Long term stability of corticosterone in feathers

Area of Science:

• Endocrinology
• Avian Biology
• Ecological Physiology

Background:

• Non-invasive physiological assessments are crucial in wildlife research.
• Feather corticosterone analysis offers long-term, retrospective insights.
• Steroid stability within feather matrices over extended periods requires further validation.

Purpose of the Study:

• To determine the long-term stability of corticosterone in stored European starling feathers.
• To assess the reliability of feather samples for retrospective physiological measurements over 14 years.
• To compare corticosterone quantification methods (RIA vs. EIA) in aged feather samples.

Main Methods:

• A homogenous pool of European starling feathers was created in 2009.
• Subsamples were repeatedly assayed for corticosterone using radioimmunoassay (RIA) over 14 years.
• Results were compared between RIA and enzyme immunoassays (EIA) to evaluate method-specific differences.

Main Results:

• No significant effect of storage time (14 years) on measured feather corticosterone concentrations was detected via RIA.
• High variability was observed across time points, but low variability within individual assays.
• Enzyme immunoassays (EIA) yielded higher corticosterone concentrations compared to RIA, likely due to antibody binding affinities.

Conclusions:

• Stored feather samples are reliable for long-term retrospective corticosterone quantification.
• The findings support the use of museum specimens for historical physiological studies.
• Corticosteroid measurements in other keratinized tissues may also be stable over time.