ILLINOIS—In late 2020, the Shawnee National Forest welcomed an unexpected winter guest—the red crossbill, a type of bird normally only found in the Pacific Northwest.

The birds were spotted by Mark Vukovich, a wildlife biologist on the Shawnee, on a routine visit to the Lee Mine area in Hardin County, Illinois. When Vukovich heard unfamiliar bird calls, he searched his bird app for sounds that matched. To his surprise, the call belonged to a red crossbill, a very rare winter irruptive migrant.

An irruptive migrant is a species that usually migrates short distances but occasionally moves far south in very large numbers. While the cause is not straightforward, these unique migrations are typically to seek food when there is a shortage of cone crops of conifers on preferred wintering grounds.

“I was stunned by how far this species has traveled to visit this part of the country,” Vukovich said. “The fact they’ve remained this long is also unusual for the Midwest.”

Vukovich is unaware of any other area in southern Illinois with a population of wintering red crossbills. His sightings suggest that selective timber harvesting on the Shawnee might be a factor drawing these birds. He first observed the red crossbills in units that were thinned in 2018 and 2019. On subsequent visits, he continued to see red crossbills concentrated in managed pine stands, actively feeding in the shortleaf pine canopy and seeking seeds in the cones. In fact, about a year removed from timber harvest, the area shows high numbers of many species of birds, not just these rare visitors.

Vukovich was even able to record a short video of the red crossbill.

Vukovich submitted a report to eBird, a bird citizen-science application that is monitored by local and regional ornithologists and birders. A Cornell University expert who examined the recorded red crossbill calls concluded they were Douglas fir and Sitka spruce red crossbills, meaning that the birds flew from the extreme western parts of the U.S. or Canada to Forest Service land in southern Illinois.

Even in an irruption year, it is unusual to see the red crossbill in southern Illinois. Douglas fir red crossbills normally stay in the Pacific Northwest, occasionally irrupting to other Western states and sometimes the Northeast when food gets scarce. The Sitka spruce red crossbill also inhabits the Pacific Northwest, from northern California to central Oregon, and usually travels to the same regions as the Douglas fir red crossbill during an irruption year.