Albatrosses are known for their remarkable long-distance migrations and expansive foraging journeys. These seabirds spend most of their lives soaring over the open ocean, traveling vast distances in search of food.
Albatrosses can cover thousands of miles during their migrations and often traverse entire ocean basins. They can circle the Southern Ocean multiple times in a single year.
In a study from the University of Liverpool, researchers have unveiled new clues in how these massive migrations are executed.
The study has produced the first evidence indicating that wandering albatrosses might employ infrasound as a navigation tool.
The term “infrasound” refers to sound frequencies that fall below the range of human audibility. It’s a low-frequency sound that is omnipresent in marine environments.
One significant source of this infrasound is microbaroms, which are a class of atmospheric waves generated by the collision of ocean waves. Microbaroms are also known as the “voice of the sea.”
Interestingly, regions with these colliding waves often experience strong winds, which play a crucial role in aiding the albatrosses’ efficient flight.
The researchers set out to understand the potential link between albatrosses and their use of infrasound for navigation. They deployed GPS trackers to chart the flight routes of 89 wandering albatrosses that breed in the Crozet Islands archipelago, located in the Southern Ocean.
By comparing the tracked flight paths with acoustic maps specifically modeled for this study, which depict the distribution of microbarom infrasound, the team made an intriguing discovery.
The data shows that when embarking on directed flight segments, wandering albatrosses display a tendency to head towards areas where microbarom infrasound is pronounced.
This behavior suggests that these birds might possess the capability to detect and react to microbarom infrasound even when it’s disseminated over vast distances.
The study was jointly led by Dr. Natasha Gillies, a seabird ecologist with the University’s School of Environmental Sciences, and Dr. Lucía Martín López.
“How animals navigate and search for resources over large spatial scales exceeding 100s-1000s km is a fundamental question in ecology,” said Dr. Gillies.
“For marine animals, such as seabirds, this question is especially intriguing due to the limited availability of visual information, meaning that other cues must be involved in movement.”
“It has been proposed that seabirds could use infrasound to help them navigate the huge expanses of featureless ocean environment that they fly over in order to forage.”
“Our results offer the first evidence for responsiveness to infrasound in a movement context for a free-ranging animal.”
The research is part of a Human Frontier Science Program grant, which brings together an international team of collaborators (Stellenbosch University in South Africa, University of Florida, Royal Netherlands Meteorological Institute in the Netherlands).
“It is only through interdisciplinary science like this, which brings together scientists across diverse fields, that we can achieve such new and exciting insights,” said Dr. Samantha Patrick, who led the grant.
The study is published in the journal Proceedings of the National Academy of Sciences.
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