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On April 8, the moon will cross between the Earth and the sun, turning daylight into darkness across a —starting in Mexico, making its way from Texas up toward Maine, and finally popping out through Canada. 

Even for humans, who know what’s in store, the experience of a total solar eclipse is shocking: “The power of the eclipse is its strangeness,” says Doug Duncan, an astronomer at the University of Colorado who’s chased eclipses across the globe. “There are things that happen during a total eclipse that never happen any other time in your life.”

But birds and other animals have no idea what’s coming—and they can react in unusual ways when everything suddenly turns dark and cold. Over the decades, eclipse watchers have noticed some curious animal behavior during totality, the peak period when the moon moves fully in front of the sun, like Purple Martins pausing their foraging and nighthawks flying in the afternoon. On his own eclipse journeys, Duncan has witnessed everything from llamas gathering in Bolivia to whales and dolphins surfacing in the Galapagos.

Because eclipses are brief and uncommon, though, studies on these wildlife reactions can be tricky to coordinate. The window of totality for the April eclipse maxes out at around four and a half minutes, and after this year’s event, the contiguous U.S. won’t see another until 2044.

Still, researchers have been trying to make the most of these narrow windows, especially with the rare double-header of total solar eclipses crossing North America in recent years. In 2017, another total solar eclipse crossed the United States from coast to coast, giving scientists a chance to study how animals responded across the path of totality. And this year, more projects are set to add to this growing body of evidence.

Here’s what to know about the science behind wildlife and eclipses—and how you can be a part of it this April.

What the last eclipse revealed…

When a total eclipse crossed over New England in 1932, researchers put out a call for people to share their wildlife observations. In their —probably the first study to intentionally track animals during an eclipse—people reported owls hooting, pigeons returning to roost, and a general pattern of bird behavior that suggested “fear, bewilderment, or a belief that night was approaching.”

Nearly a century later, a slew of projects in 2017 also turned to community scientists to help understand these wildlife responses. With the eclipse crossing the country from the West Coast to the East, and millions of people in its path, “we essentially had the ability to collect a lot of data,” says Alison Young of the California Academy of Sciences.

More than 600 observers submitted their findings to iNaturalist that year as part of “,” a community science effort that Young helped organize. Many of their observations described an absence of wildlife during the eclipse’s peak, she notes: busy bird feeders clearing out, insects going quiet, flowers closing up. (Young proved her own dedication to the project by making sure to snap photos of a nearby ant colony during totality, even as her boyfriend was using the moment to propose to her.) Other community scientists that year also noted , , and .

Above: eBird observations of bird and insect activity during the 2017 eclipse. 

Some researchers decided to take more of a bird’s-eye view: A team from the Cornell Lab of Ornithology used radar data to see what flying animals got up to during the 2017 eclipse. They looked at observations from a weather radar station network run by the National Weather Service, which collects data about what’s happening in the air around the clock—including the clouds of insects and birds that zip around the skies. 

The researchers wanted to know: “How are the things that we’re normally tracking in the air going to react to this very special event?," says Cecilia Nilsson, a behavioral ecologist at Lund University. “At least for birds, it’s probably a once-in-a-lifetime experience.”

Their found that as the moon started to cover up the sun, there was a drop in biological activity in the air—suggesting that day-flying birds and insects were coming down to rest, says Andrew Farnsworth, a migration researcher at the Cornell Lab of Ornithology who worked on the study. But the fake dusk wasn’t enough to fool everyone: The radar didn’t show the spike in activity that usually happens after dark, when night fliers take off.

“The daytime activity is declining,” Farnsworth says. “But it’s not a powerful enough stimulus to create what happens typically at sunset, in terms of the emergence of lots of nocturnal insects, the exodus of birds migrating at night.”

…And what 2024 could teach us

This year is set to keep building out our knowledge. Many researchers have plans to repeat and refine their projects from 2017: Farnsworth and his team are excited to see what the radar has in store this time around, and Young is once again organizing an where people can submit their photos and observations.

The 2024 eclipse has some extra advantages for research, experts point out. The maximum length of totality is almost twice as long as in 2017, meaning there’s more time for animals to respond—and more time for humans to observe them, Young says. Plus, the April timeframe is closer to peak spring migration, which could mean birds are more motivated to take off when the sky gets dark, Farnsworth says.

This year, another major project will also aim to understand what animals are doing during the eclipse—by eavesdropping on them. The NASA-backed plans to gather audio recordings and observations from across the path of totality, after working on some smaller-scale efforts during the prior eclipse.

The team has already sent out hundreds of audio kits to volunteers across the country, and has for anyone who wants to build their own, says Henry “Trae” Winter, one of the project’s principal investigators. These community scientists will help place their recorders in locations in and around the path of totality, from backyards to wildlife refuges, and run them before, during, and after the eclipse—five days in total—to capture the shifting sounds of nature.

Once volunteers mail their memory cards back, the Soundscapes team plans to specifically look at the responses of crickets, which have been known to start their chirping when the darkness of the eclipse takes over. (Winter recalls a friend describing how in 2017, the start of totality sounded like “somebody turning on a cricket switch.”) But all of the eclipse recordings will also be shared publicly, so that other scientists can design their own studies using the massive amount of data collected, Winter says: “We can build this living database that will go on and be used by generations.”

With all of this research planned, scientists are hoping to get some concrete evidence behind centuries of anecdotes about wildlife and eclipses. “We have a pretty good idea of what might generally occur,” says Brent Pease, an ecologist at Southern Illinois University whose lab is partnering on the Eclipse Soundscapes project. “And here’s an opportunity for us to quantify that.”

Even though we don’t see eclipses very often, understanding these wildlife reactions could also help give us insight about broader questions in ecology, Farnsworth says—like how shifts in light and temperature act as cues for different behaviors in nature. “Really, the connection we’re thinking about here is how animals relate and respond to their environment,” he says.

How you can observe

If you don’t live along the path of totality and are able to travel, eclipse pros say it’s worth making the trek. “Even the slightest bit of sunlight that can get around the moon makes a huge amount of difference,” Winter says, which means being in the total eclipse path is a vastly different experience from even 99 percent coverage.

For Duncan, April will mark his 12th time seeing a total solar eclipse. Totality means the chance to see more interesting animal behavior, he says, along with “all of the wonderful stuff—the silver streamers of the sun’s corona stretching across the sky, and the pink flames, and people screaming and crying.”

Even in the partial zone, though, you can still pay attention to how nature responds—and contribute to science. Sending in your observations through a platform like iNaturalist or eBird can help provide valuable data for future research, and Young says reports from outside the path of totality can still reveal interesting insights about what level of sun coverage is needed for animals to react.

The Eclipse Soundscapes project is also looking for to record and share “field notes” of the changes they see, hear, and feel during the eclipse, whether they’re in the total path or not. By going beyond the visuals, the Soundscapes team hopes to make the big day more accessible for blind or low-vision people who are often left out of astronomy, Winter says, and to help everyone have a deeper experience of the rare event. “What we’re trying to do is have people be very mindful during the eclipse, and actually use all of their senses to determine what changes,” Winter says.

Pay attention to any animals around you, whether in a natural space or just a nearby bird feeder, researchers suggest. Take the time before and after the eclipse to notice any changes in how many animals are around, and how they’re acting. 

Of course, you should also save some time to just take in the big event. Even though we humans can understand when and why an eclipse is going to happen, it’s hard to be fully prepared for the true experience of totality—something that “sure looks like the end of the world,” Duncan says.

“When you’re standing there and something has just taken the sun away,” he says, “you can’t deny it.”