On April 8, 2024, a total solar eclipse disrupted the light-dark cycles of North American birds during the period before spring breeding. By compiling more than 10,000 community observations and artificial intelligence analyzes of nearly 100,000 vocalizations, Indiana University ornithologists found that bird behavior was significantly affected by those few minutes of unexpected afternoon darkness; more than half of wild bird species have altered their biological rhythms, with many producing a dawn chorus the day after the eclipse.
Circles indicate separate SolarBird app observations submitted on April 8, 2024. Image credit: Aguilar and others., doi: 10.1126/science.adx3025.
Birds’ daily and seasonal rhythms are closely governed by shifts between light and dark.
But what happens when these cycles are suddenly interrupted, such as during a total solar eclipse?
Although previous studies have sought to understand the effects of solar eclipses on animal behavior, most have offered only scattered or anecdotal insight into how animals respond.
Indiana University researcher Liz Aguilar and her colleagues saw the April 2024 total eclipse as a rare opportunity to investigate, providing an unprecedented natural experiment on how birds respond to abrupt changes in light.
In anticipation of the eclipse, which cast nearly 4 minutes of daytime darkness over much of the central and eastern United States, they created SolarBird, a smartphone app that allowed users to record the behavior of birds during the eclipse in real time.
Its use by citizen scientists generated nearly 10,000 observations covering 5,000 km of the eclipse’s path.
At the same time, researchers deployed autonomous recording units at sites in southern Indiana, which captured approximately 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 results, out of 52 species detected, 29 showed significant changes in their vocal behavior at some point during the event, but the eclipse did not affect all species equally.
In the minutes before totality, 11 species sang more than usual as the sky darkened.
During the four minutes of darkness, 12 species responded, some going silent while others became more active.
The strongest reactions occurred after the Sun returned, when 19 species changed their songs into what sounded like a false dawn chorus.
Barred owls were calling four times as often as usual, while robins – well known for their pre-dawn songs – were singing six times as fast as usual.
“These patterns suggest that the eclipse temporarily reset the biological clock of some birds, prompting them to behave as if a new day had just begun,” the scientists explained.
Their article was published in the October 9, 2025 issue of the journal Science.
_____
Liz A. Aguilar and others. 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
