PS 1-5 - Full Metal Sparrow: Behavioral Adaptation to Environmental Lead (Pb) Contamination in a Commensal Passerine

Abstract: Lead (Pb) is a major anthropogenic pollutant known to cause a variety of deleterious health effects in exposed organisms. In the mining town of Broken Hill, NSW, Australia, a population of House Sparrows (Passer domesticus) that have been established in this heavily contaminated town for 120 years show signs of genetic adaptation to the leaded environment. While recent physiological assessments in the population have also demonstrated resilience by the sparrows to Pb poisoning, an assessment of likely shifts in behavioral responses was yet to be done. In summer 2022, over 600 sparrows were caught across Broken Hill’s well-characterized soil and blood Pb gradient, and a series of fitness-associated behavioral assays were conducted (takeoff flight, movement activity, aggression). Despite growing evidence on metal pollutants causing shifts in avian behavior, our assays yielded few connections between Pb levels and behavior among these sparrows. Concurrent work in a US-based, dosing experiment on captive sparrows has found that Pb exposure decreases House Sparrow behavioral performance in our assays, further contextualizing the remarkable resilience seen in the Broken Hill population.