The Breeding and Foraging Ecology of the Taiwan Laughing Thrushes, Garrulax morrisonianus, in the Tatachia Area, Taiwan

• Main Authors: Shu-chun Yu, 游淑鈞
• Other Authors: Hsiao-Wei Yuan
• Format: Others
• Language: zh-TW
• Published: 1999
• Online Access: http://ndltd.ncl.edu.tw/handle/32438392303286476218

碩士 === 國立臺灣大學 === 森林學研究所 === 87 === I studied the breeding and foraging ecology of Taiwan Laughing Thrushes (Garrulax morrisonianus) at Tatachia, in the mountains of central Taiwan, from April 1997 to December 1998. I examined parental care, nest site selection, and intersexual and interseasonal foraging resource partitioning. Taiwan Laughing Thrushes are monogamous. Their breeding season began in March and ended in August. Both parents shared the duties of nest building, incubation, brooding and feeding. The clutch size was always 2, and the eggs averaged 31.3 +1.5 mm in length. Parental feeding frequency increased with the nestling age, and invertebrates were the most common food type. Within breeding territories, nesting sites were located in areas with the highest tree densities. Males and females foraged at different heights. Males foraged on branches above 8 m more than females and on branches below 8 m less than females. During the breeding season, Taiwan Laughing Thrushes foraged at lower (0-2 m) and higher (8-14 m) heights, on shorter (0-2 m) and taller (6-14 m) plants, on smaller (0-5 cm dbh) and larger (15-40 cm dbh) trees, on smaller (0-1 cm dbh) branches, and exhibited more glean, flake, pry, sally, and sally-strike behaviors, and ate more invertebrates, flower petals, and larger food items (1-6 cm) than during the nonbreeding season. The foraging behavior of Taiwan Laughing Thrushes was influenced by food availability, plant phenology, weather, and seasonal changes in their endogenous physiological requirements. Taiwan Laughing Thrushes seem to be opportunistic birds. Seasonal variation in foraging behavior probably results from changes in food availability.