Resurveying breeding forest bird communities in Western Oregon after 50 years: comparing 1968–1970 and 2020–2021

Accurate assessments of changes in breeding bird populations require regular, structured surveys or, alternatively, carefully documented benchmarks that can be precisely repeated. We resurveyed a historic benchmark of forest bird communities in Western Oregon, USA, originally conducted by Stanley Anderson between 1968-1970. Anderson’s thesis uniquely preserves detailed plot locations, species density estimates, vegetation structure summaries, and methodological descriptions—an uncommon level of documentation for the time. To facilitate accurate comparisons and future resurveys, we explain how we aligned our methods with Anderson’s and incorporated modern bird counting techniques. We also provide our raw data, metadata, and methodological details to ensure transparency and reproducibility.