What did birds and insects do during the 2017 solar eclipse?

Radar study finds less activity during the event

Date:  November 15, 2018

Source:  Cornell University

In August of 2017, millions peered through protective eyewear at the solar eclipse -- the first total eclipse visible in the continental United States in nearly 40 years. During the event, researchers from the Cornell Lab of Ornithology and the University of Oxford watched radar to observe the behavior of birds and insects. Their findings have just been published in Biology Letters.

Using data from 143 weather radar sites in the continental U.S. -- 8 of which covered areas of eclipse totality -- researchers were able to "see" the behavior of wildlife during the eclipse, which produced conditions similar to sunset.

"It's not so easy to observe what wildlife are doing during an eclipse. It's dark," quips Cecilia Nilsson, lead author and Edward W. Rose Postdoctoral fellow at the Cornell Lab. "But using radar data we could actually monitor behavior on a very large scale. Overall, we saw a decrease in normal daytime activity."

Nilsson and her team looked at wildlife behavior in the air on radar two days before and after the eclipse and compared this activity with the behavior observed during the eclipse. They found that although typical daytime activity in the air decreased -- behavior such as foraging for food -- typical nighttime activity did not increase -- behavior such as high-flying migration.

This result was surprising. Instead of triggering night-time behavior, the sunset-like sky produced by the eclipse stifled activity. But Nilsson noted that insect and bird behavior during the increasing darkness could have been due to a general sense of confusion.

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