Strolling through a century: replicating historical bird surveys to explore 100 years of change in an urban bird community

In 1898, Herbert and Alice Walter started a 5-year survey of birds in
Lincoln Park, – the largest park in Chicago, IL – and summarized their
data in an urban birding field guide, ‘Wild Birds in City Parks’.
Twenty-nine years later, William Dreuth compared the relative frequency of
species between the Walter’s study to their own 5-year Lincoln Park
survey. Between 2012 and 2015, we replicated these surveys to investigate
a century of bird diversity and community composition change in urban
Chicago. While species richness did not change, community composition did.
We found that 1) species with a greater diet breadth and 2) species that
increased in statewide occupancy were more likely to increase in frequency
over time. We conclude that factors at multiple scales brought temporal
changes to Chicago’s bird community. Overall, this survey highlights the
slow and subtle ways in which species may respond to a century of urban
intensification.