North Carolina Mini Breeding Bird Survey: 27+ years of avian population data on a changing landscape, 1999–2025

Abstract

Long-term standardized surveys are the cornerstone of our ability to measure changes in populations. Throughout North America, the North American Breeding Bird Survey (BBS) has been instrumental in documenting population changes on a broad scale. However, individual survey routes are often far apart, posing a challenge to assessing population dynamics at a fine spatial scale or to address responses to local land-use change. Community science efforts like eBird have helped to fill this gap by expanding spatial coverage, but the lack of standardized survey effort limits its suitability for evaluating trends. To bridge this gap, we present the North Carolina Mini Breeding Bird Survey (NCMBBS), a long-term, standardized breeding bird surveying program designed to provide high spatial resolution data for three counties in central North Carolina. The NCMBBS has been conducted annually since 1999 and has so far surveyed 208,366 individuals of 119 bird species as of 2025. The temporal extent of the NCMBBS enables analysis of long-term population change, while the spatial coverage supports study of local drivers of change. The NCMBBS complements large-scale programs such as the BBS by enabling multi-scale analyses of standardized data. The data are available for reuse under the MIT License, and users should cite this data paper if they make use of the NCMBBS and acknowledge the contributions of the volunteers who conduct our surveys.