Data from: Poleward range shifts of breeding birds in Wisconsin

Climate change is causing shifts in the geographic ranges of multiple
species across the world. Birds are a critical taxon for observing range
shifts because their high mobility allows them to track shifting climates
over time and space. Breeding bird atlases are large-scale breeding bird
surveys that are essential for tracking species’ ranges in response to
climate change. In this paper, our goal was to analyze Wisconsin’s
Breeding Bird Atlases (1995­–2000 & 2015–2019) to document changes
in range size, mean latitude, and range boundary shift of breeding birds.
Concordant with our predictions, we found that many southerly bird species
with northern range limits were both expanding in distribution and
shifting their range boundaries poleward. Contrary to our predictions,
northerly species with southern range limits in the state were not
shifting their boundary poleward but demonstrated a northward movement in
their mean latitudes. Despite the lack of range boundary shift for
northerly species as a group, 86% of climate-vulnerable boreal species
demonstrated a shift northward in their overall distribution. The repeated
signal of bird ranges moving poleward remains a coherent fingerprint of
the impact of modern climate change on species and ecosystems.