Coping with novelty and stress in free-living house sparrows

Abstract

SUMMARYIndividuals respond differently to stressors and it has been suggested that stress responses are related to coping styles (consistent individual differences in behavior and physiology). We studied behavioral responses to a novel object and corticosterone response to stress during chick rearing in free-living female house sparrows (Passer domesticus). To prevent mates from influencing each others' behavior, we removed the males temporarily from nests and tested the females the following day either with a novel object placed on the nest box or as control. The two groups differed only in behaviors that were a priori defined as responses to the novel object (latency to first feeding, time spent near the nest, and inspecting the novel object by hovering in front of it) indicating that mate-removal per se had no effect on female behavior. Based on these variables, females' coping behaviors were categorized as 'bold', 'inquisitive' or 'shy' by discriminant analysis. Baseline corticosterone, measured on the day following the novel-object or control test, was not related to any measure of coping. Stress-induced corticosterone, however, was negatively related to number of hoverings in front of the nest (a measure of explorativeness) and accordingly differed between the behavioral coping categories, with 'inquisitive' birds having the lowest stress response. We propose that the relationship between physiological stress response and behavioral response to novelty (a component of personality or coping style) may be more complex than previously suggested, and individuals cannot always be unambiguously categorized along a single personality axis.

Boldness behavior and stress physiology in a novel urban environment suggest rapid correlated evolutionary adaptation

“…Generally, shyer or more passive behavioral phenotypes are predicted to be associated with more acute HPA axis activity and greater release of glucocorticoids in response to short-term stressors and vice versa for bolder or more assertive behavioral phenotypes (Koolhaas et al 1999). Results from artificial selection and observational studies support these predictions in birds and mammals (Korte et al 1997;Lendvai et al 2011) (but see Martins et al 2007). …”

Multiple indices of body condition reveal no negative effect of urbanization in adult house sparrows

“…Hematocrit was measured as the relative amount of red blood cells in total blood volume in the capillary tubes. For corticosterone measurement, blood plasma was extracted and kept at −20 • C until radioimmunoassay at the Centre d'Études Biologiques de Chizé following the protocol that was validated for house sparrows (Lendvai, Bókony, & Chastel, 2011). Briefly, total plasma corticosterone was measured in samples (25 l) after ethyl-ether extraction by radioimmunoassay using a commercial antiserum.…”

Evaluating the Stress Response as a Bioindicator of Sub-Lethal Effects of Crude Oil Exposure in Wild House Sparrows (Passer domesticus)

“…We conducted these studies in wild-caught house sparrows ( Passer domesticus ) brought into the laboratory. The house sparrow is a common model species for studying avian physiology generally [22] and the HPA axis specifically [21], [23], [24], and it is also easy to catch and keep in captivity. We had three goals in this study: 1) to elucidate what aspects of HPA function are compromised by oil ingestion, 2) to determine if any changes in HPA function could be detected by examining CORT concentrations in bird feathers, and 3) to compare effects on the HPA axis to several other potential biomarkers of oil exposure, including blood chemistry parameters and body weight, to evaluate whether the stress response is a useful bioindicator of sub-lethal chronic effects of crude oil exposure.…”