Large-scale context and local insight: songbird population trends in the Great Plains

Effective conservation of declining songbird species in the Great Plains of North America requires robust population trend estimates across spatial scales. We compared population trend estimates across spatial scales using data from the Breeding Bird Survey (BBS) and a targeted monitoring program for seven focal species associated with arid shrub-steppe and grassland habitats in central Montana, USA. Trend estimates from the two monitoring programs showed partial agreement, but consistency depended on how uncertainty and trend direction were interpreted, revealing both areas of concordance and key discrepancies. Thick-billed longspur ( Rhynchophanes mccownii ) was the only species to exhibit clearly divergent trends, potentially indicating localized population declines despite broader regional stability. Discrepancies likely reflect a combination of scale-dependent processes and differences in sampling design and inference, highlighting the importance of integrating multiple monitoring approaches. Our findings demonstrate that targeted monitoring can reveal local population declines and refugia, while large-scale monitoring like BBS provides essential regional context. Together, these two monitoring programs support more informed conservation and adaptive management in the Great Plains ecosystems.