彩鷸（Rostratula benghalensis benghalensis）在宜蘭休耕田中的巢位選擇

Nest-site Selection of the Greater Painted Snipe (Rostratula benghalensis benghalensis) in Fallow Fields of I-Lan, Taiwan

巢位品質常會影響鳥類的繁殖成功與適存度。對在溼地中的地面繁殖的鳥，植物結構可能會影響掠食壓力，而水深則關乎巢會不會被水淹沒，所以可能是影響其巢位選擇的重要因子。我們以宜蘭深溝地區含水的休耕田為研究地點，檢視前述兩個因子對在當地繁殖的彩鷸之巢位選擇是否有影響。合計共在樣區中找到17個彩鷸的巢，並且在巢的附近選取隨機點測量環境狀況。透過成對檢驗，我們發現繁殖鳥較傾向於將巢築在植物覆蓋度高且水深較淺的地方，但營巢點的植物高度和隨機點間則沒有顯著差異。本研究共發現有五個巢因為被水淹沒或被掠食而失敗。彩鷸偏好在水位較淺處築巢，可能是為了要減少巢被水淹沒的機率；偏好植物覆蓋度高的位置築巢，則可能是為了因應掠食壓力。

Nest site quality often affects nest success and the fitness of avian breeders. Vegetation structure and water depth are possible factors evaluated in nest-site selection by ground nesting birds in wetlands. Vegetation structure may affect the predation risk, and water depth is linked to the possibility of being flooded. We examined these two factors in the nest site selection of a wetland bird, the Greater Painted Snipe (Rostratula benghalensis benghalensis), in I-Lan, Taiwan. We found 17 Greater Painted Snipe nests in wet fallow fields. By paired comparisons, we found the breeders tended to nest on sites with higher vegetation coverage and lower water depth than random sites. No significant difference was found in the vegetation height between the nest sites and the paired random sites. Five nests failed to hatch due to flooding or predation. The preference for nest sites with low water depth may be an effort to avoid being flooded and the preference for dense vegetation coverage at nest sites may be a response to predation risk.