Understanding changes in the direction and speed of ocean currents is useful for understanding the effects of climate change. Typically the spatio-temporal variability of sea currents is measured through obtaining remotely sensed ocean wave data coupled with measurements from drifting buoys, gliders, and high-frequency radar. A group of researchers wanted to test if drifting seabirds could offer a novel way of collecting data about sea current velocity and direction. To test their theory, the researchers attached GPS trackers to 75 Scopoli’s shearwaters (Calonectris diomedea).
The study site was the Balearic Sea located in the Mediterranean Sea where the Scopoli’s shearwaters tend to drift on the ocean surface during foraging, known as rafting behavior.
While less than 10% of the seabird’s time is spent rafting, 405 trajectories were collected, and of those, 85% were spent drifting on the ocean surface for up to 6 hours at a time. Researchers concluded that ocean surface currents and local winds were the dominate influences in Scopoli’s shearwater drift movements.
After comparing seabird rafting trajectories with satellite-derived ocean velocity data, the researchers concluded that their study demonstrated “the potential of seabird drift movements to monitor surface currents and mesoscale features in the Balearic Sea.”
While this approach to tracking sea currents would not replace current satellite/in situ measurements, using tracking technology from seabird behavioral studies could supplement sea velocity data.
The study:
Sánchez-Román, A., Gómez-Navarro, L., Fablet, R., Oro, D., Mason, E., Arcos, J. M., … Pascual, A. (2019). Rafting behaviour of seabirds as a proxy to describe surface ocean currents in the Balearic Sea. Scientific Reports, 9(1), 17775. https://doi.org/10.1038/s41598-018-36819-w
