Author: Jessica Leigh Hester / Source: Atlas Obscura
When the moon got in the sun’s way last August, people were expecting it. Many of us humans snapped up hotel rooms years in advance and traveled great distances to stand together for a few minutes in darkness.
Millions more North Americans just gazed up wherever they happened to be, equipped with flimsy solar glasses (for gawking at the celestial wonder) and phones (for documenting their own awe).We knew it was coming, but other animals didn’t. They didn’t mark their calendars, or book beds or flights, or road-trip to Oregon. For almost all of them, complete darkness in the middle of the day was a foreign concept. Prior to August 2017, the contiguous United States hadn’t witnessed a total solar eclipse since 1979. “None of the birds had experienced anything like this,” says Cecilia Nilsson, a postdoctoral fellow at the Cornell Lab of Ornithology. “It hadn’t happened within their lifetime.”
As Atlas Obscura reported just before the eclipse, many scientists planned to study what happened in the moments of darkness, and in particular how animals reacted to them. It’s not the first time researchers have done this: Reports from the 1850s and 1930s documented responses such as ants skidding to a stop and crickets chirping “as loud as on any summer’s night.” But in many respects, 2017 marked a new frontier of eclipse-animal data-gathering. This time around, scientists in the United States had cheap, reliable technology and an untold number of eyeballs paying attention.
By some estimates, nine in 10 adults in the United States got a (hopefully protected) eyeful.More than a year later, scientists are still sifting through their heaps of data. Here are three ways they tuned into how the celestial marvel affected animal behavior, and how they’re going to continue to dig into their data.
Weather radar
For a true bird’s-eye view, a team led by Nilsson collected data from 143 Doppler stations across the country.
These seemed to be ideal sources data about how animals reacted to the changing light, because those data were already being collected. These radar networks scan the sky every five or 10 minutes, Nilsson says. Meteorologists consult the images for information about clouds and rain, and usually filter out anything else. Nilsson and her team were interested in precisely that other stuff that would normally be tossed out as background noise. These data gave them a way to analyze “the entire assembly of birds in the air,” Nilsson says.
The radar data isn’t granular enough to tell a crow from an owl, but the researchers say they can consistently differentiate groups of birds or insects from rainclouds by analyzing the shape, movement, and altitude of things that appear on the scans.
The researchers wondered whether they’d find that birds had behaved during the eclipse the way they do at night. As Nilsson and her collaborators write in a new paper in Biology Letters, the data didn’t really bear that out. Instead, the researchers found that daytime routines, such as foraging for food, decreased, but weren’t replaced by nighttime habits. For the most part, everything simply quieted down.
There was an exception, however, in the zone of totality, the roughly 70-mile-wide swath of shadow that the eclipse cut across the heart of the country. At the eight stations there, the team detected a flurry of activity. Researchers observed a series of “blooms,” which look a bit like a jagged donut. These spikes seem to represent “really short bursts” of action among a large number of flying creatures, Nilsson says, generally lasting the length of a single scan cycle. They peaked during totality and were gone five or 10 minutes later.
It’s hard to say exactly what was taking to the air, or in what quantities. To distinguish between birds and insects on radar, Nilsson often looks at the speed at which the radar hit is moving—but in this case, the movements were “short and undirected,” so that was difficult to gauge. She suspects that the blooms may represent some form of discombobulation. “My guess…
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