A Professor’s Passion: Studying Otter Behavior

Author: Whidbey Camano Land Trust | 07/31/19
       

North American River Otters

North American River Otters take a break from foraging for food in Admiralty Bay. This particular kinship group has been studied closely by Dr. Heide Island for the past year. She even has names for them: from left to right, Crest, Swoosh, Patches, and Slash (face obscured). Photo by Heide Island.

Land Trust’s Crockett Lake Preserve is one of settings for research

For nearly a year now, a psychology professor from an Oregon university has dedicated herself to studying the foraging choices and other behaviors of a population of river otters on central Whidbey Island.

Dr. Heide Island, a comparative animal behaviorist from Pacific University in Forest Grove, rises as early as 4 a.m. most days for the opportunity to observe Whidbey Island’s North American river otters.

She observed a family of these otters that eat, sleep and play in and around Crockett Lake Preserve next to Admiralty Bay last September and has been studying them there since. Dr. Island received a year-long sabbatical in September of 2018, referring to it as a rare field opportunity to study an elusive mammal since they are most active around dawn and dusk.

Heide Island talks

Dr. Heide Island gives a presentation on North American River Otters in front of about 140 people at the Coupeville Rec Hall on July 17, 2019.

“Almost all research of river otters is on diet and distribution and thereby, scat sampling, so the fact that I’ve had a full year to do in-field observation, and consistently observe a resident population as well, has been a joy and an honor. It has also allowed me to photo identify a total of 12 different otters this year.”

She’s gotten to know a particular kinship group and one newcomer to the mix, as well. In fact, she has names for all five of them.

River otters’ individual identifications are based in part, on unique coloration patterns on the muzzle. These markings provide the basis for most names. The four Island has consistently observed over the year are a kinship group comprised of Patches and her three pups: Crest, Swoosh, and Slash. There’s also a fifth otter, Handsome, who came on to the scene in March during mating season.

“His name is my husband’s fault,” Island said, noting that Handsome’s name does not describe the muzzle markings. “While Tom was visiting, he came out to observe the otters with me and given Handsome’s healthy size and pelage, he said, ‘Now, that’s a handsome otter.’”

Island shared these tales and other findings during a presentation in front of about 140 people at the Coupeville Recreation Hall on July 17. The talk was organized by the Whidbey Camano Land Trust, which has granted Island access to Crockett Lake Preserve to study the otters there. They spend a significant time foraging and nesting on parts of the preserve, which also contain a number of den sites.

“They’re an indicator species. Essentially, they’re an ecological canary in the coal mine. They are the first species to die if there are contaminants in a watershed, so the healthy of your river otters is indicative of the health of the habit.” — Dr. Heide Island

Island had intended to spend her sabbatical at a research station on Blakely Island in the San Juans but found the established river otter population there was gone. She then visited central Whidbey Island and discovered an ideal place in Admiral’s Cove, a community located next to Admiralty Bay and the expansive Crockett Lake wetland preserves.

Despite their name, river otters live in a variety of habitats and hunt for food in both marine and freshwater systems. North American river otters are more abundant, about half the size, and spend more time on land than the Northern Sea Otter, Washington’s only other otter species. While river otters are considered a least-concern species, sea otters are endangered and the only place they’re consistently found in Washington is along the Olympic Peninsula.

“So, you may be wondering, ‘Why do we care about a least-concern species?’ Island said during her presentation. “Aside from the obvious that they are adorable, there are a number of reasons why we should care. First, they’re an indicator species. Essentially, they’re an ecological canary in the coal mine. They are the first species to die if there are contaminants in a watershed, so the health of your river otters is indicative of the health of the habitat.”

River otters also are considered a keystone species in which other species are dependent. Herons and eagles, for instance, dine on river otter leavings.

Foraging Otter

A river otter forages for food in Admiralty Bay. Photo by Heide Island.

Island’s research has focused on the otters’ foraging patches between fresh and saltwater environments and their foraging choices by season, tidal activity, current, and time of day. She studies how frequently they forage, what techniques they use, their “giving up time” at each patch, and what they eat in the bay compared to the brackish lake in Admiral’s Cove.

“I was especially interested in was their diet,” Island said. “Published literature of river otter diet on San Juan Island suggested in addition to a variety of other fish, their diet comprised two endangered species of rock fish (one has since been delisted) as well as salmon species. But based on over 80 scat samples from otters in Admiral’s Cove, their diet does not include a single salmonid or rockfish species. The bulk of what they are eating here is sculpin and flatfish.”

She’s called her experience on Whidbey Island “enchanting” and is planning to be back monthly. This was only the first year of a five-year longitudinal study on Whidbey that she hopes will include Pacific students and local citizen scientists next summer.

Island is both fascinated and amused by the otters’ behaviors. She’s watched Patches and her three pups hunt for food on the sea floor as a cohesive unit. She’s seen Handsome employ a hunting technique using air bubbles to scare fish to the surface.

She’s seen the otters groom each other and engage in a funny “latrine dance” when nature calls.

“I could cry thinking about leaving in August,” Island said during her presentation. “This place is so much more like home than home. It’s largely because the community of people here are incredibly supportive. They’ve been so interested in the otter research and in conservation of their habitat. I’m incredibly grateful and honored to be working with the Whidbey Camano Land Trust and to be part of the community, because you folks are incredible.”

After she returns to Oregon to teach in mid-August, she plans to return to Whidbey once a month to check cameras, otter latrine sites, collect specimens, and visit with island residents she’s met who have otter dens on their properties. She will also speak at Sound Waters University on Whidbey in February of 2020.

“Alaska is where I grew up and once an Alaskan, always an Alaskan,” Island said. “But I have not called Juneau home in a long time. I suppose what I meant when I said Whidbey feels more like home than home is this: I live in Portland, I work in Forest Grove, but Whidbey is home to me now.

“It seems to me that Whidbey chooses you. The island decides that you fit here and it claims your spirit.”

You can also find an automated data sheet on her website.

The above video was captured by one of Dr. Heide Island’s remote cameras during her study of North American River Otters on central Whidbey Island. The otters are demonstrating the “latrine dance,” a dance they do when nature calls. Video courtesy of Dr. Heide Island.