The effect of DDT on the Coronados Islands pelicans

Future flock

"I'm enthralled by creatures with wingspans so wide that they seem to wobble when they beat."
  • "I'm enthralled by creatures with wingspans so wide that they seem to wobble when they beat."

I’m not sure why the birds on the north island of the Coronados are making such a racket. They're screaming so loudly it seems like the noise should carry to Point Loma, fifteen miles away; the cacophony sounds like the bawling of a hundred angry human infants. From a boat, even just a few hundred feet offshore, the birds blend into the mottled cliff side of the island, a forbidding lump of rock that rises precipitously from the sea. But through binoculars I can see that indeed this is a nursery. Sections of the cliff are virtually covered with fuzzy baby pelicans, snow white, ungainly creatures which have broken out of their shells only days and weeks before. I know they're probably screaming because they’re hungry, or for some equally prosaic reason, but this year. I’d like to believe the pelicans' shrieks arc a cry of victory.

Middle Island, South Island. The Coronados are one of the only places where California brown pelicans are born.

Middle Island, South Island. The Coronados are one of the only places where California brown pelicans are born.

The Coronados are those jagged lumps you see on clear days when you look south out over the ocean, and they 're also one of the only places where California brown pelicans are born. Every spring the birds gather here, and at the Channel Islands off Santa Barbara, and at a dozen other havens scattered along both coasts of Baja, where they perform the ancient acts which perpetuate their species. Chicks usually hatch between March and May and the parents tend them solicitously for three months; by midsummer most of the youngsters have flown off on their own. Great flocks of brown pelicans nested on the Coronados when the first curious San Diegans sailed out to them ninety years ago (before the Mexican government declared the islands to be a sanctuary in 1924). But ten years ago the islands saw an ominously different scene; 1969 marked the pelicans' most silent spring.

Newborn brown pelicans. On the Coronados, the scene was even worse than that at Anacapa: out of 350 to 400 nests, no young survived.

Newborn brown pelicans. On the Coronados, the scene was even worse than that at Anacapa: out of 350 to 400 nests, no young survived.

The large-billed birds flew out to the islands that year and built their nests in the scraggly bushes on the slopes of the southernmost island. As usual, the females had deposited their eggs in the centers of the motley collections of twigs, and the parent birds had prepared to cover them with their four webbed toes (the pelicans' standard method for warming their incubating offspring). But one by one, as they had settled down on the big white spheres, the parents found themselves standing in slimy pools of broken shell and yolk. Most gamely picked up the dripping messes with their beaks and flung them into the brush, only to try with a second and third egg and to fail again. By May of that year, all the adults had flapped off on their annual northern migration, leaving on the island hillsides a biological tragedy.

Joe Jehl still remembers the day in the spring of 1969 when he announced his findings at a press conference at the Natural History Museum.

Joe Jehl still remembers the day in the spring of 1969 when he announced his findings at a press conference at the Natural History Museum.

Though they flew off that year without young, the pelicans had acquired something more exotic—status as a symbol in one of the world’s most dramatic biological controversies. And when they glided northward a decade ago, the birds were also riding something more powerful than the coastal winds. They were riding the currents of a growing environmental movement that was to make the pelicans its early stars.

Brown pelicans on the Coronados. "If pelicans don’t breed now, it’s because people are going into the colonies and bothering them, or because their food supply has disappeared.”

Brown pelicans on the Coronados. "If pelicans don’t breed now, it’s because people are going into the colonies and bothering them, or because their food supply has disappeared.”

