In the past, we have found that feathers and hair steroids are prospective biomarkers to predict the future survival of individuals in the wild. Glucocorticoid levels provide an indication of the state of the hypothalamic-pituitary-adrenal axis’ excitation level, including responses to stressors, energy storage and expenditure. Similarly, testosterone levels provide evidence of the hypothalamic-pituitary-gonadal axis activation, and the state of the reproductive and immune systems (among others). In addition to assessing the probability of survival, stress and sex steroids can be used to compare conditions in natural vs. disturbed populations and ecosystems. In multiple populations and systems, we quantify long-term integrated glucocorticoid and testosterone levels, and use them to model individuals’ survival, risk-taking behaviors (via giving-up densities), reproductive output, as well as ecological and behavioral data. The integration of these parameters can provide valuable insights that are vital for conservation and management decisions.