Are Birds an Economic Pest on Northwest Dairies? New Research Aims to Find Out


That birds can be a pest for fruit growers is no surprise. But what about to cows?

Are birds a pest on dairies? Do they bother the milk cows? And do they cause economic losses?

Researchers in Washington state are trying to find out.

A substantial portion of Washington’s 471 dairies are located in the northwest corner of the state, and that area has also seen substantial new acres planted in blueberries and raspberries, explained Washington State University dairy management specialist Amber Adams-Progar.

“As more and more berries came into the area, we started seeing more and more night roosts in barns on dairies,” she said. “And the question is, ‘Is this a problem, and if so, how can we fix it?’”

Birds – primarily European starlings – flock to the dairies during the winter months, roosting in barns, eating feed put out for the milking herds and contaminating that feed with their feces. In the spring, they largely leave the dairies and go back to being a problem for berry growers in the northwest corner of the state and grape growers in the Yakima Valley.

Adams-Progar and her team of researchers crafted a survey for the state’s dairy farmers, asking about bird damage.

“There was a small survey a few years ago that just scratched the surface,” she said. “And of the dairy farmers that responded, there was a wide range in their estimates of the economic loss caused by birds, from $1,000 a year to $200,000 a year.”

The new survey was designed in collaboration with U.S. Department of Agriculture research economist Stephanie Shwiff and is much more detailed and focused.

“We have to get a better grasp on this,” Adams-Progar explained. “A $1,000 a year loss isn’t a significant problem for most operations, but $200,000 a year is huge. We need a better understanding of the true costs and true economic impact.”


The Research

The team has been conducting bird counts on 11 dairies, and just finished installing video cameras on four to monitor the behavior of the cows as they interact with the birds.

“I’ve been at farms where there were so many birds on the feed in the feed bunks that cows had to push them out of the way with their noses to eat,” Adams-Progar said.

Does that bother the cows? And if so, does it bother them enough to have an economic effect?

As an animal behavior specialist, Adams-Progar wants to know.

The team is also looking at more directly measurable impacts. They’re analyzing the nutritional content of new feed – what the cows should be getting – and comparing that to the nutritional value of the feed that remains after birds have picked it over. And they’re looking at the type, quantity and effect of the pathogens introduced into feed through bird fecal matter.

If the results show there is a problem and quantifiable loss, the next step will be looking for solutions using an integrated pest management approach.

“Our goal is to test different bird-deterrence methods with a focus on ones that could be more environmentally friendly and sustainable,” Adams-Progar said. “Can we use netting in barns to limit their entrance? Can we draw in more raptors or other natural predators and does that make a difference?”

The research team also includes Dr. Susan Kerr, a Washington State University regional dairy and livestock specialist and Karen Steensma, associate professor of biology and environmental studies at Trinity Western University, who is a dairy farmer herself. But it may expand in interesting ways.

An idea they’re discussing with colleagues in computer sciences and engineering is an autonomous bird-scaring drone. It’d be designed to look like a bird of prey that would come out periodically, fly through the barns to chase off the starlings, then return to its charging perch.

“It’d be like a Roomba for birds,” Adams-Progar said.