Odd Bird Rescue

In the early 2000s, Keith Bensen, a wildlife biologist at Redwood National and State Parks, wanted to find out whether the noise produced by chainsaws and other equipment was pushing out marbled murrelets, a rare robin-sized species that nests in the park.

This might sound straightforward enough, but it was anything but, and it turned into one of the park’s most expensive wildlife research projects ever conducted.

Murrelets are seabirds that through some quirk of their evolutionary history decided to nest high up in coastal redwoods and other old-growth trees rather than on the cliffs favored by their puffin cousins. Murrelet nests are completely invisible from the ground, and Bensen had no idea where to find them. So the park collaborated with outside scientists to capture about 80 of the birds at sea, equip them with radio transmitters and eventually canvass the park with handheld receivers, trying to locate signals in the dense forests. They sent tree-climbing biologists some 200 feet up to follow up on leads, but murrelets use little nesting material, and their brownish summer plumage makes them nearly impossible to spot. Three years of efforts led the team to only a couple of nests.

“They’re doing everything they can to hide, which makes them a real pain to try to find and study,” Bensen said.

Murrelets are endangered globally, and their worldwide population is in decline. Redwood, which might be home to as much as 90% of the nesting murrelets in California, plays an outsized role in the species’ survival, so Bensen feels a heightened sense of responsibility to do all he can to help the birds. “A lot of folks pay attention to us when it comes to marbled murrelets,” he said. For the past quarter century, Bensen and others have gone to great lengths to gather “dribs and drabs” of data about this mysterious bird and make management decisions based on what they gleaned. “Sometimes the best available science is almost none, but that’s what you’ve got,” he said.

As part of that noise study, the team set up cameras near the nests. It confirmed that noise could bother the birds, so the park started scheduling trail maintenance outside the nesting season. The photos also surfaced another, bigger problem: In some images, Steller’s jays were feasting on murrelet eggs. “We were like, ‘Oh geez, this might be an issue!’” Bensen said.

The location of the murrelet’s nesting grounds was one of the last great ornithological mysteries in North America until 1974 when, as the story goes, a maintenance worker trimming a tree in Big Basin Redwoods State Park caught an odd sight — a nesting forest bird with webbed feet. With the nesting puzzle solved, scientists immediately understood the species’ predicament: Only fragments of the Pacific Coast’s old-growth forests remained after a century of intense logging. The murrelet’s odds improved in 1994 with the enactment of the Northwest Forest Plan, which has helped protect old-growth forests from logging on federal lands in California, Oregon and Washington. But the crisis isn’t over: Logging goes on elsewhere, and intense wildfires have claimed part of the bird’s nesting range, said Jim Rivers, an associate professor of wildlife ecology at Oregon State University.

Murrelets are split-habitat birds, but unlike migrating creatures, they rely on both habitats — the ocean and the coastal forest — at the same time. Adults fly back and forth between the nest and the ocean to catch fish and feed their lone chick. During a marine heat wave a few years ago that reduced the availability of food off the Oregon coast, Rivers and his colleagues found that most murrelets left the area and none of them nested nearby. These were anomalous conditions, but the trend toward warmer ocean temperatures doesn’t bode well for the murrelet. In other words, the split-habitat strategy “puts them in double jeopardy,” Rivers said.

Warming oceans can only be addressed by a global climate change response, but land managers can act to improve murrelet habitat on the ground. So, when it became clear that Steller’s jays posed a major threat to murrelet reproduction, park staff worked to learn more about these common, yet not well-understood, corvids. They set out to count Steller’s jays and also ravens (which occasionally prey on murrelet eggs) in various parts of the park and partnered with graduate students who radio-tagged a few of the predator birds. The group found that jays, attracted by food left by visitors, congregated around the park’s campgrounds, endangering murrelets in those areas.

In talks and on signs, park staff provided abundant context to visitors about why they needed to secure their food, but the messaging wasn’t effective. “Most folks, they’re here to recreate, enjoy themselves, relax, be in nature and not, you know, get another degree in biology,” Bensen said. So, he commissioned a team from a local university to survey, interview and observe park visitors around attitudes toward murrelets, jays and ravens. While most visitors seemed to agree that it was important to protect murrelets and that feeding jays was bad, the researchers found that few visitors even knew what murrelets were, and the team saw quite a few children feed jays directly. Some of the team’s recommendations: prioritize written messages, be direct and keep it short. “If your message is like, five paragraphs long, you can forget it,” said Carolyn Widner Ward, who co-led the Redwood study and has conducted similar work at Petrified Forest National Park to discourage visitors there from stealing petrified wood.

As a result, staff came up with their “Keep It Crumb Clean” slogan, which they plastered all over the park. The strategy seemed to work: The density of Steller’s jays at campgrounds dropped by half. (Bensen also tested a technique that involved injecting fake murrelet eggshells with a substance that would make Steller’s jays throw up — and keep them from preying on the birds’ eggs. The experiment worked — and garnered attention from the global media — but Bensen decided that, for now, it’s impractical to deploy this approach.)

Meanwhile, Bensen has kept trying to find more nests. He trained staff to look for murrelet eggshells, and he contracted dogs trained to detect fishy aromas in the woods. More often than not, the person tasked with actually locating the nests in the trees’ crowns based on these ground-level clues was Jim Campbell-Spickler, a wildlife biologist who’s been to the top of Hyperion, considered the tallest tree on Earth, and has ascended countless other giants. He’s also climbed some 1,500 tall trees for murrelet research and has become an expert at identifying nest sites based on subtle signs such as the shape of the branches or traces of feces. “You have to use your instincts,” he said. “It’s really detective work in the sky.” The latest batch of cameras have yielded some discoveries, such as images of a Humboldt’s flying squirrel chasing a couple of murrelets off their nest. Last year, Bensen and his team were elated when footage showed an egg coming out of a female’s cloaca, but their hopes were soon dashed when a large raven came into view, pierced the eggshell with its beak and gulped down the yolk.

The overall picture is more positive, though. Population estimates are conducted at sea regularly, and the most recent one showed that murrelet density in the zone offshore from Redwood was increasing. While there is no way of knowing whether that uptick is due to Redwood’s decades-long conservation efforts, Bensen views the data point as a win.

“At least we’re not completely blowing it,” he said.