As color explodes and birdsong intensifies across central Missouri, the first pair of brown-headed cowbirds arrived on our property. Moving about the yard, the male engaged in his courtship display, anxious to mate with his bride; unfortunately, neither is willing to accept parental responsibilities.
Throughout the warmer months, the female will lay eggs in the nests of other songbirds; once they hatch, the young cowbirds, often larger and more aggressive than their nest mates, are raised by the adoptive parents, who may lose some of their own offspring in the process. By turning over parental duties to other birds, cowbirds augment their breeding efficiency and boost the population of their own species.
Birders thus tend to despise these homewreckers, empathizing with the exploited parents. But nature is neither fair nor sentimental and her web of life is festooned with unpleasant and seemingly cruel forms of animal behavior. In the case of cowbirds, their instinctual disruption of other families has proved to be a very effective survival technique.