Canola field near Lind has a mysterious lark problem

J.R. Swinger didn’t quite believe his eyes when he checked on the newly planted spring canola on his farm near Lind, Washington. Not much rattles this sixth-generation Washington farmer, but he simply couldn’t figure out why only part of the canola had sprouted.

“You just begin to wonder what could have gone wrong,” Swinger said, standing in his replanted and now yellow-blooming canola field. “We just couldn’t figure it out until we noticed the birds.”

Swinger’s canola crop had become breakfast, lunch and dinner for hundreds, if not thousands, of horned larks. And it seems to be just farm fields in this part of Eastern Washington that are targeted by the winged marauders.

“They are kind of hard to count,” Swinger said, joking. “They just run over the field and peck, peck, peck.”

Horned larks are common ground-dwelling birds in open agricultural areas and are native to North America. The larks prefer prairie-type land or pasture, and though some migrate south in the winter, they are common year-round residents in Eastern Washington. They eat seeds during the fall and winter, but feed insects to their young.

Naturally, Swinger suspected the larks were feasting on the seeds, but upon closer inspection of empty seed shells and other leftovers, he discovered that the birds selectively ate the very tip of the sprout: the cotyledon, the first part of the plant that emerges from the seed.

Without the cotyledon, the plant can’t properly grow, and it dies. If the plant made it past the cotyledon stage, the birds left it alone.

“We are looking at a two- or three-day window. Once the plant starts photosynthesizing, the birds aren’t interested in it anymore,” Swinger said. “They must really like that tiny tip. I don’t know what else is driving them.”

At Washington State University’s Dryland Research Station in Lind, Bill Schillinger, a professor in the Department of Crop and Soil Sciences, recognized Swinger’s problem.

Horned larks had been destroying Schillinger’s canola research plots for the past 10 years, and he has tried a variety of things to deter the determined birds: He put up plastic owls, but the larks used them as perches.

“There was bird poop on them in the morning,” Schillinger said.

Then, he lined up propane-powered cannons, like the ones used to scare birds out of orchards, and set them off at random intervals, but the larks quickly adapted to those.

Schillinger even tried mixing “a large amount of garlic oil” in with the seed but that didn’t bother the larks either.

As a last resort, Schillinger tried covering the canola plot with netting that had 3/4-inch holes. He said it took four people four hours to secure the netting over a half-acre of canola. An irrigation pivot covers 125 acres – so not only was that obviously not a practical solution, it also didn’t work.

“Some of the birds got caught under the netting, and we thought that would distress the rest and keep them away,” Schillinger said. “It didn’t. It was like a feeding frenzy.”

Schillinger began contacting canola experts and growers all over the country, but no one had a similar problem. Even though he hadn’t found a solution to the lark problem, he decided to submit a scientific paper that was published in Industrial Crops and Products earlier this year.

“Most of the time, I submit scientific papers based on years and years of research,” Schillinger said. “I wrote this paper simply because it’s an interesting problem.”

Schillinger co-authored with Scott J. Werner, who’s a wildlife expert from the U.S. Department of Agriculture Wildlife Research Center in Fort Collins, Colorado.

Though Swinger was puzzled by the birds’ behavior, he wasn’t about to give up on his crop. After losing two irrigation circles to the larks this spring, he replanted and set out to find a deterrent.

“I just want to scare the birds away,” Swinger said, “but nothing worked. They just got used to it.”

Swinger called in falconer Raul Ramirez, who has trained his falcons to follow a small remote-controlled aircraft.

“The falcons scared them off right away,” Swinger said, “but they kept coming back.”

As long as the falcons were around, the larks returned less frequently and in smaller groups.

It was the addition of a friend with a rifle that finally did the trick.

“The falcons got the birds on the wings, and then if he fired right below the birds, they finally took off,” Swinger said. No birds were killed in this effort, he added.

Horned larks are protected under the federal Migratory Bird Treaty Act.

Swinger said as much as he enjoyed watching Ramirez work with the falcons, it’s probably not a financially sustainable solution. And it still doesn’t answer the question of why the birds prey on the canola seedlings.

“And how do they tell all the other larks?” Swinger said. “How do they know that it’s just the right time?”

Schillinger did an extensive literature search and said he can’t find the problem described anywhere else. He’s leaning toward it being a learned behavior, but ornithologists told him there’s no evidence of that.

“They don’t agree with me,” he said. “I guess we just don’t know why.”

Though most of the canola crop is grown in North Dakota, where Schillinger said the horned lark problem has not been described, it’s still important to find a viable solution for farmers like Swinger.

Schillinger said it’s expensive to replant canola, and if planting is delayed by one month – because the field has to be reseeded – the yield is reduced by 50 percent.

His plan is to try a nontoxic seed treatment this fall.

“It’s a compound that’s been used to deter other birds, so it may work,” Schillinger said.

Swinger isn’t about to stop growing canola, and he’s determined to find a way to keep the larks at bay. Like Schillinger, he believes the birds have learned to feed on the canola and that they bring their offspring back to the field.

“That would explain why it’s a localized problem,” Swinger said.

Another option would be to shield the young canola plants with a cover crop that could be sprayed away once the canola is mature enough and the larks aren’t interested in it.

“There’s many different things we can try,” Swinger said, “though we still don’t know how the birds know it’s just the right time.”

He said he’s proud of how hard he’s worked with Schillinger and other growers to find a way to deter the birds that doesn’t harm them.

“Perhaps I’m a little bit German and a little bit stubborn,” he said with a laugh. “But we will figure this one out.”