This program is a follow-up to our February 2021 30 Billion Birds Lost program by Ken Rosenberg of Cornell. This program will discuss a new expansive study of North American bird population trends that was published in Science May 2025.

Effective bird conservation has been limited by a lack of fine-scale population data. This talk presents new analyses using data from eBird to estimate changes in abundance for 495 North American bird species from 2007 to 2021 at a 27-kilometer resolution. Results reveal widespread but spatially complex declines; while 75% of species are declining overall, 97% show both increasing and decreasing trends in different areas. Strikingly, declines are often steepest where species are most abundant. These findings offer a new lens on population dynamics and provide sharper tools to guide urgent, targeted conservation efforts.

Bio: Dr. Courtney Davis is an Assistant Professor of Global Biodiversity and Ecoinformatics at Cornell University. Her research integrates large-scale data science, ecology, and conservation biology to understand the status and trends of biodiversity. She leads interdisciplinary projects that harness participatory science data, remote sensing, AI, and statistical modeling to inform conservation decision making and practice. Her work has been featured in leading scientific journals and widely used by agencies, NGOs, and the private sector working to conserve global biodiversity.