頭蒼鷹選擇築巢的綠地，其巢位的都市化程度較低（人造鋪面比例較低、離道路和建物的距離較遠），並且其至穩定水源的距離較近。由巢樹的特徵來看，相對於對照組的虛擬巢樹，鳳頭蒼鷹築巢巢樹的胸高直徑及樹冠直徑較小。我們的研究結果認為，在都市林經營管理上，營造或維持大面積的樹林，並且環境中具小型可利用的水源，將可提供鳳頭蒼鷹的棲息及繁殖。

關鍵字

鳳頭蒼鷹；猛禽；巨棲地；樹林面積；都市化

並列摘要

The Crested Goshawk (Accipiter trivirgatus) is currently the only diurnal raptor in Taiwan that is expanding its breeding range from natural and rural habitats into urbanized areas. In order to understand the characteristics of the breeding habitat of Crested Goshawks in the city, we searched for their nests in trees of parks, campuses, and streets in the Taipei urban area by way of walking surveys, recorded the reproductive stage, and measured features at nest trees, the green space where the nest tree was located, and macro habitat levels. For parks with no breeding records, virtual nest trees were selected for the same measurements as a control group for comparison. In 2020 and 2021, 88 and 107 sampling sites were surveyed, and 10 and 12 Crested Goshawk nests were recorded, respectively. Results of the study showed that on the macro habitat level, Crested Goshawk nesting habitats in urban Taipei usually included large areas of forest cover, and forested areas within radii of 300 and 150 m were influential predictors of Goshawk nest site selection. In green spaces where Crested Goshawks nested, the nest sites were less urbanized (with lower coverage of man-made pavement and greater distances from roads and buildings) and closer to stable water sources. From the characteristics of the nest trees, compared to virtual nest trees of the control group, the diameter at breast height and crown diameter of nest trees of Crested Goshawk were relatively smaller. Our findings suggest that in urban forest management, creating or maintaining large areas of forests with small, available water sources in the environment will provide habitats for breeding Crested Goshawks.

並列關鍵字

Accipiter trivirgatus ； raptor ； macro habitat ； forest area ； urbanization

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