Headstands and bubble blasts: Drones show gray whale foraging on Oregon Coast

Researchers have discovered new insights through drones on the acrobatic foraging techniques of gray whales off the Oregon Coast, according to Oregon State University's Marine Mammal Institute.

For seven years, researchers have patrolled the area between Seal Rock and Depoe Bay by boat to spot the plume of water from a whale's surface breaching spout.

The whales are part of the Pacific Coast feeding group of gray whales, according to Clara Bird, a researcher in the Marine Mammal Institute's Geospatial Ecology of Marine Megafauna Laboratory.

"The Pacific coast feeding group is a subgroup of the eastern north Pacific population," Bird said. "Most of the gray whales that migrate along the coast winter in Baja California, Mexico and then migrate all the way north to the arctic waters off Alaska for the summer. This little subgroup, for reasons we don't know, stops to feed all summer off the coast of the Pacific Northwest."

Behavior change comes with age for gray whales

After reviewing drone footage, Bird and fellow researchers determined the whales' movements — including forward and side-swimming, headstands and "bubble blasts" — change as the whales grow and age.

Younger and smaller whales are more likely to use forward swimming behaviors when foraging. Older, larger whales are more prone to perform a headstand and push their mouths into the ocean floor.

“Our findings suggest that this headstanding behavior requires strength and coordination. For example, we often see whales sculling much like synchronized swimmers do while they are headstanding. It is likely this behavior is learned by the whales as they mature,” said Bird, who led the research as part of her doctoral dissertation. “We have footage of whale calves trying to copy this behavior and they’re not able to do it successfully.”

The original thinking behind the bubble blast — a single big exhale while they’re underwater that produces a large circle pattern at the surface — was that whales used it as a way to aggregate or capture prey. The new study shows that whales use it as a way to regulate their buoyancy. The larger and fatter a whale is, the more likely they are to bubble blast, especially while performing headstands or long dives.

“It is just like when we dive underwater, if we release air from our lungs, then we can stay underwater more easily without fighting the buoyancy forces that push us back toward the surface,” Bird said.

Oregon Coast is a hot spot for whale watching and research

An estimated 18,000-plus gray whales now live in the eastern north Pacific area, according to Oregon State Parks . About 30 whales per hour cruise past the Oregon Coast during southbound migration in late December and about six per hour on the northbound trip in early May.

Of the Pacific feeding group, a roughly 200-member subgroup of whales spend the summer feeding off the cliffs of the Oregon Coast.

Fortunately for researchers, there hasn't been too many days when they don't see any whales, Bird said. On an average day, the crew spots between eight to 10, but the record is around 32 whales in single day.

“Because these whales are feeding close to shore, where the water is shallow and we can capture their behavior on video, we’re able to really see what is happening,” Bird said. “To be able to study the whales, in our backyard, and fill in some answers to questions about their behavior, feels very special.”

"Drones have completely revolutionized marine mammal science"

With the advancement of drone technology, Bird and fellow researchers have been able to make discoveries not feasible over a decade ago.

"It's not just the behavior," Bird said about the viewpoints drones provide. "The first question we used a drone to answer was 'how big is that whale?' Which is a super basic question, but for something as big as a gray whale, we can't answer that question unless that whale is dead without drones."

Observations like feeding behaviors, size measurements over time and tracking health by seeing how fat the whales are became possible by the implementation of drones.

"Drones have totally changed the questions we can ask and expanded our capabilities," Bird said.

The research completed by Oregon State's Marine Mammal Institute was used in two academic papers. Foraging tactics can be found in the journal Animal Behavior and bubble blast behavior was published in the Ecology and Evolution .

Elliott Deins is an outdoor reporting intern for the Statesman Journal. You can reach him at edeins@salem.gannett.com

This article originally appeared on Salem Statesman Journal: Headstands and bubble blasts: Drones show gray whale foraging on Oregon Coast