The Cliff Swallow Cities of Northwestern

Making a brief stop while feeding its young

The chittering cliff swallows made their grand return to the Lakeside this spring and settled in soundly throughout the month of May. At the top of the stark concrete columns of Northwestern University’s Segal Visitors Center, a colony of rust-colored heads and metallic blue backs flash in a whirr of nest-building commotion. In the beginning, only the smallest specks of mud dot the colonnade tops. Yet even just daubs of clay on these vertical faces are enough for the swallows to deftly balance on as they exchange excited, near-alien clicks and chirrs. No swallow sits still for long— a swooping dance to and from their perches is orchestrated to the echoes of a lone trumpeter practicing in the underground parking next door. Their graceful looping frequently overtakes the sailing beach skies in insect-grabbing frenzies that disperse just as quickly as they began. Lakegoers amble by, never noticing the protection provided to them by the valiant, white-masked mosquito vanquishers circling above.

Over the course of the month, the splashes of dried mud grow into the comfiest of curved, gourd-shaped nests that cling to the corners where the columns meet the limestone roof above. Meanwhile, the columns themselves grow streaked with white splatters from their new swallow residents. Cliff swallows excel at making all types of human-made escarpments into comfortable homes. Once found only in the rocky West, the development of large buildings, bridges, and other structures brought with it an expansion of cliff swallow territory. They have adapted and thrived, making their way further and further East one gulp of insects and social chitter of their beaks at a time.

But most birds cannot adapt to the consequences of humans’ award-winning feats of sustainable architectural design. The Segal Center and its concrete colonnades were erected on the Lakefront during 2012-2014, creating a scenic spot for Northwestern visitors and their vehicles, as well as destroying swathes of wild coastal vegetation that some of the millions of annually migrating birds relied on as they ventured through the Illinois flyway along Lake Michigan. The University paid the city of Evanston according to tree ordinance for the loss and this money was used to transform a slice of sand down the road into the Clark Street Beach Bird Sanctuary, bringing back the duney shrubs, trees and grasses that are so critical to bird habitats. Yet many more construction projects along the Lake have brought with them no habitat alternatives. For each beautiful Lakefront window view, there comes a sharp cost. The swooping of blue-sheened birds along the concrete walls of Northwestern’s cliff swallow cities tells a story of adaptation and resilience, but must not let us forget to heed warnings of the consequences of habitat loss.

The cliff swallow city