Joe Jehl witnessed the beginning of the pelicans' saga, and he recalls that it all began quietly. Jehl is a lean, boyish man with an incongruous head of a gray hair. Today he's San Diego’s most respected authority on brown pelicans, but in March of 1969 he had only an undistinguished interest in the big feathered creatures. Jehl was working then as the curator of birds and mammals at the San Diego Natural History Museum when a Berkeley biochemist and ornithologist named Bob Risebrough invited him to go on a trip surveying pelicans on Santa Barbara’s Channel Islands. Risebrough also invited a U.S. Fish and Wildlife Service ornithologist named Fred Sibley and another Natural History Museum ornithologist named Monte Kirven. Foul weather and the Santa Barbara oil spill postponed the expedition several times, but finally the four men hitched a ride with park rangers from the Channel Islands National Monument and set off for the traditional nesting grounds on March 19, 1969.

Today Jehl works as assistant director for the Hubbs Sea World Research Institute (he was the first scientist to quit the Natural History Museum during its recent administrative upheaval), and he recalls that none of the four biologists began the island trip feeling particularly alarmed. True, all had noted minor warning signals. For one thing, they’d seen Eastern brown pelicans apparently vanish from the Gulf of Mexico, where their numbers at one time had made them the state bird of Louisiana. Jehl also says that a broad survey of seabirds of 1967-68 had counted very few nesting pelicans, but even that didn’t seem cause for undue concern. ‘’There's so much fluctuation in biological systems that one year’s little discrepancy doesn’t get anyone excited, and rightly so," he says. “There was a little uncertainty in everyone’s mind, but nothing you’d want to get excited about. Call it a lingering doubt. ’’ However, when the four scientists sailed around the islands and discovered no signs of nesting, their doubts grew. They finally located one colony on the peak of Anacapa Island. While Jehl stayed in the lower part of the island to survey other types of birds, the other three men scrambled to the summit, where they were greeted by a scene of utter desolation.

“They came back with bags full of these deformed, thin-shelled eggs," Jehl remembers. “And you didn't have to be a very smart biologist to know that something really funny was going on. If you walk into a colony and find a broken egg or two. you can chalk it up to the gulls eating it, or you can think of some simple explanation. But if you walk into a colony and find that just about every egg you see is flat and collapsed and doesn't have any shell on it. . ." his husky voice trails off. “It was incredible. We were stunned."

The group raced back to the mainland and Jehl immediately headed south. In San Diego he grabbed a boat and motored out to the Coronados, where the scene was even worse than that at Anacapa: out of 350 to 400 nests, no young survived. Further south, on Baja's San Martin and San Benito islands, the toll was less dramatic, but still abnormal. Everywhere, Jehl found strange, deformed shells.

Meanwhile, back in Berkeley, Risebrough had analyzed the yolks of eggs collected at Anacapa, and his findings seemed to identify the culprit conclusively. The yolks contained 226 parts per million of DDE (a metabolic product of DDT); fatty tissue within the yolks contained even higher amounts.

At the time of Risebrough’s incriminating discovery, the fortunes of DDT had already slipped drastically. In its youth, however, the pesticide had been gratefully welcomed. Invented in 1939 by a Swiss chemist named Paul Muller, the substance had quickly commanded world attention: it seemed safe, easy to handle and mass produce, and capable of smiting a host of man’s ancient enemies—namely, insects that carried diseases like malaria, epidemic typhus and typhoid fever, and dysentery. In the testing grounds of the Second World War, DDT soon proved itself; before long thousands of soldiers and sailors were dusting themselves and their personal effects with DDT powder as regularly and enthusiastically as teenagers applying deodorant. With the war’s end and the chemical’s general release, the miracles moved to an even broader stage; the pesticide saved countless persons from death and starvation by increasing food production. In 1948 Muller ascended to the halls of the Nobel laureates; by 1950 world health authorities estimated that DDT had saved five million lives worldwide by destroying malarial mosquitoes.

