LYNOTT, A.J.; BAKKEN, G.S.; BANTA, M.R.; Indiana State University; Indiana State University; University of Northern Colorado: Estimating the Body Temperature of Swimming Mallard Ducklings (Anas platyrhynchos) with Infrared Thermography

Body core temperature (T_b) is an important physiological parameter in thermoregulatory studies, but accurate measurements in young birds can be difficult. Radiotelemetry requires time to recover from surgery and associated inflammatory responses, and indwelling thermocouples impede movement and alter behavior. Inflammation and restraint often elevate T_b. As part of our study of thermoregulation in swimming 3-4d old mallard ducklings (Anas platyrhynchos), we explored the use of radiometric infrared thermography to estimate core T_b and changes in T_b. We compared the surface temperature of a shaved spot (< 1cm²)on the head measured with infrared thermography to cloacal T_b temperature measured by an indwelling thermocouple.. The shaved spot was located directly above the duckling’s brain, as we expected minimal thermal gradients in the thin layer of tissue between the brain and the scalp The thermal imager measured on average 3.01&deg C (&plusmn0.28&degC) lower than the thermocouple, but closely paralleled changes in the T_b of swimming ducklings. The average temperature drop of a swimming duckling for 60 minutes (n = 30) was -0.930&deg C (&plusmn0.37&deg C) when recorded by a thermocouple and -0.926&deg C (&plusmn0.37&deg C) when measured by the thermal imaging system. Neither water temperature (one-way ANOVA F_{3, 26} = 0.370, p = 0.605) nor air temperature (one-way ANOVA F_{3, 26} = 0.235, p = 0.676) had a significant effect on the temperature difference between the thermocouple and the thermal imager.