Short Stuff: Brown-Headed Cowbird

The brown-headed cowbird is a North American brood parasite that avoids the labor of nest-building and parenting by laying its eggs in the nests of other bird species. Originally known as "bison birds," these creatures evolved a nomadic lifestyle following bison herds across the Great Plains, necessitating the abandonment of their offspring to keep pace with the moving animals. Despite the near-extinction of bison and the cowbirds' transition to following sedentary cattle, they retain this parasitic behavior, often outcompeting host hatchlings through rapid growth and aggressive food-seeking. While some hosts like the yellow warbler attempt to bury cowbird eggs under new nest layers, many birds are successfully fooled. Remarkably, cowbird hatchlings avoid imprinting on their foster parents, instead utilizing specific auditory cues and mysterious nighttime excursions to identify and join their own species upon reaching maturity.