Lasers Keep Crows Out Of The Corn

JAMES SCHLETT, EDITOR, james.schlett@photonics.com

From mid-July through October, just as New England sweet corn crops ripen, flocks of blackbirds, starlings, grackles and crows swarm and strip the fields, inflicting up to $800 in lost product per acre.

Traditionally, farmers have relied on propane cannons to scare the birds away with loud booms at random intervals. While an effective deterrent, the cannons are begrudged as much by people living next to cornfields as they are by the birds that ravage them. And that is why the Rhode Island Department of Environmental Management asked Rebecca Brown, a professor of plant sciences at the University of Rhode Island in Kingston, R.I., to study the effectiveness of a laser-based alternative at small farms.

Courtesy of the University of Rhode Island.

“We thought we should test this [technology] and get some data and share it,” said Brown.

Before researching laser bird control she had studied a process called “topping,” which involves cutting off corn stalks’ tops after they shed pollen, as a bird deterrent method. This labor-intensive technique removes crop topcover and makes birds in cornfields vulnerable to predators, but it was not embraced by farmers.

Meanwhile, laser bird control is gaining more traction in the agricultural industry. For example, the Bird Control Group in Delft, the Netherlands, along with Carpe Diem Technologies in Vancouver, British Columbia, Canada, offer agricultural laser bird-control solutions, which some Rhode Island farmers have already deployed. However, many commercial lasers cover areas far larger than the small New England farms involved in Brown’s study — the first of its kind in the region. For example, the Agrilaser Automatic, an automated system, has a range of 3,000 meters, allowing it to cover up to 3,000 acres, and the handheld Agrilaser Lite has a range of 1,000 meters. In contrast, Brown’s study involves an automated system with a commercial green laser pointer.

“You don’t need a high-power laser to cover an area of 10 to 15 acres, which is what our farmers are looking for,” said Brown.

An ear of sweet corn ravaged by birds. Courtesy of the University of Rhode Island.

Brown’s system horizontally sweeps the laser beam over the sweet corn. She noted that green lasers have been shown to be good at deterring flocking birds, whereas red lasers are ideal for roosting birds. After preliminary studies, she said the laser beam does not appear to injure the birds, which are sensitive to moving light and could perceive sudden flashes as a predator approaching from above.

An old folk tale recalls a Georgian farmer and his wife who slept in one Sunday. Noticing the inactivity on the farm, a flock of crows descended on its cornfields, prompting a rooster to cry, “Cock-a-doodle-doo — the crows are in the corn!” But the farmer and his wife slept through this alarm and awoke later to find their corn had been eaten. That is why in Georgia another way of saying, “It’s time to get up” is “The crows are in the corn.”

Maybe if lasers were around back then they’d be saying, “The right light in the morn keeps the fields full of corn.”