Stress and translocation: alterations in the stress physiology of translocated birds

Translocation and reintroduction have become major conservation actions in attempts to create self-sustaining wild populations of threatened species. However, avian translocations have a high failure rate and causes for failure are poorly understood. While ‘stress’ is often cited as an important factor in translocation failure, empirical evidence of physiological stress is lacking. Here we show that experimental translocation leads to changes in the physiological stress response in chukar partridge, Alectoris chukar. We found that capture alone significantly decreased the acute glucocorticoid (corticosterone, CORT) response, but adding exposure to captivity and transport further altered the stress response axis (the hypothalamic–pituitary–adrenal axis) as evident from a decreased sensitivity of the negative feedback system. Animals that were exposed to the entire translocation procedure, in addition to the reduced acute stress response and disrupted negative feedback, had significantly lower baseline CORT concentrations and significantly reduced body weight. These data indicate that translocation alters stress physiology and that chronic stress is potentially a major factor in translocation failure. Under current practices, the restoration of threatened species through translocation may unwittingly depend on the success of chronically stressed individuals. This conclusion emphasizes the need for understanding and alleviating translocation-induced chronic stress in order to use most effectively this important conservation tool

Gonadotropin-releasing hormone fibers contact POMC neurons in the hypothalamic arcuate nucleus

The metabolic state has long been shown to affect reproduction. Peripheral signals and hormones from the reproductive organs are also known to regulate energy metabol

The impact of live-trapping on the stress response of the meadow vole (Microtus pennsylvanicus).

In physiological research on natural populations, it is essential to understand the impact of capture-induced stress because of its numerous effects on many physiological processes. Our objective was to determine the extent to which the stress levels of meadow voles (Microtus pennsylvanicus) were affected by short-term responses to live-trapping and how these were influenced by the amount of time spent in live-traps. Baseline levels were obtained from a snap-trapped sample and stress levels were determined from voles that had spent variable amounts of time in live-traps (up to 16.5 h). Stress levels were inferred from corticosterone and glucose concentrations and hematocrit levels. In the live-trapped sample, corticosterone concentrations reflect only the stress of trap confinement whereas glucose concentrations and hematocrit reflect both the effects of trap confinement and handling. Live-trapping caused corticosterone concentrations to increase by 108% (from 390.3 ng/mL to 810.6 ng/mL), glucose concentrations to increase by 58% (from 55.4 mg/dL to 87.4 mg/dL), and hematocrit levels to increase by 10% (from 49% to 54%) from baseline levels. The length of time a vole spent in a live-trap did not affect corticosterone and glucose concentrations; however, hematocrit levels increased slightly over time (0.21%/h). We conclude that live-trapping induced a stress response in voles, but that longer times in traps did not increase the stress levels