Metabolic rate and evaporative water loss in the silky starling (Sturnus sericeus)

To better understand the physiological characteristics of the silky starling (Sturnus sericeus), its body temperature (T_b), basal metabolic rate (BMR), evaporative water loss (EWL) and thermal conductance (C) elicited by different ambient temperatures (T_a) (5-30℃) were determined in the present study. Our results showed that they have a high T_b (41.6±0.1℃), a wide thermal neutral zone (TNZ) (20-27.5℃) and a relatively low BMR within the TNZ (3.37±0.17 mL O₂/g·h). The EWL was nearly stable below the TNZ (0.91±0.07 mg H₂O/g·h) but increased remarkably within and above the TNZ. The C was constant below the TNZ, with a minimum value of 0.14±0.01 mL O₂/g·h·℃. These findings indicate that the BMR, T_b and EWL of the silky starling were all affected by T_a, especially when T_a was below 20℃ and the EWL plays an important role in thermal regulation.