By Travis Weger

The European starling is an invasive species that destroys crops and causes a number of problems for military bases, utilities and farmers. Sierra Nevada employees learned exactly how pesky these birds could be when they took up residence at Maxwell Substation in Colusa County, California.

According to Time magazine, European starlings gather in flocks as large as 1 million birds and collectively consume up to 20 tons of potatoes in one day. Their droppings also carry several infectious diseases.

Partners in Flight, an organization dedicated to landbird conservation, estimates there are around 50 million European starlings in North America, making them a common pest with impacts that are difficult to mitigate.

Avian squatters
For more than 13 years, Maxwell Substation struggled with these impacts. As many as 10,000 European starlings were roosting overnight between October and April in the capacitor banks. When their droppings accumulated on or above the equipment, rain would wash the droppings into the insulators, increasing the potential for arcing and damage such as exploding capacitors and insulator degradation.

This compromised the stability and reliability of the substation. The excessive droppings even caused power outages, which were necessary for the cleaning of the fecal slicks from the equipment, and posed a health hazard to employees during cleanup and maintenance activities.

Close proximity to food, birdhouse-like equipment configurations and protection from predators are some perceived attractants of Maxwell capacitor banks for European starlings looking for a place to spend the night. In particular, though, the heat generated by the equipment made Maxwell Substation attractive to the birds, especially in the winter.

The equipment may have kept them warm, but it certainly wasn’t safe for starlings.

In 2012, about 400 of these birds were fried when their droppings caused a flashover that destroyed equipment and resulted in another unplanned outage. This was not a one-off problem, either; from that year forward, the starlings caused between one and eight outages for Maxwell Substation every winter.

A mixture of solutions
Biologists Tish Saare and Mike Prowatzke tried several different methods of repelling the starlings.

Their approaches included using a “squawk box,” which reproduces a sound birds use to warn each other of a dangerous area, and reflective bird deflectors.

These were not successful.

They also installed peaked slides, which were intended to deflect feces from the equipment but did not ultimately solve the problem. Neither did their attempt to purchase protective coverings for the diagonal insulators, as the team could not find a manufacturer that was able to make custom covers for the insulators that would not compromise system integrity.

“We’ve had some novel solutions proposed, including visual deterrent lasers and the deployment of falcons,” said Prowatzke. “But not falcons with lasers.”

Grape expectations
Finding a permanent solution ended up requiring some research.

“We contacted other utilities in the area for solutions on bird deterrents,” said Saare. “They recommended methyl anthranilate.”

Methyl anthranilate is a food-grade, FDA-approved chemical derivative that is safe for people, animals and equipment. In fact, it is used as grape flavoring in Kool-Aid, candy and soft drinks.

The grape-like scent is unpleasant to the European starlings and discourages them from returning.

The team used a handheld fogger resembling a leaf blower to mist the area with methyl anthranilate, but this did not prove to be a viable long-term solution.

One major issue with the handheld fogger was that somebody had to be present to operate it.

“The handheld machine is great when there is someone present in the yard,” explained Biologist Tim Langer, who the team contacted for assistance. “For long-term use, we needed a mounted device. One that could produce a lighter mist that isn’t blown away as easily by the wind. One programmable for dispersing throughout the day, each and every day, and especially when scout flocks are scoping out the capacitor banks.”

After a tip from Environmental Protection Specialist Andrea Severson, Langer discovered an automated mister that dispersed the methyl anthranilate much more effectively.

Flipping the birds
This system has so far proven to be a viable solution. The team installed three automated misters at Maxwell Substation between August and September 2017, programming them to run for extended periods.

The scout flocks, which scope out potential roosting areas before the rest of the European starlings follow, were expected to start arriving in October, but the fog successfully repelled them.

Keeping the scout flocks away – or, rather, encouraging them to scout elsewhere – has ultimately proven to mark the difference between success and failure. In fact, there were zero bird-related outages the following winter and the capacitor banks, insulators and other substation equipment no longer require power washing to remove bird feces.

The solution was not only a success, but it came in under budget. It also avoids lost revenue through potential outages, increases the safety of personnel and reinforces the reliability of the bulk electric system.

Rumors that it has increased a Kool-Aid craving for nearby employees have yet to be substantiated.​

Bird droppings on substation equipment

Droppings from European starlings coat substation equipment at Maxwell Substation in northern California. Too many droppings
could result in outages. Electricians and biologists use grape flavoring to discourage birds from roosting at the substation. 
(Photo provided by Sierra Nevada staff)

Last modified on September 12th, 2023