On April 8, 2024, a total solar eclipse interrupted the daylight cycles of North American birds as they prepared for spring breeding. Researchers at Indiana University, after analyzing over 10,000 community observations and utilizing artificial intelligence to examine nearly 100,000 bird calls, discovered that bird behavior was significantly impacted by the few minutes of unexpected afternoon darkness. More than half of the bird species altered their biological rhythms, leading many to produce dawn choruses in the aftermath of the eclipse.
Circles indicate individual observations from the SolarBird app submitted on April 8, 2024. Image courtesy of Aguilar et al., doi: 10.1126/science.adx3025.
The daily and seasonal rhythms of birds are closely regulated by variations in light and darkness.
What occurs when these cycles are abruptly disrupted, such as during a total solar eclipse?
Previous research has explored the effects of solar eclipses on animal behavior, yet many studies have only provided scattered or anecdotal insights regarding animal responses.
Indiana University researcher Liz Aguilar and her team viewed the total solar eclipse in April 2024 as a unique research opportunity, offering an unprecedented natural experiment to observe how birds react to sudden light changes.
In preparation for the solar eclipse that would cast nearly four minutes of darkness over large regions of the central and eastern United States, they developed a smartphone app called SolarBird, which allows users to document bird behaviors in real time during the eclipse.
The citizen scientists’ contributions resulted in almost 10,000 observations spanning 5,000 km along the eclipse’s path.
Simultaneously, researchers deployed autonomous recording devices across southern Indiana to capture the calls of about 100,000 birds before, during, and after the totality.
These recordings were analyzed using BirdNet, an AI system capable of identifying species calls and measuring vocal activity.
Findings revealed that 29 out of 52 species detected exhibited significant changes in their singing behavior at various points during the event, although the eclipse’s effects varied among species.
In the moments leading up to the eclipse, 11 species were found to sing more than usual as darkness approached.
During the four minutes of darkness, 12 species reacted—some becoming silent, while others increased their vocal activity.
The most notable responses were observed after the sun re-emerged, with 19 species adjusting their songs to mimic a false dawn chorus.
Notably, barred owls hooted four times more frequently than usual, while robins—renowned for their pre-dawn melodies—hooted six times more than normal.
“These patterns indicate that the solar eclipse temporarily reset the internal clocks of certain birds, causing them to act as if a new day had commenced,” the researchers stated.
Their paper was published in the October 9, 2025 edition of the journal Science.
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Liz A. Aguilar et al. 2025. Total solar eclipses trigger dawn behavior in birds: Insights from acoustic recordings and crowd science. Science 390 (6769): 152-155; doi: 10.1126/science.adx3025
Source: www.sci.news
