BBS data are analyzed annually by the USGS Eastern Ecological Science Center to estimate long-term trends in bird abundance across regions and species. These results help identify population declines, recoveries, and emerging conservation concerns. BBS data underpin hundreds of peer-reviewed publications.
Not all species produce reliable trends in Vermont. In some cases, birds occur too infrequently or are detected on too few routes to support robust analysis.
Below are just 3 of the over 150 species with data in Vermont. Interactive results can be explored through the national BBS data portal.
Estimated abundance over time for a Vermont BBS route. Green envelope represents 95% credible interval. Data from Hostetler et al. (2025).
