by The total solar eclipse on April 8, 2024 coincides with an exciting time for wild birds. The local birds are singing to their friends and fighting for territories as they prepare for the once-a-year chance to breed.
Thousands of migratory birds will pass through the path of totality, and they migrate mostly at night.
Because birds use light to match their behavior to their environment, scientists like us have many questions about how they will respond to the eclipse. Will they pause their fighting and wooing and move toward sleep-like behavior? What about a nocturnal animal like an owl or those nocturnal migrants – will they start rustling from their roost before they realize it’s not night?
As behavioral biologists at Indiana University, we conduct research on wild breeding birds, with the goal of understanding why animals behave the way they do in response to environmental challenges and opportunities. For eclipse 2024, our team is launching a new project and developing an app. If everything goes as planned, we should end up with a large data set after the eclipse, collected by volunteer community scientists across the country.
There’s an app for that
On average, a total solar eclipse occurs in the same location only once every 375 years. Most wild animals, like most people, have never seen the sky change rapidly at night in the middle of the day. These rare events are a natural experiment that helps scientists like us understand how animals respond to an unusually sudden change in light.
Most of the research done on animal behavior during total solar eclipses is anecdotal. Observers have reported that animals at the zoo have acted restlessly or gone into their enclosures. Scientists have seen spiders starting to dismantle their webs at night in the middle of the day, and farmers have heard that their roosters start crowing one after the other, as if it were dawn again. Other reports suggest more subtle effects on animal behavior.
Massive amounts of standardized data can help make sense of these observations. But because the total covers such a large area of the universe in a short period of time, it would be impossible for one scientist or even a small team to get enough observations to find out why certain animals respond stronger for solar eclipses than others.
With collaborators across our campus – including Jo Anne Tracey in the Office of Science Outreach and Paul Macklin at Indiana University’s Luddy School of Informatics, Computing and Engineering – we’ve created an app called SolarBird.
Anyone can download SolarBird for free in the Apple Store and Google Play. The app asks participants to find a bird and watch or listen to it for 30 seconds, and click on some clues about what the bird does before, during and after the whole thing. You don’t need to have any prior bird knowledge or expertise to participate.
These types of public science projects have contributed to many scientific discoveries, and we hope the public will be able to help us learn more about bird behavior during an eclipse as well. Anyone can help. Even outlier observations collect important baseline data.
Technology and behavior of birds
Applications like Solarbird aren’t the only technologies that help researchers see beyond what any individual scientist can see or hear.
For example, during the August 2017 solar eclipse, researchers collected data from weather stations across the United States, including several locations along the path of totality. Like the weather forecaster on your local news channel, they used radar to detect movement in the skies, but instead of clouds, they focused on the radar signatures of insects and birds in flight.
The team saw some changes in activity – for the most part, the birds didn’t follow their normal daytime activity patterns as much, but they didn’t see any consistent increase in nighttime activity. Because they used radar, it is not clear exactly which bird behaviors increased or decreased.
The April 2024 eclipse will last longer than 2017, with four full minutes of darkness. And, with spring in high gear, birds are singing up a storm.
Bird songs typically convey two important messages: “keep away” to an opponent and “come here” to a potential mate. Singing is also easier for observers to notice. Most birds sing at 85 decibels, measured at 3 feet (1 meter) away. That’s the equivalent of a power mower – loud enough to notice that it’s happening or has suddenly stopped, even across your yard or public park.
Together with Dustin Reichard from Ohio Wesleyan University, our team has deployed passive audio recorders to record the effects of the eclipse on birdsong.
Researchers tracking wildlife have used autonomous recording units for years. These weapon-locked, weatherproof devices are about the size of a Kleenex box, and are usually attached to a tree and record almost anything within an earpiece. 20 of them are out now, at rural, suburban and urban sites.
Software advances are helping to automate the process of identifying bird songs by species with less work on the human side. We started recording the last week of March to collect song rates at dawn and dusk. We also measured important controls like how many birds usually sing at 3:06 PM, the peak of totality here in Bloomington, Indiana.
We hope to use these recordings to find out why certain animals may experience more or less solar eclipses.
For example, artificial light at night can affect the physiology, behavior and abundance of birds, and the total solar eclipse gives us a new way to test how light pollution affects behavior.
Urban birds may be used to strange changes in light. Forest dwellers may differ from grassland birds, based on the amount of light in their natural habitat. Alternatively, social species may amplify their warning calls, providing insight into how animals use social connections to navigate the unknown.
If you’re in the path of totality this April, be sure to join the celestial show. But you might want to look around and listen for birds, insects and other wildlife to see how they are reacting to this once-in-a-lifetime moment.
This article is republished from The Conversation, a non-profit, independent news organization that brings you reliable facts and analysis to help you make sense of our complex world. It was written by: Kimberly Rosvall, Indiana University and Liz Aguilar, Indiana University
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Kimberly Rosvall receives funding from the National Science Foundation.
Liz Aguilar receives funding from the National Science Foundation and the Indiana Space Grant Consortium.
