Prospects and pitfalls of using feathers as a temporal archive of stress events and environmental pollutants: a review and case study

Abstract

Methods to assess environmental pollution and stress responses in birds with scarcely invasive or non-invasive sampling are highly sought after in ecology and conservation. For several years now, feathers have been promoted as non-invasive tools to assess stress physiology and environmental pollution in birds. This has mainly been applied in whole feathers, but more recently also in feather segments. In this study we explored the prospects and pitfalls of feather segment analysis as a means to obtain data retrospectively over an extended time period and with a high temporal resolution. We first provide a literature review focusing on corticosterone and heavy metals measured in feather segments. Second we present a case study in which we simultaneously assessed corticosterone and lead in segments of Golden Eagle (Aquila chrysaetos) feathers. By combining a review and case study, we identify four key prospects of feather segment analysis and their respective pitfalls. We conclude that multi-substance feather segment analysis has a high potential, but there is a strong need for its further validation.