| The Magazine of the CALIFORNIA ACADEMY OF SCIENCES |
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Feature Soaring with the Hawks
Five humans, one bird, all heading south. The bird, a broad-winged hawk, a species the guidebooks say shouldn't be found in California, is businesslike but unhurried, following the coastal mountains, catching thermals and gliding, flapping its wings only when necessary, saving energy for the 6,000 miles it has to go to reach wintering grounds in South America. The humans, one or two to a car, and each car 50 miles or more from the next, are volunteers from the Golden Gate Raptor Observatory. They are far less decorous than the bird. Feathers ruffled, eyes wild from haste and lack of sleep, they wrestle with road maps to figure out where they are on the ganglia of freeways and county roads, poke strange radio antennae out the windows to figure out where the bird is, search the maps for mountain peaks with roads up them where they can get clear radio signals, shout suggestions over the road rumble as to how to get ahead of the bird, stop to call each others' pagers and leave messages about where they are, where the hawk is, and where they're going, then jump back into the cars and continue this strange migration. The broad-wing Buteo platypterus had been caught on a hill overlooking the Golden Gate Bridge, fitted with a radio transmitter, and released. By following the bird, the volunteers hoped to learn what route it took, how it spent its time, and what habitats it required along the way. The hawk roosted the first night in a tree north of the bridge. In the morning, it rose and flew south, and the volunteers, one on Mt. San Bruno, two on San Pablo Ridge, and two on Highway 101, listened to the pinging of their radio receivers, guessed where the hawk was headed, got into their cars, and drove. The second night the bird roosted in a tree off Highway 152 near Pacheco Pass and the volunteers bedded down at a nearby motel. On the third day, Bill James scrambled to the top of Questa Ridge, north of San Luis Obispo, thinking he was ahead of the bird, scanned north with his radio antenna and heard nothing, turned around and heard the signal pinging away over the blue-hazed ridges to the south. On the fourth day, Karen Scheuermann heard it west of her as she drove down into the Los Angeles Basin. The next morning, Alan Harper looked up and actually saw the hawk over the Red Hill Golf Course in Rancho Cucamonga. Scheuermann heard it pass close by her on Mt. San Jacinto, and late in the day Harper drove up Mt. Palomar and got its signal from far to the south. On the sixth morning, James was on a hill above Tecate, Baja California, as the broad-wing soared confidently off over Mexico, where the volunteers knew neither the roads nor the language. The exhausted humans turned back north, exhilarated at having shared a sliver of this unexpected bird's incredible journey. Something about hawks leads people to extraordinary efforts to see them, to peer into their world, to try to peel away the layers of mystery that surround them. There is much mystery. Hawks are big and sharply defined, and their flight is distinctive and arresting to the human eye. But they're predators, which means they are seldom gregarious and they spread out over the landscape so that we don't see a lot of them. They're apt to soar by so quickly that we only get a glimpse. Or they'll sit sullenly for hours in a tree, and we, bored by the lack of purposeful motion, move on. Like most predators, hawks are relatively intolerant of humans, so if we try to pry too closely, they simply depart, leaving us alone to ponder the nature of a world that creates such phantoms. Humans have traditionally filled in the mysteries with big thoughts. The soaring flight and large eyes of hawks gave humans a sense of greater vision, not just of details a long way off, but of things beyond us, of layers in the cosmos we don't see. The Egyptians regarded hawks as divine emblems. The Aztecs of Mexico looked upon them as messengers from the gods. The Ainu of Japan, the Pueblo of the American Southwest, and the Maidu of California all kept eagles and sacrificed them to send their prayers to heaven. As the Ainu sacrificed such a bird, they chanted, "Thou does not belong to this world, for thy home is with the creator." Science has been slow to displace this older view. Because they are shy and mobile, hawks are hard to study. Only recently has radiotelemetry made it possible to follow a hawk for days. But because hawks have limited economic impact, there has been little funding available for research. Much of what we know about hawks has been learned by volunteers like James, a retired Pacific Gas & Electric manager, Scheuermann, who works with the Environmental Protection Agency, and Harper, a biologist who became a computer programmer after finding that, "You don't get paid for wildlife work." Harper explains, "It's a way of keeping my hand in biology." James says, "I like driving on dirt