Could the Corvid Conservation Corps Replant a Forest After Fire?

Island Scrub-Jays are acorn-planting machines. Flying foresters might be just what today's scorched Western landscapes need.

The bird flares blue as gas flame. It seems to dive, not fly: Two flaps, a tuck tilting to full fall, all grace and faith and then the sure catch of its wings rocketing it up, before another plunge lands it swaying on a branch.

It鈥檚 an Island Scrub-Jay, cousin of the California Scrub-Jays common at mainland feeders, but found only here, on Santa Cruz Island, the largest of the eight Channel Islands off Southern California. The azure bird has white brows, a gray vest, and a broken V striped across its white breast like a shirt collar. It scolds the three women who have summoned it on this January afternoon鈥PASHPASHPASH!鈥攍ike a dapper old man grumpily demanding dinner.

Carina Motta is counting on this boldness. She presses her lips together in an approximation of the jay鈥檚 scold, calling it to a wooden platform loaded with acorns from the island scrub oak. The jay obliges by winging the seeds away and tapping each into the earth with its beak.

Feeding animals in the wild is generally frowned upon. But this particular interaction may offer a gentle shortcut for restoring oaks to damaged landscapes where they once stood, including the field where Motta now crouches with Minerva Rivera and Evelyn Bobadilla.

The three women are undergraduates working with , a scientist at the Smithsonian Migratory Bird Center, and , a researcher at the center and the Cornell Lab of Ornithology. They鈥檙e using feeding platforms to lure jays from intact scrub oak onto recently burned land, hoping the birds will deploy their special talent there.

Island Scrub-Jays, like many other corvids, are 鈥scatter hoarders.鈥 Oaks produce acorns each fall, and the birds cache up to 4,500 each鈥攆ar more than they eat. Those acorns that survive winter undevoured have a shot at becoming trees. When naturalist Joseph Grinnell observed California Scrub-Jays carrying acorns far uphill from oaks in the Sierra Nevada in 1935, he saw the 鈥渓ocomotion of the whole forest鈥 borne aloft on birds鈥 wings.

The goal on Santa Cruz is to direct that locomotion, creating 鈥渓ittle islands of oaks,鈥 Motta says, and speeding the woodland鈥檚 march across the burn scar. It鈥檚 not a farfetched idea. After the last Ice Age corvids are thought to have accelerated the spread of North American beech and oak northward on the tails of retreating glaciers. In Germany, foresters have taken advantage of jays鈥 planting by preserving massive oaks and providing additional acorns in baskets. In an urban forest in Sweden, researchers estimate that it would cost up to $3,800 per acre annually to hire humans to do what Eurasian Jays do for free.

The Santa Cruz study, now in its second season, will take several years to show whether enlisting jays is a viable restoration tactic. If it and similar studies bear out, they could suggest new ways to tap landscapes鈥 native healing powers, as practiced by their wild inhabitants, and stretch scant conservation funds farther. 鈥淭hat鈥檚 a really exciting possibility,鈥 Sillett says.

Just imagine what the birds could contribute if we carefully guided their skills.

There鈥檚 no shortage of places that need help, and California is high among them. The state has lost more than 30 percent of its oak woodlands, mostly to development. And though oaks are adapted for fire, climate change is driving more intense and frequent wildfires that can kill mature trees and even transform oak habitats into shrublands or grasslands. After 2017鈥檚 North Bay fires, Californians joined acorn drives and planted oak seedlings to stabilize soil, beat back invasive plants, and restore bulldozed woodlands in areas they share with scrub jays. Just imagine what the birds could contribute, Sillett suggests, if we carefully guided their skills. 鈥淵ou walk along these incredibly rugged landscapes of California, and it becomes quickly apparent to anybody that if you had a little blue seed-dispersing robot, that鈥檚 way more efficient than us lumbering around.鈥

The Channel Islands certainly count among California鈥檚 most rugged, and most altered, landscapes. In the 1800s, ranchers introduced tens of thousands of livestock including sheep, cows, and pigs to ecosystems unaccustomed to grazing; soon, grassland and barrens replaced oak chaparral and woodlands. By the time The Nature Conservancy purchased most of Santa Cruz in 1978, 10 plant and animal species were near extinction, and feral pigs and sheep ran rampant.

