Long-term history of vehicle collisions on the endangered Nēnē (Branta sandvicensis)

Vehicle collisions pose a growing threat to the endangered Hawaiian goose (Nēnē) in and around Hawai'i Volcanoes National Park, with mortality rates increasing over nearly four decades despite stable per-capita risk. A 40-year dataset revealed that while absolute Nēnē deaths rose from 1977 to 2014, the rate remained consistent. Mortality peaked during breeding season (November–December) and was concentrated along just three road segments, with no significant variation by location or sex. Surprisingly, mortality showed no correlation with visitor numbers or traffic volume, nor did it depend on population density. These findings highlight the need for targeted mitigation strategies, particularly in high-risk areas and during critical life stages.

Lepczyk, C. A., Fantle-Lepczyk, J. E., Misajon, K., Hu, D., & Duffy, D. C. (2019). Long-term history of vehicle collisions on the endangered Nēnē (Branta sandvicensis). Plos One, 14(2), e0210180. https://doi.org/10.1371/journal.pone.0210180