roads. I like finding out the mystery." Volunteer efforts began in the 1930s, in response to the shooting of thousands of birds, with establishment of hawk observatories at Hawk Mountain, Pennsylvania, and Cape May, New Jersey, where hawks clustered on fall migrations and volunteers made annual counts. While counts at such isolated stations can't give overall population figures, they can suggest population trends. Rachel Carson used counts from Hawk Mountain as evidence that DDT was reducing bird populations. In the fall of 1972, ornithologist Laurence Binford was watching hawks out his window at the California Academy of Sciences in San Francisco, when it occurred to him that there must be a place nearby where landforms and weather patterns concentrated hawks as they migrated. He knew hawks did not like to fly over water because there are no thermals to buoy them up and let them soar, and they must flap their wings, spending energy that might prove the difference between life and death in a cold spell or passage through a prey-poor land. He got out his topographic maps and guessed that migrating hawks might be drawn down the Coast Ranges by the winds rising off their slopes, and saw that at San Francisco Bay the Coast Ranges narrow down into the Marin peninsula, just across the Golden Gate. He guessed that the Marin Headlands might be his hawk highway. Sure enough, in three hours he counted 150 raptors of at least ten species. Hawks had evidently been crossing the Golden Gate centuries before humans thought of spanning it with a bridge. As Binford continued to watch, word spread. By 1977, when the Marin Headlands became part of the Golden Gate National Recreation Area (GGNRA) the site was drawing increasing numbers of birdwatchers. In 1981, Carter Faust, a retired schoolteacher, took part in an Audubon Society field trip and was bothered by his inability to identify raptors. Most fall migrants are immature birds and their plumages are considerably different from those of adults. Not only that, many species have a variety of adult plumages. Red-tailed hawks (Buteo jamaicensis) can appear chocolate brown to nearly all white as they pass overhead. Hawk watchers learn to identify raptors by shape and flight mannerisms. Faust started going up Hawk Hill almost daily until he became quite adept at identifying hawks. Other volunteers joined him. In 1983, National Park Service biologist Judd Howell, convinced that banding studies would help understand the migration, teamed with falconer Will Shor to start the GGNRA's volunteer banding program. Two years later, Allen Fish, a young biologist, was hired to coordinate hawk-banding in the Headlands. Faust and Fish were working the same hill, one counting, the other banding, and they thought of joining the operations into a raptor observatory, manned by volunteers. With funding from the Golden Gate National Parks Association, support from the National Park Service, and Fish as Director, the Golden Gate Raptor Observatory (GGRO) was formed. Today, it is the preeminent hawk watch in California, with 250 volunteers. Since 1988 they have banded more than 11,000 birds. Last year they counted 28,000 hawks. Since the 1970s, volunteer hawk-watching activities have grown up and down the state. Peter Bloom, a private biological consultant in Orange County, started banding raptors and watching their nests in 1970, and still bands as many as 700 a year. He is currently watching a female red- tailed hawk he banded as a nestling 25 years ago and a red- shouldered hawk that is 24. Volunteers at the University of California at Davis' Raptor Center do year-round road surveys to keep track of raptor population trends. Watchers at the Kern River Research Center recently documented a fall migration of 32,000 turkey vultures (Cathartes aura) through the hills of the southern Sierra. There has been, too, a smattering of government-funded activity. Joe DiDonato, wildlife biologist for the East Bay Regional Parks District, bands peregrine and prairie falcons and closely watches hawk populations in those parks. Grainger Hunt and Brian Walton of the Predatory Bird Research Group at the University of California at Santa Cruz, studying effects of wind turbines on raptors, have recently documented the densest nesting population of golden eagles (Aquila chrysaetos) in North America--more than 100 pairs in the Altamont Hills, 40 miles from downtown San Francisco. The results of all this watchfulness has been a developing sense that California is an unusually rich wintering ground for raptors and a place of complex and varied migrations. As winter approaches Canada and the Pacific Northwest, the insects vanish, the songbirds leave, the mice and ground squirrels go underground, and the birds of prey that feed on such creatures in summer head south. Many stop in California, where wintering songbirds thrive and rodents forage above ground. Hawk-watching is centered on the fall migration. Then, there are three kinds of migrants. The first are birds which have bred