After the sheep were removed in the 1980s and acorn-eating pigs by 2006, native habitat rebounded: Santa Cruz鈥檚 scrub oak increased by 50 percent, right along with what Sillett鈥檚 work suggested was a 20 to 30 percent increase in jays. Other researchers found that the trees鈥 expansion was consistent with the jays鈥 seed-dispersal range. 鈥淭hat got us thinking, 鈥楥ould the jays have been their own accidental gardeners, and recovered their own habitat?鈥欌 Sillett says. And, if so, would it be possible to enhance that process?

Decades of similar work from tropical forests offer some insights. These complex systems host hundreds of tree species, and the majority rely on animals to move their seeds around. It generally isn鈥檛 logistically or financially feasible for people to replant them at large scales. 鈥淩estoring the processes and attracting the dispersers makes the most sense because then the ecosystem can be self-sustaining,鈥 says Karen Holl, a University of California, Santa Cruz researcher who studies forest restoration in Costa Rica.

That elegant approach is more complicated than it sounds. Many scientists have tried to jumpstart natural recovery by erecting artificial perches and nest boxes in abandoned pastures to attract birds and bats, which then poop out seeds they鈥檝e eaten in intact habitat. But invasive grasses often outcompete new seedlings, halting forest recovery before it begins. Instead, planting a tree, or islands of trees, can provide a seed source and attract animals while shading out grasses, letting seedlings take root.

Seed dispersers鈥 helpfulness also depends on their numbers, and how much of their original habitat remains to provide seeds. In Brazil鈥檚 fragmented Atlantic Forests, where both native dispersers and habitat are limited, Wesley Silva of the Instituto de Biologia, UNICAMP, studies how feeding stations might turn whatever animals are available鈥攊ncluding invasive ones like marmosets鈥攊nto restoration 鈥渃ollaborators.鈥 His vehicle of choice? Bananas packed with native seeds. The animals 鈥渁re very fond of bananas,鈥 he says. It is 鈥渢he universal fruit.鈥

Because trees grow slowly, these techniques take time to produce results. In the western United States, for instance, scientists are planning a multicentury restoration strategy for whitebark pines where Clark鈥檚 Nutcrackers will be 鈥渄oing the heavy lifting,鈥 says biologist Diana Tomback of University of Colorado-Denver. Blister rust from Asia is wiping out the trees, alongside pine beetles and fire suppression. Agencies have spent decades collecting seeds, cultivating them, and screening seedlings for resistance to the fungus. Once they plant those whitebarks, they will lean on the birds to spread their seeds鈥攁 literal resistance movement. 鈥淚t鈥檚 going to take a few human generations to get this done,鈥 Tomback says. 鈥淟et鈥檚 hope someone has a good attention span.鈥

Sillett and Pesendorfer didn鈥檛 need a multi-颅generational commitment; they needed a study site. Then, in March of 2018, managers lost control of a fire they had set on Santa Cruz to dispose of invasive trees. The flames licked through 260 acres of invasive fennel, then singed into scrub oak: a perfect margin from which to coax the accidental gardeners.

Island Scrub-Jays are not always amenable to coaxing, and on the second morning of the crew鈥檚 January field visit, Motta is having an understated faceoff. She walks with an acorn held aloft between thumb and forefinger, pishing over her shoulder at some stationary birds.

鈥淵ou kind of have to build a relationship with them,鈥 she explains.

鈥淚f we don鈥檛 have trust,鈥 Rivera adds, 鈥渨e don鈥檛 have anything.鈥

Gentle and sharply intelligent, Motta describes herself as a little old lady trapped in a 22-year-old鈥檚 body. She perfected her avian sound at a 鈥減ishing workshop鈥 she attended solo in high school. At University of California, Santa Barbara, she was heartened to meet peers who racked up bird sightings the way others might accrue vinyl records. Still, she was not a collector so much as an admirer of beautifully interrelated things, and she soon resolved to study the ways animals and plants build worlds together.

The jays eye Motta skeptically, and she and the others change tack, throwing sterilized acorns into the grass as if chumming water to attract sharks. Finally, a pair descends on the feeding platform.

