Predation Risk of the Shrub and Ground Nesting Passerines in a Disturbed Lowland Forest of Central Taiwan
Date Issued
2007
Date
2007
Author(s)
Chen, Wan-Jyun
DOI
zh-TW
Abstract
Predation is a primary cause of nest mortality in many nests of small passerines. And the difference of fauna causes different patterns of nest predation in temperate, tropical and subtropical region. Therefore bird would choose to select a safe nest-site to avoid predators. In order to determine the predation risks and to examine the effects of nest-site characteristics and nest microhabitat on nest success of small passerines with different nest types and with different nest predators, we monitored nesting success and identified predators of the shrub and the ground nests in a disturbed lowland forest in Huben Village, Yunlin County during two breeding seasons in 2006-2007. In total, we monitored eight species 205 nests included White-eyed Nun babbler (Alcippe Morrisonia) (n=103) and Fairy Pitta (Pitta nympha) (n=28), they were 135 shrub nests (85 predated nests, 1,331 observation days) and 70 ground nests (31 predated nests, 818 observation days). Nest daily predation rates were calculated using the Mayfield estima- tor. The nest daily predation rate of shrub nests (6.39±0.67%) was significantly higher than ground nests (3.79±0.67%, p <0.001). Nest predators were directly observed by use of digital video systems being used continuously to monitor active nests. We also based on documenting depredated nest condition and recording dental marks of predators to get the indirect evidence. Nest predators in the subtropical lowland forest included birds, mammals, snakes and ants. Snakes were the most important predators to both the ground nests (71.4%) and the shrub nests (69.3%). Among the snake predators, Taiwan tree snake (Boiga kraepelini), Taiwan kukri snake (Oligodon formosanus) and Pointed- scaled pitviper (Trimeresurus mucrosquamatus) were responsible for most predation events. While the shrub nests were more susceptible to birds and Formosan Macaque (Macaca cyclopsis), the ground nests were often predated by the ground-dwelling Crabeating mongoose (Herpestes urva) and Formosan gemfaced civet (Paguma larvata taivana). Finally, we used Mayfield logistic regression to analyze the relationship of predators and environmental factors, and also found that each type of predator searches for its prey in a different manner. The safety and success of nest sites of small passerines depended on the composition of nest predators in the area where they lived.
Subjects
亞熱帶氣候區
繁殖成功率
巢位特徵
鳥巢天敵
隱蔽度
天敵掠食風險
subtropical region
Taiwan disturbed lowland forest
nest survival rate
nest characteristics
nest predator
concealment
nest predation risk
SDGs
Type
other
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