​Can seabirds detect infrasound? And if yes, do they use it to navigate the vast oceans?

A physiological ecologist from Stellenbosch University (SU), Dr Susana Clusella-Trullas, will be charting unsailed waters as she sets out to answer this question in collaboration with a team of researchers from the USA, the United Kingdom (UK) and The Netherlands.

They have recently obtained a grant of R1.3 million from the International Human Frontier Science Program as part of its Young Investigator Grants for research into complex mechanisms of living organisms.

Seabird migration remains one of the phenomena in the animal kingdom that we still know very little about. Over the years scientists have managed to prove that some birds use the position of the stars and the earth’s magnetic field to find their way. More recently, a group from the universities of Oxford, Barcelona and Pisa, demonstrated that shearwaters rely on their sense of smell to find their way back to their nests on land after foraging out over the ocean.

Dr Clusella-Trullas will be working with Jelle Assink, a geophysicist from the Royal Netherlands Meteorological Institute in The Netherlands; Samantha Patrick, a behavioral ecologist from the University of Liverpool in the UK; and Mathieu Basille, a spatial ecologist from the University of Florida in the USA.

The idea is to pool all their expertise in order to tackle this vexing question from every possible angle.

“As the physiological ecologist in the team, I will be examining the ear structures of various seabird species to test this hypothesis. Since some seabirds have tremendously long migrations, it is highly possible that they use infrasound as a medium to orientate, avoid storms and detect island shores. There are a few studies that suggest that homing pigeons can detect infrasound and some structures and mechanisms have been described for this group,” she explains.

As seabirds are often found as by-catch in fisheries, she will be obtaining fresh carcasses from various sources to do the research: “We will examine cross sections of the inner ear of these seabirds. Hopefully we will be able to identify the mechanisms that allow them to detect infrasound.”

As part of this process, she will also use 3D imaging techniques to look for the structures.

If they are able to identify the mechanisms that allow seabirds to detect infrasound, these will then be visualised and measured. The data will then be integrated by means of spatial modelling with data from the larger international collaborative project.

For more information about the project and their progress, visit the blog at https://seabirdsound.wordpress.com/

On the photo above, Dr Susana Clusella-Trullas from SU's Department of Botany and Zoology. Photo: Stefan Els