Driving up and down the streets of Los Angeles, ornithologist Dan Cooper searches for evidence of hawks’ nests. But he doesn’t scan the trees. He gazes at the asphalt, where the white tones of a hawk’s poop, also known as whitewash, stand out perfectly. “We drive slowly and look for a big splatter of quarter-sized, chalky whitewash,” he says.
Before he began studying how and where L.A.’s raptors build their nests, Cooper gave little thought to bird droppings on the streets. “We’ve all seen bird shit on the ground,” he says, but it sort of fades into the background. “It makes you wonder, What else are you missing?”
These birds of prey, on the other hand, don’t miss much. Spending his days watching raptors go about their days, Cooper has been struck by how attentive they are to their surroundings. He suspects that they have figured out how to survive among millions of bipedal primates—us—through careful observation. They’re not just scrutinizing the crows and the squirrels. They’re also watching us. Bird-watching, in other words, goes both ways.
Ornithologist Dan Cooper and science writer Jason G. Goldman join Alta Live on Wednesday, February 24 at 12:30 p.m. Pacific time.
Indeed, these animals spend their lives becoming attuned to the rhythms of their territories. They know the dog walkers, the gardeners, the letter carriers. They know when Mom and Dad get in their cars to go to work each morning, when the kids come home from school, when lights get turned off as people settle into their beds for the night.
The raptors that can make it in the big city are soothsayers. They can forecast the future, at least well enough to get by. “It’s a rhythm of being that depends on predictability,” says Cooper. “Their survival is based on their ability to predict normalcy and routine,” or, to put it in more scientific terms, to detect statistical regularities. And, he adds, that’s true for humans as well. “We’re just like all the animals because we came from them. They’re not similar to us; we’re similar to them.”
Yet in March, our understanding of the statistical regularities of our own ways of life was turned upside down, almost in an instant, when the COVID-19 pandemic ripped through our communities. We now find ourselves in a space where our intuitions fail us, where we can no longer predict with any reasonable certainty what will happen.
Perhaps the disorientation we all feel is something like what happens to a raptor when a tree gets cut down, or a hillside is developed, or the rats and squirrels its species spent centuries preying on are suddenly full of toxic rodenticide. Or when a quiet corner of wilderness suddenly becomes a playground for the no-longer-quarantined. But there’s no use searching for a missing tree. For a raptor, it’s adapt or die.
DEATH FROM ABOVE
A hungry Cooper’s hawk will perch stone-still on a tree branch until it spots a pigeon or a sparrow flitting by. Then, in a flash, it will dive and snatch its hapless prey. Everything about a Cooper’s hawk has evolved for stealth and for speed. The bulkier members of the species weigh just over a pound and have an average wingspan of almost three feet. Known as accipiters, Cooper’s have trim bodies, long tails, and short wings that allow them to swerve and bank and even round tight corners. Unlike red-tailed hawks and turkey vultures, their larger cousins that soar above undeveloped hillsides or manicured lawns looking for something to eat, Cooper’s hawks don’t glide. They are aerodynamic ambush predators.
The survival skills that Cooper’s hawks have refined over centuries of nesting and foraging in untrammeled forests with lush, dense canopies are precisely what enable them to thrive in urban areas. “Cooper’s like gallery forests, linear forests along a waterway where they can zoom through the canopy,” says Cooper (no relation to the bird). “Urban canyons,” he adds, meaning the rows of houses with their lines of trees on either side of asphalt-coated roadways, “are, I suspect, an analog.”
Written records for birds in the L.A. area date back to the late 1800s. At that time, grizzly bears still gobbled up berries in the Santa Monica Mountains, and citrus orchards had started to replace grasslands. At the eastern end of the mountains, an area of 4,200 acres now called Griffith Park would have provided a suitable nesting habitat for nine types of raptors—the family of birds that includes vultures, eagles, owls, and hawks—Cooper’s hawks among them.
Four years ago, the nonprofit research, advocacy, and education group Friends of Griffith Park hired Cooper to survey the nesting raptors within the park boundaries. The study area has since expanded to include the rest of the eastern Santa Monica Mountains, up to the 405 Freeway, plus large swaths of the San Fernando Valley and the Los Angeles Basin.
Cooper brought on wildlife biologist Courtney McCammon, who had conducted a similar survey in Irvine. Together, the pair enlisted dozens of volunteers to help find and monitor nests. They frequently find red-tailed hawks, red-shouldered hawks, Cooper’s hawks, and great horned owls. There are other raptors, too, like peregrine falcons and American kestrels, but they are fewer and farther between.
“Nature is not only in Yosemite; it’s also here in town, in your yard,” says Cooper. “Even though you think of your neighborhood as a place to walk your dog or park your car, it’s actually being used a lot by wildlife.” And, as the researchers are learning, each of the different types of raptors has its own ways of using the neighborhoods surrounding Griffith Park.