locally. Most of them are thought to wander after nesting season is over, and return to their territories by late winter. Those young birds that survive their first winter also tend to return to their parents' territories. Bloom's studies suggest most red tails nest within ten miles of their birthplaces. After breeding, each species has its own destinations. Bald eagles (Haliaeetus leucocephalus), for example, migrate north, sometimes as far as Alaska, then gradually work their way back south to their nesting territories, following the fall salmon runs, which come earliest in Alaska, latest in Oregon and California. Cooper's hawks radio-tagged at GGRO have headed east, or north into the Mendocino National Forest, then probably circled back to their nesting grounds by December. Even within a species there is bewildering variety of flight paths. Bloom has banded thousands of hawks in a 300-square-mile study area that includes Camp Pendleton and the Irvine Ranch: a few of his red-shouldered hawks go as far as San Luis Obispo, and some of his red-tailed hawks have gone to Oregon, Idaho or Utah, but others seem to stay close to home. Second are winter visitors from the Sierra, northern California, the Pacific Northwest, or prairie states where freezing temperatures deprive them of prey. Rough legged hawks (Buteo lagopus) breed in Arctic tundra but winter in California. Harlan's hawk, a chocolate-colored varient of the red-tail, breeds in Alaska but winters in the Central Valley and southern California among the pale-bellied red- tails that comprise most of the local breeding population. Third, there are long-distance migrants like Arctic peregrines that pass through California on the way to wintering grounds in South America. Brian Walton, whose work was instrumental in the restoration of peregrine falcons (Falco peregrinus) in California, has observed these birds among locally breeding peregrines and visitors from the Pacific Northwest and the Sierra Nevada, and theorizes that because the Arctic birds are just laying their eggs when California birds are fledging, they arrive late and, less able to compete for winter habitat, are forced to leapfrog over local populations. And at least one species leaves the state in winter. Swainson's hawks (Buteo swainsoni) breed in California but make a prodigious migration to Argentina each fall. Gathering in flocks and often joining larger clusters of broad-wings as they move south, they sometimes form spiraling kettles of thousands of birds as they ride the thermals over Central America. They change their diet as they migrate, feeding chiefly on rodents in California's Central Valley but on insects in the pampas. Bloom likes to imagine the vast flocks feeding on dragonflies as they wheel lazily south over the Amazon Basin. Most of the winter visitors to California are juveniles. At inland observatories like Pennsylvania's Hawk Mountain, about half the birds are adults, but at coastal stations such as the Marin Headlands, 80 to 90 percent are juveniles. No one knows why. One theory is that the direction of the first migration is inborn, but adults, having made a journey or two, acquire the ability to find routes with better wind and prey. Fish believes some wintering areas are occupied chiefly by adults, and these seem to him to be the spots with the best advantages for breeding, for example the best nesting trees. Though they are less territorially rigid in winter, adults tend to harass young birds and young birds tend to avoid conflict with adults. Harper says, "I think a lot of the birds are looking for a place they can stay the winter without getting kicked out." For a young hawk, life's challenge is finding the promised land--a territory of its own where it can hunt and breed. It is akin to a human finding work, love, and community. With more hawks than homesites, there is much strife as young birds search for unoccupied territories. In one Alaskan study, half the mortalities among bald eagles were due to competition for territories. No one knows how a hawk decides where to wander. They do follow hill and ridgelines where the thermals keep them aloft. They do seem to turn up where prey is most abundant. Two Cooper's hawks (Accipiter cooperii) were radio-tracked to the same valley in the Mendocino National Forest. Says Harper, "It's a tiny valley but full of songbirds [the chief prey of Cooper's hawks] in winter. It just looked like Cooper's hawk heaven." In 1996, the Marin Headlands had both an unusually dense population of mice and an unusually high count of red tails. No one has yet been able to follow an individual bird long enough to get a complete picture of its winter travels. We can't say for sure whether a red-tailed hawk finds one place to spend the winter or keeps moving around. "We don't really know where they go in general," says Scheuermann. "Most of our radio-tagged red- tails went south; but band recoveries show they also go east. I still don't think we have the whole picture." So, the volunteers keep