Bat activity jumped 50% at solar farms in the Midwest, as farmers cultivated nearby fields, and researchers think vegetation beneath panels may be to blame.
Spring changes the sound of the countryside. Fields that have spent the winter covered in crop residue are opened up, machines are driven through the soil and many plants disappear in a matter of days. For bats that hunt after sunset, this seasonal shift can change where it is easier to find food.This became evident in a two-year monitoring project at 12 commercial solar installations in the American Midwest, published in the journal Global Environment and Conservation by Soldatitis and colleagues in 2025 and titled “Bat activity in environmental solar developments in the Midwestern United States‘. Ultrasonic detectors recorded bat activity around the facilities and in nearby agricultural fields during the warmer months of 2023 and 2024. The difference was particularly evident in May and June, when planting was underway. Above the solar arrays, the night air carried much more bat activity than it did on the surrounding farmland. The reason seems to have less to do with the panels themselves than with what grows underneath them.
How solar farms gave bats greener hunting grounds
The project’s solar sites weren’t just swaths of panels surrounded by barren land. They are designed as eco-developments, with native prairie plants planted under and between the infrastructure.Around adjacent crop fields, spring preparation may leave large areas of exposed soil. Tillage removes much of the plants that emerged after winter, while subsequent agricultural treatments can alter insect conditions further. For insect-eating bats moving across the landscape at dusk, the difference between a recently worked field and an area still bearing flowers and grasses can be significant.Solar sites offered a somewhat different environment. Native grasses and wildflowers remained in place beneath the panels, providing vegetation and habitat for insects at a time when the surrounding agricultural landscape was undergoing a major transformation.
Bat activity increased by 50% over solar farms in May and June
The equipment used in the project did not record the normal sounds that people hear from the ground. The detectors are designed to pick up the high-frequency echolocation calls produced by bats as they move and hunt.Across 12 solar projects, these recordings revealed that bat activity was generally greater in solar installations than in coupled crop fields. During May and June, the difference averaged about 50 percent when comparing weekly activity between the two types of sites. This was not a uniform difference throughout the year. This became particularly evident during the early part of the growing season, when the surrounding farmland was prepared and planted.After sunset, when bats come out to forage, the airspace above solar installations is used more heavily than nearby agricultural fields.
Three species of bats didn’t behave exactly the same way
The recordings also showed that the response was not identical between the detected species. Hoary bats tended to make more calls over solar installations during most of the observation period. Big brown bats showed a more concentrated seasonal response, with activity within solar sites being high during approximately the first part of the season before becoming less pronounced later.The silver-haired bat was different again. Their recorded activity was broadly similar between solar developments and agricultural comparison sites.These differences are worth keeping in mind. A changing landscape does not necessarily trigger one universal response from all bat species moving across it. Their diets, movements, and preferred hunting conditions can vary, as can the way they use plants and open air space.
What grows under the panels may be the important part
It would be easy to look at the result and attribute it to solar panels. However, the recordings cannot prove that the panels themselves were attracting bats. Plants beneath the structures offer another explanation.Native prairie plants can provide flowers, shelter and habitat for insects. During early spring, when nearby fields are stripped of much of their vegetation for planting, those planted areas can still be relatively productive. Plant-associated insects can provide bats with a useful source of prey.Solar infrastructure effectively creates a different patch within the agricultural landscape. The panels occupy the upper part of the site, while underneath are plants that are managed to achieve environmental value rather than simply treating them as empty space around an energy facility.For bats traveling through densely farmed landscapes, a patch of native vegetation can become a useful stopping point or hunting area, especially during a period when suitable insect habitat is less abundant elsewhere.
What the bat calls it can reveal and what it cannot
Acoustic detectors are very good at showing the presence and activity of bats. They can detect changes in the frequency and timing of calls, helping researchers understand how animals use different parts of the landscape. But hearing more echolocation calls doesn’t automatically mean bats are catching more insects.Animals may be traveling through the area, exploring, hunting in vain, or using the airspace for many different reasons. To determine whether solar sites actually provide better feeding opportunities, researchers will need to look more closely at the calls associated with capturing prey and examine insect communities at the same time.The next layer of evidence could help separate simple presence from true foraging benefit. It will also show whether the effect is stronger during the early planting period or persists after surrounding crops are established.
Solar farms can create habitat as well as energy
These findings add to a growing body of work investigating what happens when renewable energy projects are placed within working landscapes.Solar development does not have to be an ecological wasteland. When native plants are established and maintained, the space beneath the panels can function differently than the surrounding farmland. In this case, the contrast was particularly evident during a short period of the year when crop fields were disturbed and native plantings remained intact.The distinction is important because solar installations occupy land for decades in many cases. So decisions about what to plant under the panels can affect more than just the appearance of the site.For bats, the Midwest study suggests a fairly simple possibility: The most beneficial feature of an eco-solar farm may not be the panels above, but the living landscape underneath.Microphones could hear the difference before anyone could pinpoint exactly why this was happening. More work on insects and feeding behavior would help fill this missing piece.
