Sinister river otters caught hunting and drowning majestic California birds

Their otter-ly ruthless.

River otters have been ambushing brown pelicans at a picturesque Northern California lagoon — dragging the massive birds underwater, drowning them and feasting on their dead bodies.

Researchers counted a staggering 73 dead pelicans during a single season at Abbotts Lagoon in Point Reyes National Shore, where as many as 300 of the birds could be seen resting at one time, according to SFGATE.

The gruesome hunting tactic was recently thrust back into the spotlight after wildlife photographer Daniel Dietrich shared footage captured in 2023 showing otters taking down two pelicans.

Dietrich said in the caption of his video post that he believed it to be the first time the act had been caught on camera.

But wildlife researcher Megan Isadore witnessed the bloodthirsty attack firsthand years earlier.

Isadore, co-founder of the River Otter Ecology Project, was watching wildlife at the lagoon in 2018 when she spotted a brown pelican frantically flapping its wings.

The struggling bird’s head suddenly disappeared beneath the surface — before an otter emerged and began eating it.

“I realized the otter had grabbed the pelican, killed it by drowning it, and was starting to eat it,” Isadore told SFGATE.

She and the other witnessed were “somewhat horrified,” she recalled.

Isadore later began finding an increasing number of pelican carcasses scattered along the lagoon’s shoreline, prompting her and fellow project co-found Terence Carroll to investigate.

The pair monitored the lagoon from June through November 2023, marking each carcass with a biodegradable marker to avoid counting the same bird twice and recording measurements to determine the victims’ ages.

Most appeared to be younger birds, Carroll told the outlet.

Their findings were published in April 2025 in the IUCN/SSC Otter Specialist Group Bulletin.

Although 73 deaths was “more than we’d ever seen before,” Isadore said the toll was not large enough to threaten the broader brown pelican population.

The attacks are still considered exceptionally rare.

Before the Point Reyes killings, similar behavior had been reported at Northern California’s Rodeo Lagoon in 2006 and Lake Tolowa in 1998. It has not been document outside the Golden State, according to SFGATE.

Researchers previously suspected excessive algae growth at Rodeo Lagoon had depleted fish stocks and forced hungry otters to turn to pelicans.

Abbotts Lagoon, however, has not experienced the same conditions — raising the possibility that its otters simply discovered the bulky birds made an irresistible meal.

“Pelicans are big and have a lot of meat on them,” Isadore told the outlet.” It’s a lot of bang for their buck.”

Despite their playful, puppy-like appearance, river otters are opportunistic predators with high energy needs and regularly hunt ducks, gulls, cormorants, fish and other aquatic prey.

“They’re very fierce and hungry little animals,” Isadore said. “They’ll get whatever’s plentiful and easiest to catch.”

The otter’s reign of terror may already have changed the pelicans behavior.

Isadore reported seeing pelicans fly away when otters approached — believed to be the first documented avoidance behavior between the two species.

Dietrich also said far fewer pelicans now venture into the lagoon, even though they remain common elsewhere around Point Reyes.

The photographer believes the bloodshed has largely subsided since peaking several years ago, possibly because the birds learned to steer clear of the danger zone.

“They just give it a miss, or they circle and then keep going,” he told SFGATE. “It is amazing.”

Researchers still do not know how the gruesome hunting tactic spread between otters — or why the killings later tapered off.

Whatever happened beneath the water at Abbotts Lagoon, however, the surviving pelicans appear to have gotten the message: This is one splash zone worth skipping.

Download The California Post App, follow us on social, and subscribe to our newsletters