Adreno-immunological response to healthcare facility noise during rehabilitation of Tropical Screech Owls

Abstract

Wild animals, particularly those affected by urban expansion frequently face challenges such as vehicle collisions, and encounters with domestic dogs. Rehabilitation in care facilities usually conducted in ex-situ conditions poses considerable challenges. In rescue centers, these animals are exposed to a new environment characterized by human noise and the presence of multiple species in a confined space. This can potentially trigger stress responses and immunosuppression, further compromising their health. This study aimed to assess the endocrine and immunological parameters of owls (Megascops choliba) under human care for a continuous 49-day period. Twelve adult owls were exposed to audio recordings from a rescue center between days 15 and 35. Fecal samples were collected from each owl every seven days, as well as blood samples from eight of these birds. Fecal samples were analyzed for glucocorticoid metabolites (GCM), while blood samples were used to measure plasma corticosterone levels, bacterial killing ability (BKA), and heterophil-to-lymphocyte ratio (H/L). Our findings revealed that GCM concentration increased during noise exposure regardless of sex, while plasma corticosterone levels remained unchanged. BKA decreased during noise exposure compared to before treatment, but H/L did not differ between time points. These results show that exposure to rescue center noise induces alterations in allostatic mediators in owls, requiring further research to address other physiological changes in individuals that may affect their recovery and maintenance under human care.