Predation Risk of the Shrub and Ground Nesting Passerines in a Disturbed Lowland Forest of Central Taiwan 台灣中部低海拔森林灌叢巢與地面巢 燕雀目鳥種的天敵掠食風險 陳宛均 李培芬 國立台灣大學生態學與演化生物學研究所 Introduction Methods Results and Discussion Conclusion Ground Competing modelsAIC c ΔAIC c wiwi nest height + concealment + camouflage + nest cover nest height + concealment + min camouflage + min nest cover + 4 vegetation cover tree density + nest height + concealment + min camouflage + min nest cover + 8 vegetation cover tree density + nest height + concealment + camouflage + nest cover + 8 vegetation cover AvianMammalSnakeMonkey χ2χ2 pχ2χ2 pχ2χ2 pχ2χ2 p Nest height ﹡ Concealment Camouflage Vegetation cover Relative Factors Factors Effects of Predators Timing of predators arrive 129 shrub nests (32 successful nests, 1,443 observation days) 56 ground nests (25 successful nests, 790 observation days). Daily survival rate of shrub nests (93.3%) was lower than ground nests (96.1%, p <0.001**). March, 2006 – April, 2007 in in Huben Village, Yunlin County Searched, monitored and 24 hrs recorded seven species of birds nests Shrub : 繡眼畫眉 (Alcippe morrisonia) 、白環鸚嘴鵯 (Spizixos semitorques) 、黑枕藍鶲 (Hypothymis azurea) 、白頭翁 (Pycnonotus sinensis) Ground : 八色鳥 (Pitta nympha) 、頭烏線 (Alcippe runnea) 、 小彎嘴畫眉 (Pomatorhinus ruficollis) Data analysis Logistic regression collocate characteristic factors model selection ： Akaike's information criteria (AIC) Kruskal-Wallis test fates of nests (1) success (2) fail indirect evidence direct evidence daily predation rate (Mayfield estimator) nest measurements Characterize of nest nest height substrate height substrate health slope camouflage nest cover nest concealment Microhabitat tree count → basal area → density of tree vegetation cover ＋ Predation is a primary cause of nest failure for nesting songbirds. Birds are excepted to select a safe nest-site to avoid predators. Dominant nest predators may different among nest sites, habitats, and the role of these predators may vary with time or ecological condition at multiple spatial scale. The approach of this study was to determine (1) predation risks of ground and shrub nests, and (2) relationship of nest characteristics and predators. Monkey were the individual predators in Taiwan. Nest predation risks by snakes were significantly higher in tropical and subtropical region than in temperate region. The nest-site characteristics were relative with predation events, but the exact interaction were unknown. Each type of predators searched for prey in a different manner.  auditory cues  visual cues  olfactory cues  depend on bird parental activity The safety nest sites depended somehow on the composition of the nest predators in the area where birds lived. Avian 樹鵲 (E=1, Y=1) 、筒鳥 (Y=1) 、大冠鷲 (Y=1) 、 鳳頭蒼鷹 (Y=3, P=2) 、不知名鳥 (Y=3) Snake 大頭蛇 (E=10, Y=2) 、南蛇 (E=4) 、茶斑蛇 (Y=1) 、赤背松柏根 (E=4, Y=2) 、紅斑蛇 (Y=1) 、錦蛇 (Y=1) 、臭青公 (E=1) 、龜殼花 (Y=4, P=1) 、不知名蛇 (E=40, Y=16) Monkey 台灣獼猴 (E=7,Y=5) Mammal 鼬獾 (E=2) 、白鼻心 (Y=1) 、食蟹獴 (Y=2) 、 刺鼠 (E=1, Y=1) 、不知名哺乳類 (E=3, Y=2) Ant (E=3, Y=3) E: egg, Y: young, P: bird parent Predator species