Chicago Breeding Bird Trends

by Morgan Harpster

A wealth of information is now available to those interested in Chicago breeding bird trends. The Bird Conservation Network (BCN), a local group of 21 conservation organizations, including the Chicago Ornithological Society, has released data from a 22-year study of the breeding habits of over 100 nesting species in a variety of natural habitats across northeastern Illinois.

BCN volunteers collected data from managed land in Cook, Lake, McHenry, DuPage, Kane, and Will counties through surveys conducted annually in June and July, counting breeding birds in designated habitats. Only birds that were sighted ten or more times during those months were counted in survey results. Over 200 volunteers assisted in these endeavors.

In positive news, many local bird species are "doing better than the rest of the state and elsewhere in the nation," per Eric Secker, President of BCN. This success is a result of “so much land that's being actively managed and restored” in the region. Sandhill Cranes, Pileated Woodpeckers, and Northern Mockingbirds have fared particularly well. Henslow's Sparrows stole the show, with an annual population growth averaging 3.4 percent. Other species showed steady growth, such as the Common Yellowthroat, the Ruby-throated Hummingbird, and the Warbling Vireo. However, some birds are declining in population including Ovenbirds and Bobolinks. Bobolinks prefer wetter areas than our area can provide, and it is theorized that clearing and burning is to blame for the decline in Ovenbirds. Other birds of concern as noted by the dataset are Black-billed Cuckoos, Cerulean Warblers, American Woodcocks, and Northern Bobwhites.

This study is not only of interest to birders and bird lovers, but may also serve as a call to action for researchers and land managers, who may be able to make changes that encourage a higher breeding bird population. A detailed accounting of the dataset can be found on the BCN website.

The Bird Conservation Network provides regular opportunities for citizen scientists to assist with data collection such as this, including monitoring year-round at specific sites, noting changes in nesting populations using point count surveys, and casual monitoring during a single visit to a site. To find out more, email bcnsurvey@gmail.com.