by Bird damage to crops results in millions of dollars of financial loss each year. To address this issue, researchers from the University of Florida and the University of Rhode Island in the United States have been investigating the effectiveness of laser scarecrows as a high-tech solution using light to deter birds.
In a recent study published in Pest Management Science, the researchers presented captive flocks of European Starlings with fresh ears of sweetcorn and demonstrated that devices emitting a moving laser beam can significantly reduce damage to the crop up to 20 meters from the laser device.
Kathryn Sieving, Professor of Wildlife Ecology and Conservation at the University of Florida and corresponding author of the research, explained that more and more growers are seeking inexpensive and portable laser units, like the ones tested in the research.
“The growers need big effects for affordable prices, and if they can spend $300–$500 each for lasers to protect large fields for 1-3 weeks instead of more expensive options such as hiring people to patrol with dogs, falcons, or rifles, then lasers would be beneficial,” she said.
One reason lasers provide an effective solution for protecting sweetcorn is the short vulnerability window before harvest, during which birds would target the crop. This short window reduces the risk of birds becoming desensitized to the lasers.
Sieving explained, “Lasers are being explored widely for crops with short vulnerability windows, like sweetcorn. They seem to be performing very well, especially when different non-lethal deterrents are combined, such as lasers with loud noises. Birds only attack sweetcorn during the brief ripening phase (called the milking stage) and it lasts only 5-10 days. So, as soon as it ripens, harvest begins.”
Therefore, the protection for sweetcorn does not need to last very long, and lasers seem to be working well by surprising birds and reducing damage during the milking stages by more than 20%.
The study consisted of two types of trials: Stick Trials and Natural Trials. In Stick Trials, fresh sweetcorn ears were mounted on sticks at varying distances from laser units, while in Natural Trials, birds foraged on ripe corn grown from seed in a flight pen. Laser and control treatments were alternated daily over five days to assess the birds’ response to repeated laser exposure.
Sieving explained the purpose of the Stick Trials, saying, “We designed the stick trials to increase the sample size for more robust results. Natural corn matures over several weeks, but then is only attractive to birds for two weeks, so our planted crop was not going to give us enough sample size. With the stick corn experiments, we could study small-scale effects and increase the sample sizes.”
The results showed that lasers reduced sweetcorn damage slightly in Stick Trials and significantly in Natural Trials. Sieving explained the difference in effectiveness, stating, “The sticks we presented corn on were sturdy, and the birds likely could perch and feed on corn while avoiding the laser layer sometimes. Natural corn stalks are flimsy, though, and the birds would be bouncing in and out of the laser layer with no control. Thus, just as in larger fields, it seems that natural corn makes lasers quite effective.”
The researchers also examined how the distance from the lasers affected the amount of damage to the sweetcorn. They found that there was effective deterrence up to 20 meters from the laser source. However, beyond this distance, damage to the crop increased, with little to no deterrence at 30 meters. Sieving noted that this data is unique and was possible to obtain because the experiments were conducted with captive birds.
However, Sieving explained that in true field settings, this effect seems to be unimportant. “In open fields, birds will simply leave a field with detectable laser protection, and they fly far out of its influence. It seems that just one laser per field can often do the trick to keep birds mostly out of a field. So, the fine-scale spatial effects might only apply if birds were overly committed to feeding a small area — then a grower may need to add a couple of laser units with overlapping ranges.”
Sieving hopes that laser scarecrows can offer a sustainable solution for the protection of crops with short vulnerability windows. Unlike acoustic deterrents that produce loud noises several times per hour, lasers are silent. Lethal deterrents require permits and time and labor to apply, and their potential toxic effects on wildlife, soil, and water are often unacceptable.
By using laser scarecrows, growers can reduce bird damage to their crops while minimizing disturbances to neighboring communities and minimizing negative environmental impacts.
*Note:
1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it
