Effect of isolation and conspecific presence in a novel environment on corticosterone concentrations in a social avian species, the zebra finch (Taeniopygia guttata)

• Published in: Hormones and behavior Vol. 60; no. 3; pp. 233 - 238
• Main Authors: Banerjee, Sunayana B., Adkins-Regan, Elizabeth
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01-08-2011; Elsevier; Elsevier BV
• Subjects: Animals; Behavioral psychophysiology; Biological and medical sciences; Birds; Corticosterone; Corticosterone - blood; Environment; Finches - blood; Fundamental and applied biological sciences. Psychology; Handling (Psychology); Hormones; Hormones and behavior; Isolation; Male; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Restraint; Social buffering; Social Isolation; Stress; Stress, Psychological - blood; Taeniopygia guttata; Zebra finch; Zebra finch; Isolation; Restraint; Social buffering; Corticosterone; Stress; Steroid hormone; Zebra; Glucocorticoid; Vertebrata; Mammalia; Environment novelty; Taeniopygia guttata; Adrenal hormone; Perissodactyla; Aves; Ungulata
• ISSN: 0018-506X; 1095-6867
• DOI: 10.1016/j.yhbeh.2011.05.011

Zebra finches are a highly social and monogamous avian species. In the present study, we sought to determine the effect of social isolation (separation from the flock) in a novel environment with and without a conspecific present on the adrenocortical activity of paired and unpaired individuals of this species. With regard to paired birds, we hypothesized that the presence of the mate during isolation from the group would act as a social buffer against the stressful effects of isolation. We observed that 10 but not 30minutes of social isolation resulted in elevated concentrations of corticosterone in unpaired and paired male zebra finches in comparison to baseline concentrations of corticosterone. Furthermore, the presence of a mate during isolation in a novel environment did not have a buffering effect against increases in corticosterone concentrations. Additionally, to compare concentrations of corticosterone in response to isolation (in a novel environment) to a previously well-established stressor, we subjected groups of birds to restraint. We observed that 10 or 30minutes of restraint led to significantly higher concentrations of corticosterone as compared to baseline. Finally, to rule out the possibility that merely handling a bird would result in significantly elevated concentrations of corticosterone as compared to baseline samples, we measured corticosterone concentrations 10 or 30minutes after handling involving capture and release only. Our results suggest that handling alone might have contributed to the elevation of corticosterone in birds exposed to 10minutes but not 30minutes of restraint. Handling by itself did not account, however, for the elevated corticosterone in birds socially isolated for 10minutes.
► As little as 10minutes of social isolation in a novel environment causes activation of the hypothalamic–pituitary–adrenal axis of zebra finches, indicated by elevated corticosterone. ► The presence of the pair partner or other familiar conspecific does not prevent this response; social buffering by one other individual does not occur. ► After 30minutes of social isolation in a novel environment, corticosterone is no longer elevated; the acute hormonal response to isolation is short-lived.