Seasonal variation on metabolism and thermoregulation in Chinese bulbul

1Seasonal changes in a bird's physiology and behavior are considered to be a part of an adaptive strategy for survival and reproductive success. To understand modes of metabolic adaptations, the metabolic rate (Vo2), body temperature (Tb), and thermal conductance (C) of the Chinese bulbul (Pycnonotus sinensis) in the Zhejiang Province of China were determined in the summer and the winter at a temperature range from 5 to 35 °C, respectively.2The thermal neutral zone (TNZ) of the Chinese bulbul was between 26 and 33 °C in the summer and between 25 and 32.5 °C in the winter. With a temperature range from 5 to 35 °C, the mean Tb was 40.3±0.1 °C and 40.2±0.1 °C, in the summer and in the winter, respectively. Minimum C was 0.24±0.01 ml O2 g−1 h−1 °C−1 in the summer and 0.25±0.01 ml O2 g−1 h−1 °C−1 in the winter.3The mean basal metabolic rate within TNZ was 2.86±0.16 ml O2 g−1 h−1 in the summer and 3.36±0.12 ml O2 g−1 h−1 in the winter.4Chinese bulbuls showed seasonal metabolic acclimatization similar to other temperate wintering passerines. This improved cold tolerance was associated with a significant increase in Vo2 (18%) in the winter relative to the summer.