Evaluating The Effect Of Short Term Capture And Handling On Fecal Glucocorticoid Metabolite Levels In Mourning Doves

D S Jachowski,B E Washburn,T W Mong,J H Schulz,J J Millspaugh

doi:10.2461/wbp.2014.10.5

Abstract

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.

Highlights

Measurement of stress hormone production in wildlife has dramatically improved our understanding of their physiology, behavior, and conservation [1, 2, 3, 4]
Baseline fecal glucocorticoid metabolites (FGMs) values for individuals in both treatment and control groups were in a similar range of 25-32 ng/g, and we observed no discernible trend in FGMs following our summer 2001 CHR treatment (Fig. 1)
Our study was restricted to a small number of individual birds, failure to observe consistent elevations in FGMs following CHR or capture stress protocol (CSP) treatments suggests that, compared to blood, fecal sampling is not sensitive to elevations in glucocorticoid concentrations in response to short-term, acute stressors in mourning doves

Summary

Introduction

Measurement of stress hormone production in wildlife has dramatically improved our understanding of their physiology, behavior, and conservation [1, 2, 3, 4]. Monitoring changes in fecal glucocorticoid metabolite (FGM) levels provides a noninvasive alternative to monitoring glucocorticoid concentration in blood plasma [16, 17, 18, 19]. FGM analyses have been widely used, in wild settings, because samples can be collected frequently and non-invasively from focal individuals [20, 21] and FGMs might provide a broader integrated measure of the stress response than blood glucocorticoid levels [22]. When FGM techniques are combined with behavioral studies involving capture, handling, and restraint to collect biological data (e.g., attach leg bands or radio transmitters), it is important to determine whether or not fecal glucocorticoid analyses are capable of detecting associated short-term stress responses if and when they occur [25, 26]

Methods

Results

Conclusion