As I watched a male Brown-headed Cowbird take an extended bath in our basin, a male Northern Cardinal flew in hot. “Bath time’s up for you!” his squawks and body language made clear. His behavior was more aggressive than usual. Given the season, I wondered if he might be protecting a nearby nest. A pair (or more) of cardinals has been flying regularly from woods across the street to our birdbath and feeder.
The cowbird population near our home has grown noticeably. Rare individual sightings have become routine visits by small flocks. I looked up the species and discovered it is a native bird. However, it is also parasitic. Brown-headed Cowbirds don’t build their own nests. Instead, they sneak their eggs into other bird’s nests, where unsuspecting parents end up raising the hatchlings, which can soon outgrow them.
Cowbirds often remove the original eggs—unwelcome behavior with so many bird species facing habitat and population loss. With no nests to build or young to tend, a cowbird can produce three dozen eggs in a summer, taking her pick of suitors, as well as nests built by more than 220 species. Cowbirds have been observed using “mafia-style” intimidation to compel hosts to raise their young and destroying nests if hosts don’t comply.
This successful but irresponsible breeding strategy seems connected to the cowbird’s historically nomadic lifestyle. They followed herds of bison that churned up insects in the open grasslands these birds prefer, leaving their eggs in other bird’s nests along the way.
Brown-headed Cowbirds appear to be adapting and spreading to areas where forests are being converted to suburban grasslands. There are thousands of new homes under construction within a few miles of our home—a possible explanation for why we’re seeing more cowbirds (and other birds). Many people consider them a nuisance and take steps to discourage cowbirds from their feeders.
Angry Birds
Back at the birdbath, Mr. Cowbird dropped his head, turned his body sideways to the interloper. He moved slowly, as if leaving the water of his own accord. Mr. Cardinal took over the tub and began a long bath of his own.
After some minutes, a black bird swooped in, wings spread and squawking. Mr. Cardinal was so startled, he converted his bathing flutters into full flight in one motion and disappeared.
Only when I processed the photo did I realize the arriving bird was a female cowbird. Was she retaliating for the male? Or do these birds just not get along? Could be both, but definitely seems like Cowbirds vs. Cardinals is a thing.
I try not to judge wildlife by human standards, but it’s hard not to take sides when such rogue birds challenge a favorite species known for its beauty, singing and cooperative parenting.
