Credit: CC0 Public Domain
Isn’t it amazing how far animals can travel looking for food? While caribou, reindeer, and wolves cover impressive amounts of ground, seabirds are unparalleled in their traveling distances. Arctic terns are known to travel from the Arctic to Antarctica and back as part of their annual migration, and wandering albatrosses (Diomedea exulans) fly the equivalent of ten times to the moon and back over their lifetimes.
Extensive research has focused on understanding how seabirds choose their flight paths and find food. It appears that seabirds use their sight or sense of smell to evaluate local conditions.
Wandering albatrosses can travel more than 10,000km in a single foraging trip, and researchers are eager to learn about how these birds use mid- and long-range cues from their environment to decide where to go.
For the first time, however, my team’s recent study provides insight into how birds such as wandering albatrosses may use sound to determine what conditions are like further away.
How seabirds use low-frequency sound
Previous research has shown that seabirds not only seek information about where to find food, but how to do so efficiently. We discovered that the way wandering albatrosses use their sense of sound may be crucial.
Our study looked at how these birds respond to a very low-frequency type of sound called infrasound, which can travel for thousands of kilometers.
Despite the fact that infrasound is typically inaudible to humans, it is known that some animals can hear infrasound. When waves crash together or against coastlines, they create a frequency of infrasound called microbarums, which was the type of infrasound our study focused on.
Areas of high wave activity can be associated with upwellings—where fish are brought to the surface. Infrasound could provide information about where these areas are and inform birds of good foraging patches.
Efficient foraging is particularly important for large seabird species like the wandering albatross, which have a wing span of 3.5 meters. Their size means they rely on wind to take off and fly efficiently, unlike smaller birds such as puffins, which flap their wings up to 400 times a minute.
High wave activity also indicates strong winds. Given we know that wandering albatrosses depend on wind to fly efficiently, my team’s study suggests that infrasound could give them a long-range cue for where optimal foraging conditions may be.
Another interesting point is that infrasound is also generated when waves crash against coastlines. Many coastal seabirds use the coast to select their flight paths and find their way back to their breeding colonies. Therefore, infrasound could reveal the location of static features like coastlines, giving seabirds important information across long distances.
Despite the potential of this cue for seabirds,