Evaluating the Effect of Short-Term Capture and Handling on Fecal Glucocorticoid Metabolite Levels in Mourning Doves

The measurement of stress hormones (i.e., glucocorticoids) has greatly advanced animal conservation. Fecal glucocorticoid metabolite assays are valuable because they are noninvasive, but their ability to detect responses to short-term (<30 min) stressors in a way similar to blood serum assays is comparatively less well understood. We evaluated whether fecal glucocorticoid metabolites (FGMs) increased in captive wild mourning doves (Zenaida macroura) exposed to either a brief (<2 min) capture, handling and release (CHR) or capture stress protocol (CSP; i.e., capture, hold for 30 min, release) treatment. Previous studies have shown that mourning doves exhibit elevated FGMs within 2-3 hrs of experimental challenges. Therefore, we attempted to collect feces every hour for 24 h pre-treatment and 36 h post-treatment. We did not detect a consistent increase in FGMs in response to CHR or CSP treatments. Though additional research is needed, FGM levels were lower the longer birds were held in captivity and we did not observe sex-based or seasonal differences in FGM responses. For mourning doves, and likely other species, plasma corticosterone analysis is better suited to assess responses to short-term stressors. Alternatively, FGMs are ideal for research focused on longer-term patterns in physiological state because they are not sensitive to exposure to temporary, acute stressors.