Effects of radiotransmitters on body mass, feed consumption, and energy expenditure of northern bobwhites

Radiotelemetry is commonly used in northern bobwhite (Colinus virginianus) research. An underlying assumption is that radiomarked individuals provide unbiased estimates of population parameters. Our objectives were to evaluate the effects of radiotransmitters on body mass and feed consumption of radiomarked and banded-only pen-raised bobwhites in a controlled environment and to compare daily energy expenditure (kJ/g/day) between treatments in a simulated field setting. We randomly assigned a treatment (i.e., radiomarked or banded-only) to 40 pen-raised bobwhites and placed them in individual cages (51- × 27- × 28-cm) within an environmental chamber. We conducted 2 separate 21-day experiments to simulate summer (35°C daytime high, 23.9°C nighttime low, 15-hour photoperiod) and winter conditions (18.3°C daytime high, 4.4°C nighttime low, 10-hour photoperiod) typical for south Texas. For the field experiment, we evaluated energy expenditure via doubly labeled water for radiomarked (n=5) and banded-only pen-raised bobwhites (n=5) in a flight pen (50- × 30- × 4-m). We documented no difference in change in body mass or feed consumption between radiomarked and banded-only bobwhites during either experiment (P>0.05). We also found no difference in daily energy expenditure between radiomarked (0.839 ± 0.056 kJ/g/day) and banded-only pen-raised bobwhites (0.804 ± 0.014 kJ/g/day; P=0.77).