The impact of human disturbance on behavior, heart rate, and plasma corticosterone of wild red-tailed hawks (Buteo jamaicensis) in captivity

Abstract

Behavioral assessments provide a non-invasive method for monitoring stress, while most traditional stress monitoring options require restraint and handling. The objective of the present study was to determine if behavioral assessments can be used to identify acute stress in wild red-tailed hawks (Buteo jamaicensis) during the wildlife rehabilitation process. Heart rate, plasma corticosterone, and behavior were assessed in red-tailed hawks at a rehabilitation facility when a human disturbance was present and when the disturbance was not present. Findings were compared between undisturbed and disturbed sessions. Behavior and heart rate data were collected remotely by using a remote human heart rate monitor and a video camera. Corticosterone was measured from plasma samples obtained immediately after the observation periods. During preliminary work, results from the human heart rate monitor were compared with a veterinary monitor to ensure accuracy, and no differences were found. Plasma corticosterone and heart rate increased significantly in the presence of a human disturbance, compared to undisturbed levels. Several behaviors were identified as “reactionary” due to an increase during disturbed sessions. Reactionary behaviors included: jumping to a new perch, lateral movement on perch, flight, tail shaking, leaning forwards, standing with wings extended, turning around, and crouching. A wild red-tailed hawk exhibiting these behaviors during wildlife rehabilitation may be displaying signs of an acute physiologic stress response.