Analysis of feather corticosterone

Corticosterone is a hormone involved in the regulation of metabolism and the prevalent glucocorticoid hormone in birds. While corticosterone has habitually been measured in blood plasma, this project examines corticosterone in the feathers of Alpine Swifts and Golden Eagles.

Aims

Following a validation study that showed that the analysis of feather corticosterone is a suitable method to measure stress retrospectively and throughout the moulting period (Jenni-Eiermann et al. 2015), this method shall now be applied in ecological studies.   

Approach

Alpine Swift: In collaboration with Pierre Bize from the University of Aberdeen, we measured corticosterone in the body feathers of nestlings. Corticosterone concentrations can be analysed in relation to various individual characteristics as well as climatic factors, the purpose being to examine correlations between stress during the nestling period and the return rate as well as the impact of weather and food conditions on the stress axis. In addition, the study also investigates whether the response of the stress axis is passed on to offspring.

Lead ammunition and Golden Eagles: In her Master’s thesis, Kathrin Ganz measured both lead and corticosterone in the feathers of Golden Eagles and was able to show that feather segment analysis is a suitable method to obtain data retrospectively over an extended time period and with a high temporal resolution (Ganz 2016, Ganz et al. 2018). Measuring several substances in the same feather segments allows us to determine environmental pollutants and stress responses in birds by means of non-invasive sampling.

Significance

Until now, corticosterone has typically been measured in blood plasma. The plasma concentration of corticosterone reflects the present release of corticosterone and allows us to make inferences about an individual’s current physiological state. We have demonstrated that corticosterone can also be reliably detected in feathers. It is incorporated during moult and provides information on the bird’s state at that time. In addition, the analysis of feather corticosterone allows us to study carry-over effects into the next stage of the life cycle.

Publications