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Corticosterone levels of tufted puffins vary with breeding stage, body condition index, and reproductive performance

TitleCorticosterone levels of tufted puffins vary with breeding stage, body condition index, and reproductive performance
Publication TypeJournal Article
Year of Publication2008
AuthorsWilliams, CT, Kitaysky, AS, Kettle, AB, Buck, LC
JournalGeneral and Comparative Endocrinology
Volume158
Pagination29–35
Abstract

Corticosterone(CORT) levelsin free-living animalsare seasonallymodulatedand vary with environmentalconditions.Although most studiesmeasuretotal CORT concentrations,levelsof corticosteroidbindingglobulin(CBG) may also be modulated,thus alteringthe concentrationof CORT availablefor diffusioninto tissues(free CORT). We investigatedthe seasonaldynamicsof CBG, total CORT, and free CORT inbreedingtufted puffins(Fraterculacirrhata)during2 years characterizedby high rates of nestlinggrowthand survival.We then comparedconcentrationsof total CORT in this populationto levelsin chick-rearingpuffinsat another colonyduring2 years with low productivity.At the high productivitycolony,levelsofCBG, total baselineCORT, free baselineCORT, and total maximumCORT were all higher prior to egg-layingthan duringlate incubationand late chick-rearing.Levelsof CBG were positivelycorrelatedwith body conditionindex (BCI) and free baselineCORT was negativelycorrelatedwith BCI. Total baselinelevelsof CORTduringchick-rearingwere two to four times higher at the colonywith low rates of nestlinggrowth andsurvival.Our results demonstratethe need for long-term datasetsto disentangleseasonaltrends in CORTlevelsfrom trends driven by changes in environmentalconditions.Given the negativeeffects associatedwith chronic elevationof CORT, our results indicatethe cost of reproductionmay be higher duringyearscharacterizedby low productivity.

DOI10.1016/j.ygcen.2008.04.018
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