Data from: Corticosterone: effects on feather quality and deposition into feathers

1. The concentration of the glucocorticoid hormone corticosterone (CORT)
is increasingly used in ecology and conservation biology as an integrated
measure of the historical record of an individual's
hypothalamo-pituitary-adrenal (HPA) activity during feather growth.
However, where and how CORT is incorporated in feathers is incompletely
known. 2. We therefore examined whether CORT is reliably measured with an
enzyme immunoassay, where CORT is incorporated in the feather and where it
affects feather quality, and whether CORT incorporation is related to
plasma CORT levels, feather growth rate and melanin pigmentation. 3.
During regrowth of plucked tail feathers, we injected pigeons with
tritium-labelled CORT, and implanted a CORT-releasing pellet to increase
plasma CORT concentration for about three days. In feather segments we
measured labelled CORT (DPM3H) and we quantified CORT with an enzyme
immunoassay EIA (CORTEIA) and double-checked the results with ultra-high
performance liquid chromatography-tandem mass spectrometry (LCMS)
(CORTMS). 4. Administered CORT affected feather structure and colour at
the very base of the feather (epidermal collar, ramogenic zone) and
reduced growth rate. In contrast, incorporation of CORT into the feather
happened mainly in the blood quill, as shown with all three methods
(DPM3H, CORTEIA, and CORTMS). 5. Incorporation of CORT into feathers was
only roughly proportional to plasma concentration, proportional to
feather-growth rate and increased with melanin pigmentation. 6. Measuring
CORT in feather is a way to reveal past events of increased stress during
feather growth in birds.