金門栗喉蜂虎營巢棲地復育效應與棲地選擇模式

Abstract

壹、栗喉蜂虎營巢棲地復育效應 栗喉蜂虎（Merops philipinnus）為5-8月到金門生殖的夏候鳥。本研究將舊有營巢坡面整理，測試坡面上植被覆蓋及舊洞造成的營巢空間不足，是否為栗喉蜂虎選擇營巢坡面的重要因子，並評估整理試驗對生殖的影響。舊有營巢坡面的整理組和對照組在環境及坡面物理性質上沒有差異，只有整理組的坡面植被覆蓋度（0%）比對照組（34.5%）低；在窩卵數、孵化率及巢成功率上沒有顯著差異；但坡面整理後營巢密度增加，且營巢數也隨著可營巢空間愈大而增加，顯示坡面整理對栗喉蜂虎生殖成功雖沒有影響，但確能增加生殖族群數量。以無線電追蹤分析4隻栗喉蜂虎在育雛期覓食棲地的選擇。發現平均覓食距離為170 .4m，最遠距離為673.3 m；平均覓食活動範圍面積為23.3 ha，蜂虎偏好於草生地及農耕地覓食、活動，可能和食物資源分布有關。 貳、栗喉蜂虎營巢棲地選擇模式 本研究以金門島夏候鳥栗喉蜂虎為研究對象，分別探討坡面特性及地景因子對栗喉蜂虎營巢棲地選擇的影響，並建立栗喉蜂虎營巢棲地的選擇模式，以了解栗喉蜂虎營巢棲地需求。在棲地坡面特性分結果顯示，栗喉蜂虎的營巢坡面大致朝北至東方，可能和此方位之坡向不易受盛行西南風及太陽輻射的影響，巢洞溫濕度較穩定有關。利用群集分析分別產生不同坡面特性及地景類型，再以逐步判別分析探討營巢地及無營巢地之間的差異。在不同地景類型下產生的模式顯示，栗喉蜂虎偏好坡前植被低矮、土質為砂性土、坡面面積大的裸露坡面營巢，推測這樣的環境因容易偵測天敵，且具有較多營巢空間。而不同坡面特性類型則無法產生判別式。全島營巢地在距營巢地200 m以內的邊緣密度及水域面積比例顯著比無巢地高，可能表示此地食物資源的多樣性及豐富度高，可吸引蜂虎營巢。本研究進行前以相關研究規劃出調查項目，並設計調查表單，能提供未來栗喉蜂虎營巢地調查時的參考，而研究結果也將提未來栗喉蜂虎棲地經營管理之參考。

Chapter 1 Blue-tailed Bee-eaters (Merops philipinnus) are summer migrant to Kinmen Island. They breed from May to August. I cleaned the vegetation and old nest holes on the slope of used breeding colonies to test if these two are important factors for bee-eaters to abandon old colony. I also evaluated the effects of cleaning (treatment) on bee-eaters’ breeding performance comparing with no cleaning (control). There was no significant difference in terms of environment and slope physical characteristics except for a lower vegetation cover for the treatment (0 %) than control (34.5%) groups. There was also no significant difference in clutch size, hatching rate and breeding success rate between these two groups. However, with the increased of slope area after cleaning, the nest holes density increased and there was a positive relationship between number of nest holes and available nesting space. Therefore, cleaning might not affect the bee-eaters’ breeding success, but it could increase the breeding population size. With the radio-telemetry on four adult bee-eaters, I found the average feeding distance during the nestling period was 170.4 m with the longest distance as 673.3 m and the average feeding area was 23.3 ha. Bee-eaters preferred to feed on grassland and agriculture field, which might be related to the distribution of food resources. Chapter 2 The Blue-tailed Bee-eater (Merops philipinnus) is summer breeder in Kinmen. The purpose of this research was trying to identify what factors including bank features and landscape features influencing breeding habitat selection of bee-eaters. I found bee-eaters preferred to nest on bank oriented from North to East, presumed there was stable temperature and humidity condition in burrows. Different kinds of bank feature types and landscape type were classified by cluster analysis, then separated into nest-site and non-nest-site by discriminant analysis. In bank feature types, bee-eaters preferred to use high and wide sandy soil bank without high vegetation in front, implying that bee-eaters preferred to nest on big slope providing more nesting space, and environment being easy to detect predators. Comparing all the nest-site with the non-nest-site on the island, in radius 200 m of colony, bee-eaters preferred to breed in the environment with high landscape heterogeneity and more water area, meaning that high insect prey availability in bee-eater’s breeding habitat. I also designed a habitat investigation checklist which could be used for future bee-eater studies.