A glucocorticoid receptor antagonist affects corticosterone but not neophobia in wild‐caught house sparrows (Passer domesticus)

• DOI: 10.1111/jne.70009
• Publication Date: 2025-03-10T06:22:34Z
• Authors: Marquise S. Henry; Melanie G. Kimball; Ella B. Cochran; Blake A. Dusang; William J. Frazier; Keegan R. Stansberry; Tosha R. Kelly; Emily G. Stelling; Christine R. Lattin
• Keywords: Corticosterone; Neophobia; Passer

Abstract Avoidance of novel stimuli (neophobia) affects how wild animals interact with their environment and may partly determine whether persist in human‐altered landscapes. The neuroendocrine mediators neophobia are poorly understood, although past work demonstrated that experimentally reducing circulating corticosterone wild‐caught house sparrows ( Passer domesticus ) decreased toward objects placed near the food dish. In this experiment, we directly tested role one two types receptors, glucocorticoid receptor (GR), mediating by administering a GR antagonist (RU486, n = 10) or vehicle control (peanut oil, over 5 consecutive days measuring responses to both pre‐ post‐treatment. We also measured baseline stress‐induced all on final day behavior trials. To better understand effects RU486 time, separate group 12) administered took multiple blood samples assess corticosterone. Overall, did not detect an effect subcutaneous injections behavior. However, find significantly levels starting 1 post‐injection 6 post‐injection, compared vehicle‐injected controls. Our results suggest is involved sparrows.