A long-tailed bird flies past us, into a thicket of brush. The interns and I stand for minutes, peering into the brush. We see a flash here, a tussle there. Someone spots a red eye. It's a black-billed cuckoo, an admittedly secretive bird. Standing only feet from the tangle of willow and aspen where the bird landed, we still couldn't make out where it was located.
The unique call of the cuckoo—“coo-coo-coo”—often greets early mornings or fills late summer nights during the breeding season. The black-billed cuckoo is one of the fastest birds to rear its young, taking on average 17 days from egg laying to fledgling.
Like most wild animals, the cuckoo's diet dictates its habits and ecology. Cuckoos especially enjoy caterpillars, and large infestations of caterpillars can attract higher populations of cuckoos. Additionally, high caterpillar density during the breeding season can cause these birds to deliver a second clutch of eggs. The problem with caterpillars, for cuckoos, is that the spines and defense mechanisms of the caterpillar can get caught in their digestive system. Cuckoos periodically shed their stomach lining to combat this issue.
Relatively common in Wisconsin, cuckoos prefer upland wooded or shrubby areas. You can find black-billed cuckoos, or at least hear them, at our Faville Grove Sanctuary along North Shore Road.
Photo by Jeff Bryant, Flickr Creative Commons