Prior to the publication of Birds of America, one way that Audubon earned income was by gathering bird specimens, dead and alive, and selling them to collectors and scientists. Of those that Audubon was able to capture alive while living and working in New Orleans was the Purple Grackle (present-day Common grackle). Audubon placed the grackles in a large cage with other types of birds that he had been able to catch and anticipated selling. But then the Common grackles started creating havoc rather than earning extra income for Audubon.
After a number of days of living in harmony, the Common grackles began harassing and even killing some of their unrelated cage mates. Audubon then removed the Common grackles and placed them in their own cage. “Even this did not prevent further breach of the peace, for the strong attacked and killed the weak of their own race, so that only a few remained in the end. The Grakles [sic] thus mangled, killed and partially devoured several Cardinal Grosbeaks, Doves, Pigeons, and Blue Jays. I look upon this remarkable instance of ferocity in the Grakle with the more amazement, as I never observed it killing any bird when in a state of freedom.”
Rather than restricted to fighting other species or one another in close confinement, a Common grackle in the wild is occupied by any number of other thoughts and concerns, such as cornstalks. Audubon shows in his drawing of the Common grackle in Birds of America: “How torn the husk is from the ear, and how nearly devoured the grains of corn already are!” This may not concern a farmer or a grower of corn crops if it was just a few husks that the Common grackle tears into. Instead, the Common grackle can gather in such large numbers in the fall that whole fields of corn might be devoured. On December 12, 2018, Drew Weber counted four million Common grackles along with two million Red-winged blackbirds in Lancaster County, Pennsylvania (see eBird Checklist S50950664).
Short of sticking up a scarecrow or pulling out a gun to shoot down Common grackles, farmers in North America have resorted to a wide variety of methods to defend their millions of acres of corn crops. Objects like bright-colored balloons having faces with eyes wide shut or long ribbons decorated with glitter and sparkles are secured high up on a metal pole. Gas-pressured cannons are fired to produce sonic blasts. Firecrackers are shot from 12-guage shotguns. Audio equipment is set up to play recordings of grackles that imitate the calls the birds make in distress. If farmers could only figure out how to cage the grackles, Audubon at least proved that they would soon take out each other.