It is critical to understand how radiotransmitters and their attachment techniques impact marked individuals. Many studies of transmitter effects assess only overt, deleterious effects. However, physiological effects caused by attachment techniques might compromise the integrity of resulting information. Our objectives, therefore, were to assess the efficacy of subcutaneous implants and determine the physiological effects on mourning doves (Zenaida macroura) using heterophil: lymphocyte (H:L) ratios, and fecal glucocorticoid measures. We conducted 2 trials with 60 mourning doves; 1 in summer-autumn (trial #1) and 1 in autumn-winter (trial #2). For each trial we assigned 15 male and 15 female doves to either a subcutaneous implant treatment or a control group. During the 2 trials, we observed no differences in body masses, H:L ratios or fecal corticosterone levels between mourning doves with subcutaneous implants and the control group. Given the ultimate use of the information obtained from telemetry projects and cost of the resulting initiatives, expenditures associated with rigorous experimental evaluations can only improve the basis of reliable knowledge used in making resource management decisions