雲林大白鷺(Ardea alba)幼鳥的播遷模式與棲地選擇

大白鷺(Ardea alba)自2004年正式在台灣發現有夏候鳥繁殖的紀錄，但大白鷺幼鳥在台灣的播遷模式與棲地利用情況尚未有人探究。本研究在2019年5-6月雲林口湖的鷺鷥林捕捉7隻大白鷺幼鳥，並裝設衛星發報器，個體追蹤期間從67至368天不等，設定每隔4小時定位一次，個體的追蹤點位數從461至2219不等。追蹤個體一隻播遷235.4 km至新北淡水後斷訊，斷訊的還包含一隻播遷49.3 km至台南六甲。一隻播遷24.3 km至嘉義太保死亡，一隻留在雲林口湖死亡，剩下三隻存活個體皆留在雲林口湖，距離不超過10 km，大白鷺幼鳥離巢後每日活動距離為2.77±2.07km。本研究利用最小多邊型法(MCP)、核密度估計法(KDE)與自相關核密度估計法(AKDE)三種方法分析活動範圍，活動範圍面積MCP100%為15.73±12.15km2；KDE95%為13.00±10.36km2；AKDE95%為16.19±14.13km2，本研究以Manly-Chesson選擇指數分析大白鷺幼鳥棲地選擇，在五種覓食的棲地類型：水產養殖、濕地、其他水體、旱田與水田皆無偏好或趨避。

關鍵字

大白鷺；播遷；棲地選擇

並列摘要

First breeding record of Great egret (Ardea alba) was first recorded in 2004 in Taiwan. But the natal dispersal and habitat of the egret in Yunlin remains unknown. I banded and satellite-tracked seven great egret juveniles in May and June of 2019 in Shuilin. The solar satellite tags were set up with a time interval of 4-hour location fix. These birds were tracked from 67 to 368 days during the study period, with a total of 461 to 2219 location fixes. One individual dispersed 235.4 km to Tamsui, New Taipei and lost it signal; another one which also lost contact dispersed 49.3km to Liujia, Tainan. Two birds were dead before the end of the study; one dispersed 24.3 km to Taibao, Chiayi, and the other bird stayed at Kouhu, Yunlin. The remaining three birds stayed at Kouhu, Yunlin and didn’t disperse more than 10 km. The average movement distance of all great egret juveniles per day is 2.77±2.07km. We used minimum convex polygon (MCP), kernel density estimation (KDE) and autocorrelation kernel density estimation (AKDE) to estimate home ranges. The MCP100% home range area is 15.73±12.15km2. While KDE95% is 13.00±10.36km2 .And AKDE95% is 16.19±14.13km2. I use Manly-Chesson's Index to analyze the habitat selection of juvenile great egret in Aquaculture farm, wetland, other water bodies, dryland farm and paddy field. They shows no significant preference or avoidance to these habitats.