Cooper’s hawks nest almost exclusively in trees, but last year survey volunteers found only a single pair using a native oak, in Franklin Canyon Park. The rest made homes in introduced, ornamental species: shamel ash, London plane, even the jacaranda, with its purple flowers and unmistakable scent of leather and horse poop. Because Cooper’s hawks feast mainly on small birds, they can eat well just about anywhere, even miles away from the nearest bit of wilderness.
Red-tailed hawks, too, seem to prefer nesting in newcomer species. Most use non-native pines or eucalyptuses, though the truth is, they will nest in or on almost anything: tall trees, cliffs, rocky outcrops, or even utility poles. One pair this year built a nest of twigs on the 12-story-high window ledge of an office building near Koreatown. “Red-tailed hawks really need these big patches of open space,” says Cooper. “Almost all our nests of red-tails involve trees at the urban-wildland interface,” or what wildlife biologists refer to as edge habitat, such as where developed neighborhoods butt up against undeveloped hillsides or, in the case of the Koreatown pair, a really big irrigated lawn.
Cooper and McCammon have found that Cooper’s hawks are abundant in the valleys and basins of Los Angeles County, with pairs establishing territories measuring roughly a square half mile; that red-shouldered hawks still somehow eke out survival in the city but seem more common in such areas as the Arroyo Seco, Beverly Glen, and Studio City, where there is—or once was—a natural spring, artesian well, or other aquatic habitat; and that despite the constant “plant native species” drumbeat from wildlife advocates, hawks don’t really appear to prefer them.
These insights call into question some ideas about the urban forest. “Los Angeles, unlike cities in the eastern half of the U.S., isn’t a degraded version of a forest, where houses have replaced trees. The urban forest in L.A. is a whole novel ecosystem. There’s no natural forest of shamel ash trees and palms and junipers and Aleppo pines that L.A. displaced,” says Cooper.
Once upon a time, Los Angeles was a Mediterranean Serengeti: scrubby grasslands and prickly chaparral dotted with the occasional coast live oak. According to L.A.’s Urban Forestry Division, the area is home to some 10 million trees, and their pedigrees are as diverse as the people who drive past, walk by, and picnic beneath them—palms and pines from the Canary Islands, carrotwoods and eucalyptuses from Australia, coastal coral trees from South Africa, deodars from the Himalayas, cypresses from the Mediterranean, ginkgoes from China—even while relentless development and the silent march of climate change erase native chaparral and coastal sage-scrub ecosystems.
“What does conservation mean if you’re starting from a wholly artificial point? Is it still conservation?” asks Cooper as we sit together, eight feet apart for social distancing, in his Ventura County backyard under smoke-filled skies and in the shade of an Aleppo pine. “It’s more like coexistence than conservation. Because we’re not really conserving much. It’s not like Cooper’s hawks are declining and we’re saving them. We’re learning about how they coexist with people.” Or, in some cases, how their intuitions lead them astray.
Emily Underwood
A BIRD’S-EYE VIEW OF LIFE
Gerry Hans, president of Friends of Griffith Park, won’t say exactly where he spotted them, but it was the morning of April 8 when he noted a pair of peregrine falcons on the wing within the park. It was closed to visitors owing to the pandemic, but he had special access to continue monitoring raptor nests for the study.
“I was very excited,” Hans recalls, because by the first week of May, he’d confirmed that the pair had constructed a nest on a cliffside and were incubating eggs. It was the first time in modern history that the fastest birds in the world had attempted to start a family within Griffith Park.
Then, on June 3, after the park had reopened, Hans spotted rock climbers just a few feet from the chicks. “I went back just a couple of days later,” he says. “Nothing.” He suspects it was the closure that led the falcons to believe the park was safe for nesting—and the subsequent influx of visitors that drove them away.
Most wildlife stories end with directives for living a more critter-friendly lifestyle. But when it comes to these raptors, we just have to get out of their way. “These hawks are here because of what we’re doing; we’re already making life appealing for them,” says Cooper. If we can avoid poisoning their food with rodenticides, and if we can put off tree trimming until after the breeding season, if we can give them some space while they’re nesting, it seems they’ll do just fine.
“Both hawks and humans have to be resilient in the face of changes,” says Nurit Katz, a survey volunteer. As those Griffith Park falcons and the rest of us have learned, all the statistical regularities in the world can’t account for the statistically rare: the reopening of a park that’s been closed for months, or the outbreak of a highly contagious, deadly virus. That’s where flexibility—and a sober outlook—comes in. Especially as our public health crisis gives way to the more pervasive, longer-lasting climate and biodiversity crises.
“It may be that getting to know these raptors, seeing the city and life through their eyes, helps you deal with your own mixed-up-ness right now,” says Cooper.
Katz agrees. “At a time when I was otherwise quite isolated, I appreciated having the company of the hawks. It was hopeful to be able to see these hawks nesting, and the little nestlings,” she says. “It was helpful to see those signs of new life.”
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