counting, banding, and radio- tagging, hoping to unravel more secrets. They are likely to say they do this because it will establish baseline data against which to understand future hawk population declines, and so to help conserve raptors. But, clearly, it goes deeper than that. People are drawn to hawks in ways they aren't drawn to other creatures. Says Jim Estep, a former Department of Fish and Game biologist who has long studied Swainson's hawks, "Among raptor biologists there is a tradition of intensity and passion that you don't find among other wildlife biologists." GGRO volunteer Quentin Goodrich last year monitored 70 different nests to try to collect data on clutch size and nesting success rates; at each location he might peer for hours through a spotting scope to determine whether a colored blob in a distant nest was a leaf or a chick. He says, "It's very time consuming," and adds wistfully, "If I didn't have a job, I could really cover the area." Other GGRO volunteers will devote their entire vacations to banding or counting or radio-tracking. Says Joe DiDonato, "They're drawn to the raptors the way the birds are drawn to the place." Every August DiDonato himself is drawn by some pull he cannot name to climb Hawk Hill in the Marin Headlands, even though he knows hat most of the hawks will not arrive for another month. Allen Fish explains it in terms of surviving the urban area. He believes, to overcome our own density and shrillness, we have to find ways to recall our evolutionary origins in wildness; when we are engaged with hawks, we become wild and healthy again. He tells the story of a woman who, after years of volunteering, drew him aside to explain why she volunteered. A lifelong manic depressive, she had been hospitalized and medicated, but she didn't like taking lithium. At home, she began to follow the activities of a kestrel outside her window, and found it comforting. With the consent of her doctors, she sought to wean herself from drugs with bird study. It took two years, but she did it, and now she counsels others seeking to replace medications with wildness. What is it about hawks that stirs us? Every hawk watcher has an answer: freedom, power, the grace of their flight. But one suspects there is an even deeper meaning, something that reaches back to the tradition that hawks have access to the heavens. It is, says Fish, "the big view, the broad view. I think people climb mountains because they get a broad view of their lives. I'm sure everybody on Hawk Hill who looks up at a raptor is doing a reflective exchange, thinking what it would be like to be up there looking down." What the hawk would be seeing down below is the clash between nature and urbanity--between belonging and alienation. At least some hawk watchers see it this way. For eight years, Dan Gottsegen, an artist, has been a GGRO volunteer bander. He had been painting hawks in some pictures, but those pictures didn't seem right and never left his studio. Then he began to think more about what drew him to the birds. "I've been thinking about diaspora and migration," he says. Each generation in Gottsegen's family has moved to a new place. It's a very California experience, for most Californians have come from somewhere else. "California and the West are particularly rootless," says Gottsegen. "My generation in this country has been trying to find a sense of place." He thinks hawks have that sense of place. "Even though hawks move and migrate and they are above a place, at the same time, they are so much of a place. When you've banded a hawk and are holding it, you're aware that they have a pure intention, unencumbered by doubt." He believes that purity of intention is what a human would have if he or she felt a real connection to place. In many of Gottsegen's paintings, hawks have become emblems of human migration, but in at least one, he has managed to paint this hawkish purity of intention, this sense of belonging. He had a series of dreams that recalled the story of Jacob in the Bible. The story tells how God commanded Isaac to move into a new land, and how, years later, his sons Jacob and Esau contended for his favor. Jacob was sent by his father to Pandamarun to find a wife, and on the way, he slept on the ground, with stones for a pillow. He dreamt of a ladder with angels ascending to heaven and descending again, Rand Behold, the Lord stood above it and said I am the Lord God.... The land whereon thou liest, to thee I will give it and thy seed. And behold I am with thee and will keep thee in all places wither thou goest, and will bring thee again into this land." The way Gottsegen dreamt and painted it, he slept on a pillow of hawk feathers, and those were hawks soaringinto the heavens and diving earthward. And he awoke to hear the voice say, "This will be your place."
Peter Steinhart is the author of The Company of Wolves, Dos Aguilas: The Natural World of the U.S.-Mexico Border, and California's Wild Heritage. |
Fall 1997
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