Feather corticosterone levels are not correlated with health or plumage coloration in juvenile house finches

Stressful developmental conditions can have both short- and long-term effects on animal physiology and behaviour, but studies on this topic are rarely conducted in the wild and, if so, largely focus on only the first few weeks of life. To fill this gap, we tested developmental links between early-life stress and the physiology of wild-caught juveniles later during development. Specifically, we examined potential associations between feather corticosterone levels of hatchling house finches (Haemorhous mexicanus) and several phenotypic and physiological traits measured several months later in juveniles. We assessed four indices of health (oxidative damage to lipids, innate immunity, intestinal parasite infection intensity and plumage colour) and two morphological traits (body mass and tarsus length) in juveniles. Feather corticosterone content was not related to any of the juvenile traits later in development. Our results suggest that physiological variables can change rapidly during ontogeny, such that stress hormone levels in juvenile feathers could be uncoupled from the real stress levels experienced by nestlings. Instead, juvenile physiology might be more dependent on current environmental conditions than on early-life conditions (i.e. environmental matching), and this may limit the effects on fitness of poor early-developmental conditions.