In past experiments, Pesendorfer and Sillett planted radio tags inside acorns to track how they fared. But the birds tossed all aside, 鈥渓ike, 鈥楾o hell with this. This is bogus,鈥欌娾 Sillett says. It shouldn鈥檛 have been a surprise: Jays favor solid acorns over those riddled with insect tunnels, which, along with the birds鈥 habit of stashing seeds under protective brush, leads more to sprout. Now Motta, Rivera, and Bobadilla rush to follow the jays鈥 movements with more analog tools鈥攂inoculars, rangefinder, and GPS鈥攕etting waypoints for every acorn stashed. The women are part of the , which connects underrepresented students from local colleges with opportunities like this one.

The hope is to fill platforms with seed and walk away鈥攁 set of restoration bird feeders.

Six platforms stand inside the burn scar, each adjacent to the likely territory of a mated jay pair. Jays are mad for peanuts, so the crew used them to train the birds to see the platforms as food sources. Though they鈥檙e starting small, with 10 acorns per station per visit, the hope is to fill platforms with seed and walk away鈥攁 set of restoration bird feeders.

The crew鈥檚 island weekends unfold in a series of comedic dramas. There is backseat stashing, one jay re-hiding caches when its mate looks away. Others gulp three at once, gaping like gluttons. Sometimes, Motta says, the crew pishes for 15 minutes before realizing the jays are perched behind them, watching. In those waiting moments, it is quiet enough to hear the stroke of ravens鈥 wings鈥攁 sound Bobadilla loves. To her, the birds鈥 proximity is something from a Disney movie. 鈥淚鈥檓 telling you, I feel like Cinderella,鈥 she exclaims after a hummingbird circles her head.

When the crew returns in May, there are green shoots鈥斺渙ur children,鈥 Motta dubs them. They are unimpressive in stature, but made wondrous by the mechanism of their arrival. Eighteen baby oaks push up into the fire scar near the platforms. In sites where the crew didn鈥檛 feed birds, they find only one. Though the birds flew most of the seeds back toward the scrub oak, rather than farther out into the open, they hid more than 80 percent of the acorns within the burn scar.

By October a freshly graduated Motta has returned to the island to oversee a new crew as they fine-tune the study methods. This time, they鈥檒l use chains of two platforms at each site to draw jays deeper into the scar and supplement acorns with toyon berries and islay cherries, both native shrubs that could shelter oak seedlings.

Ultimately, it will be critical to assess feasibility. 鈥淲hat鈥檚 the cost per germinating acorn that鈥檚 put out there by a human versus put out by a bird?鈥 Sillett asks. And how likely is each to become a tree? Oak reproduction is fickle, adds Liv O鈥橩eeffe, senior communications director at the California Native Plant Society, which is leading an effort to 鈥淩e-Oak California.鈥 Acorns are viable for only a season, and seedlings die for countless reasons. 鈥淎nything we can do to improve the odds of an oak tree is important,鈥 O鈥橩eeffe says, so it may be best to encourage jays to help human planters rather than replace them.

Regardless, there鈥檚 already interest in the approach. With Sillett and Pesendorfer, the National Park Service hopes to tap Smithsonian Scholars for a study with California Scrub-Jays on the margins of the scar from last year鈥檚 , which charred 100,000 acres. About a fifth of that is on park land within the Santa Monica Mountains National Recreation Area, where unnaturally frequent and intense fires have raised concerns about a surge in invasive species. In a vicious feedback loop, that will lead to yet more frequent and intense fires, possibly converting whole ecosystems. The statewide story isn鈥檛 rosy, either: Total annual area burned has increased five-fold over the past five decades, likely driven by warmer temperatures drying out vegetation.

But even if using jays to speed the recovery of such places doesn鈥檛 prove cost-effective, Sillett says, its utility to students remains: It reveals the deep interconnectedness of living things and the myriad ways they sustain each other, made visible in a shower of seeds and a flash of blue feathers.

This story originally ran in the Winter 2019 issue as 鈥淐orvid Conservation Corps.鈥 To receive our print magazine, become a member by .鈥