On April 8, 2024, a total solar eclipse disrupted light-dark cycles for North American birds during the lead-up to spring reproduction. Compiling more than 10,000 community observations and artificial intelligence analyses of nearly 100,000 vocalizations, ornithologists at Indiana University found that bird behavior was substantially affected by these few minutes of unexpected afternoon darkness; more than half of wild bird species changed their biological rhythms, with many producing a dawn chorus in the aftermath of the eclipse.
Circles indicate distinct SolarBird app observations submitted on April 8, 2024. Image credit: Aguilar et al., doi: 10.1126/science.adx3025.
The daily and seasonal rhythms of birds are tightly governed by shifts between light and dark.
But what happens when those cycles are suddenly interrupted, such as during a total solar eclipse?
Although past studies have sought to understand the effects of solar eclipses on animal behavior, most have offered only scattered or anecdotal glimpses of how animals respond.
Indiana University researcher Liz Aguilar and colleagues saw the April 2024 total eclipse as a rare opportunity to investigate, providing an unprecedented natural experiment in how birds react to abrupt changes in light.
In anticipation of the eclipse, which cast nearly 4 minutes of daytime darkness across a large swath of the central and eastern United States, they created SolarBird, a smartphone app that allowed users to record bird behavior during the eclipse in real time.
Its use by citizen scientists generated nearly 10,000 observations spanning 5,000 km of the eclipse’s path.
At the same time, the researchers deployed autonomous recording units at sites across southern Indiana, which captured around 100,000 bird vocalizations before, during, and after totality.
These recordings were analyzed with BirdNET, an AI system capable of identifying species calls and quantifying vocal activity.
According to the findings, of 52 species detected, 29 showed significant changes in their vocal behavior at some point during the event, yet the eclipse did not affect all species equally.
In the minutes leading up to totality, 11 species sang more than usual as the sky darkened.
During the four minutes of darkness, 12 species responded, with some falling silent while others grew more active.
The strongest reactions came after the Sun returned, when 19 species changed their songs in what resembled a false dawn chorus.
Barred owls called four times more often than usual, while robins — who are well known for their pre-dawn songs — sang at six times their usual rate.
“These patterns suggest that the eclipse temporarily reset some birds’ biological clocks, prompting them to behave as though a new day had just begun,” the scientists said.
Their paper was published in the October 9, 2025 issue of the journal Science.
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Liz A. Aguilar et al. 2025. Total solar eclipse triggers dawn behavior in birds: Insights from acoustic recordings and community science. Science 390 (6769): 152-155; doi: 10.1126/science.adx3025