The acute physiological response of polar bears to helicopter capture.

• Published in: The Journal of Wildlife Management
• Main Authors: Whiteman, John P, Harlow, Henry J, Durner, George M, Regehr, Eric V, Amstrup, Steven C, Pagano, Anthony M, Ben-David, Merav
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2022
• Subjects: blood biochemistry; body temperature; leukograms; polar bears; white blood cells; wildlife capture; Ursus maritimus
• Online Access: https://doi.org/10.1002/jwmg.22238; https://pubmed.ncbi.nlm.nih.gov/35915725; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9324155/

Many wildlife species are live captured, sampled, and released; for polar bears (Ursus maritimus) capture often requires chemical immobilization via helicopter darting. Polar bears reduce their activity for approximately 4 days after capture, likely reflecting stress recovery. To better understand this stress, we quantified polar bear activity (via collar-mounted accelerometers) and body temperature (via loggers in the body core [Tabd] and periphery [Tper]) during 2-6 months of natural behavior, and during helicopter recapture and immobilization. Recapture induced bouts of peak activity higher than those that occurred during natural behavior for 2 of 5 bears, greater peak Tper for 3 of 6 bears, and greater peak Tabd for 1 of 6 bears. High body temperature (>39.0°C) occurred in Tper for 3 of 6 individuals during recapture and 6 of 6 individuals during natural behavior, and in Tabd for 2 of 6 individuals during recapture and 3 of 6 individuals during natural behavior. Measurements of Tabd and Tper correlated with rectal temperatures measured after immobilization, supporting the use of rectal temperatures for monitoring bear response to capture. Using a larger dataset (n = 66 captures), modeling of blood biochemistry revealed that maximum ambient temperature during recapture was associated with a stress leukogram (7-26% decline in percent lymphocytes, 12-21% increase in percent neutrophils) and maximum duration of helicopter operations had a similar but smaller effect. We conclude that polar bear activity and body temperature during helicopter capture are similar to that which occurs during the most intense events of natural behavior; high body temperature, especially in warm capture conditions, is a key concern; additional study of stress leukograms in polar bears is needed; and additional data collection regarding capture operations would be useful.