Feather corticosterone in Northern Bald Ibis Geronticus eremita: a stable matrix over time able to predict reproductive success

Abstract

Measuring corticosterone concentrations in feathers (FCC) has been increasingly used as an integrated index of bird's response to stressors, offering valuable insights into subsequent carry-over effects. However, it is still unclear to what extent corticosterone levels deposited in feathers during the moulting period relate to individual physiology in high-energetic demanding situations. In addition, the stability and repeatability of FCC over the same feather generation and across successive generations are still unresolved questions. In this study, we assessed FCC in 24 captive Northern Bald Ibis, Geronticus eremita. We sampled body feathers on three occasions during two consecutive years (2015-2016) to explore within-individual stability of FCC in feathers grown during the same generation and test whether FCC was repeatable or varied between two consecutive generations. Then, we explored whether FCC (a) was associated with individual health status, (b) correlated with previous reproductive success and (c) was related to future reproductive success. Results showed high stability of FCC among feathers of the same generation, while FCC differed between successive generations. We also observed that FCC, age and health status were negatively associated with subsequent reproductive success the following season, while no association was found with previous reproductive success. Overall, our study supports the use of feathers as a stable measure of corticosterone over the same feather replacement generation and emphasizes the usefulness of FCC as a biomarker of subsequent reproductive success. Keywords Birds • Chronic stress • Glucocorticoids • Non-invasive • Biomarker Zusammenfassung Feder-Corticosteron beim Waldrapp Geronticus eremita: Eine zeitlich stabile Matrix ermöglicht Voraussagen über den Reproduktionserfolg Das Messen der Corticosteronkonzentrationen in Federn (engl. feather corticosterone concentration, FCC) ist ein immer stärker genutzter, integrierter Index für die Stressreaktion eines Vogels. Dies ermöglicht wertvolle Einblicke in nachfolgende Carry-Over-Effekte. Jedoch ist immer noch unklar, in welchem Ausmaß der Corticosteronspiegel, der während der Mauserzeit in den Federn erreicht wird, mit der individuellen Physiologie in energetisch höchst anspruchsvollen Situationen zusammenhängt. Weiterhin ist die Stabilität und Messwiederholbarkeit der FCC innerhalb einer und zwischen aufeinanderfolgenden Federgenerationen noch ungeklärt. In dieser Studie haben wir die FCC von 24 in Gefangenschaft gehaltenen Waldrappen Geronticus eremita untersucht. Wir sammelten Körperfedern zu drei verschiedenen Zeitpunkten in zwei aufeinanderfolgenden Jahren (2015-2016), um die individuenspezifische FCC-Stabilität in Federn der gleichen Generation zu untersuchen und um zu testen, ob die FCC-Messungen zwischen zwei aufeinanderfolgenden Jahren Communicated by L. Fusani.

Feather Corticosterone Measurements and Behavioral Observations in the Great White Pelican (Pelecanus onocrotalus) Living under Different Flight Restraint Conditions in German Zoos

“…The results of this study also reveal non-significant associations between CORTf, life parameters, and behavior. The finding that the pelicans’ sex did not affect CORTf is comparable to the findings of other studies such as those in northern bald ibises ( Geronticus eremita ) [ 32 ]. The age of the pelicans seems to affect CORTf.…”

Corticosterone in feathers of laying hens: an assay validation for evidence-based assessment of animal welfare

“…(2017) , it is recommended to use the same type of feather when analyzing and comparing feather corticosterone concentrations as the feathers have the same structure and time of growth. When drawing comparisons, feathers should origin from the same replacement generation as Monclús et al. (2020) found different levels of feather corticosterone in the same bird but from different seasons.…”

“…Subsequent studies on corticosterone in feathers were performed mostly in wild birds (e.g., Bortolotti et al., 2009 ; Koren et al., 2011 ; Lattin et al., 2011 ; Fairhurst et al., 2012 ; Lendvai et al., 2013 ; Harms et al., 2015 ; Kouwenberg et al., 2016 ; Aharon-Rotman et al., 2017 ; Freeman and Newman, 2018 ; Monclús et al., 2020 ), using feather corticosterone as a retrospective view on challenges the birds had to cope with during feather growth. Despite the wild birds, results of first investigations in poultry ( Berkvens, 2012 ; Carbajal et al., 2014 ; Jenni-Eiermann et al., 2015 ; Zeinstra et al., 2015 ; Johns et al., 2017 ; Weimer et al., 2018 ; Alba et al., 2019 ; von Eugen et al., 2019 ; Nordquist et al., 2020 ; Lindenwald and Rautenschlein, unpublished data) are also encouraging; however, in the absence of a standardized procedure, authors applied different methods to detect and quantify corticosterone in feathers.…”

Research Note: A sip of stress. Effects of corticosterone supplementation in drinking water on feather corticosterone concentrations in layer pullets

“…The measurement of feather corticosterone concentration ( fCORT ) is a comparatively new and increasingly used method in stress research in wild and captive birds as well as in poultry ( Carbajal et al, 2014 ; Romero and Fairhurst, 2016 ; Häffelin et al, 2020 ; Leishman et al, 2020 ; Monclús et al, 2020 ; Reese et al, 2020 ). Numerous studies have reported a stable incorporation of corticosterone in feathers and a positive correlation between corticosterone concentrations in feathers and in peripheral blood ( Bortolotti et al, 2008 ; Romero and Fairhurst, 2016 ).…”