Scientists Shed Light on Sea Caves’ Wildlife

After paddling from bright sunshine into a darkened sea cave, it takes a bit for the eyes to adjust. In that moment, other senses sharpen to fill the void.

The damp air feels cooler inside, as the cave exhales to make room for a swell rolling in behind you. The air seems saltier too, so tangy you can taste it. The craggy walls muffle the ocean’s roar, allowing the ears to tune to the sound of waves sloshing softly against roughly hewn rock.

Then the calm is shattered by the furious beating of wings and an alarmed, piercing trill. A pigeon guillemot bolts for the cave’s mouth, leaving its nest behind.

“If you go into a cave with birds flying in and out with fish in their mouth, then there are chicks in there,” explains Paige Martin, a National Park Service seabird biologist. “It’s a good idea to move along and go to the next cave.”

Martin and a team of other biologists and park rangers are leading a guided tour of Santa Cruz Island’s sea caves. It’s not a session for amateurs, but for outfitters and kayak guides. It’s not a session they can afford to miss, because it may determine where they can take their kayaking clients and what places will be off limits.

Ocean kayaking is surging in popularity, up 30% or more a year at Channel Islands National Park. Some of the biggest attractions are the sea caves, each one fascinating in its own way.

At the same time, a few species of seabirds that nest in and around the caves are struggling for survival. One of them, the Xantus’s murrelet, recently became a candidate for protection under the state’s endangered-species law.

Until now, ocean kayaking has been the kind of low-impact sport that fits neatly into the park service’s definition of environmentally benign recreation. Park service officials want to make sure it stays that way.

To that end Supt. Tim Setnicka, former superintendent of Channel Islands National Park, has rounded up kayaking guides and biologists and marooned them on the island -- for a day. In particular, he wants them to be sensitive to the needs of wildlife inhabiting the sea caves that are so popular with kayakers.

“I want to solve this,” he says, “on the basis of guides’ talking to the biologists, one to one.”

Both sides learn that, when it comes to identifying sea caves, they often speak different languages.

Biologists refer to caves by number, such as Cavern Point Cave No. 4. Kayaking guides have their own nicknames for the caves.

One popular cave of many names burrows through an islet attached to Scorpion Rock. Some call it “Birth,” a shortened reference to the narrow rear exit, which is like a birth canal. To slide through the canal, kayakers must lie nearly flat on their backs to avoid getting squeezed against the sloping ceiling and narrowing walls. Some emerge bleeding after brushes with the pitted, barnacle-studded rock, which can shred exposed skin like a cheese grater.

To their relief, biologists and kayakers learn that the caves that attract the rarest birds hold little or no attraction to the guides and their paddling customers.

Bat Cave and Cavern Point Cove Cave -- both “dry caves,” with dry rock or sandy bottoms -- are common nesting sites for the Xantus’s murrelet and the ashy storm petrel, another seabird of special concern.

“We are concerned about people getting out of their boats and walking into these caves,” Martin says. “They may step on birds they cannot see, or step on a log that will crush a bird, an egg or a chick.”

But Eric Little, owner of Aquasports, says his customers are interested in paddling, not awkwardly hoisting themselves out of their boats and walking around in cramped places. “We’re really just interested in the wet caves,” he says.

(Since the meeting, the park service has closed both of the dry caves. It will soon issue a public bulletin with a map to pinpoint the new restrictions.)

Much of the discussion during the day on Santa Cruz Island is spent figuring out what sort of activity disturbs the murrelets, the ashy storm petrels, the pigeon guillemots, brown pelicans and Brandt’s cormorants that nest inside caves and on the rocky cliffs around them.

“If you flush a bird from a cave, is that a disturbance?” Little asks.

“Kayaking is fairly low impact,” says Mike Lamm, co-owner of Channel Islands Kayak Center. “Do you have concerns about noise volume? About people talking?”

The biologists aren’t sure where to draw the line. But they agree that repeated disruptions to nest-sitting, breeding or feeding can make a difference.

“You may not think that you are disturbing them,” says Nora Rojek, a seabird biologist for the California Department of Fish and Game. “But a lot of these birds nest in the same exact crevice year after year. If they are disturbed too many times, they’ll just leave.”

There is no disagreement over what to do about a bird with a fish in its mouth. Move on. The bird is trying to get back to the nest to feed its young.

The guides, all of whom hold permits from the park service, appear eager to do their part. Many of their customers are bird-watchers. Others come to see wildlife and to soak up the beauty of a place that adventure magazines often include in the top 10 kayaking spots in America. So they consider wildlife protection to be in their own self-interest.

Park rangers and biologists remain concerned about kayakers or boaters who set off on their own without licensed guides. The concessionaires agree to help with that too.

“We’re out there all of the time,” Little says. “It’s easy to holler to people and say, ‘Hey, don’t go in there. It’s a federal offense.’ We can’t enforce it, but we can inform the public.”

On the boat ride back to the mainland, Setnicka seems to be pleased with his marooning project. “These guys,” he says of the kayakers, “are going to be warriors for the wildlife.”