In the face of such wonders, it wasn’t surprising that the first few sour notes struck by the chemical sounded quietly. Yet gradually, over the years, they built to a disturbing refrain. Huge doses of DDT seemed to kill birds and fish as well as insects; and evidence also began to indicate that the intensity of the pesticide magnified as it climbed the food chain. There were several incidents like the one that occurred at Clear Lake, California, ninety miles north of San Francisco. There a 1949 application of DDT killed ninety-nine percent of the gnats, which had plagued out-doorsmen at the lake. Within five years, however, the gnats had returned. A second application again killed ninety-nine percent of the pests, but this time they recovered in just three years. A third application killed less than ninety-nine percent, and then that winter tragedy struck the area. More than 2000 Western grebes, a fisheating water bird which lived at the lake, began to die. Yet mystifyingly, the concentration of the chemical in the water was minute—only .02 parts per million. Then biologists found that plankton in the lake contained ten parts per million of the pesticide, and fish that ate the plankton contained 903 parts per million in their fat. The fat of the meat-eating fish that ate the vegetarian fish contained 2690 parts per million, and by the time the grebes died, their fatty tissues contained 100,000 times the concentration of the pesticide in the lake.

By 1962 the growing body of evidence prompted marine biologist Rachel Carson to release her famous attack on DDT, Silent Spring. The book opened the floodgates through .which anti-DDT data poured. By the time Risebrough, Jehl, and the other two men headed out to survey pelicans in the Channel Islands, studies had already shown DDT to be accumulating in adult pelican bodies, and other work had indicated that shells of eggs from several bird species (including ospreys, Bermuda petrels, bald eagles, and peregrine falcons) had been thinning gradually since the Second World War. So with the discovery of the crushed eggs, the case seemed conclusive—the pesticide was about to claim another feathered victim.

Joe Jehl still remembers the day in the spring of 1969 when he announced his own startling findings at a press conference at the Natural History Museum. He says one reporter from the Evening Tribune showed up and the small story that resulted was buried in the sports pages. But the brown pelicans had more than their share of fans, and concern about their plight soon raced through the popular media. Jehl at least partly credits that concern to an announcement from Robert Finch (then secretary of Health, Education and Welfare) in November of 1969. Finch declared that the federal government would phase out all but “essential uses” of the pesticide within two years.

Finch’s announcement didn’t help the pelicans much the following breeding season, though. Jehl counted only three to five young that year on the Coronados; he found none on San Martin Island and only one on San Benito. Other observers announced that the Anacapa colony had also met with total reproductive failure. Jehl recalls that at that time the scientific community still assumed the pesticide was entering the marine food chain as a result of the tremendous volumes being sprayed on cropland worldwide. “We figured it was coming from agricultural uses, floating through the atmosphere, running off the land, then settling in the sea.” Unfortunately, that theory didn’t explain why brown pelicans on the east side of the Baja peninsula weren’t faring anywhere near as badly as those on the Pacific side. The answer finally emerged in 1970, when a researcher who had been checking DDT levels in sand crabs all along the California coast found that those levels skyrocketed off White’s Point in Los Angeles. The level there peaked at forty-five times that at major agricultural drainage areas. The spot turned out to be near the site of the outlet for the Los Angeles County sewer system. Feeding into it were watery wastes produced by the Montrose Chemical Corporation, the only producer of DDT in the U.S.

If there seemed to be obvious links between the chemical wastes and the sea life languishing off Southern California, they weren’t clear to the chemical company’s Torrance plant superintendent. “Do you have the impression that the brown pelican is virtually extinct?” he scoffed in the Opinion section of the Los Angeles Times in the summer of 1969. “Just south of the border in Ensenada and beyond there are thousands living and breeding normally.” Indeed the pelicans didn’t seem to be disappearing; Southern California residents still could see them soaring along the coast. What they couldn’t sec were the unhatched young. Since pelicans can live for as long as fifteen years, it would have required years of breeding failure for the numbers to begin thinning noticeably. As the controversy quickened, some challenged the notion that DDT had any effect on the reproductive failures. Two San Jose State College biologists, for example, declared that intruding environmentalists had scared the pelicans out of breeding. Nationally, the pesticide’s defenders reached even greater dramatic heights. One spokesman made a point of publicly ingesting the chemical to prove it was safe. Joe Jehl smiles sardonically when he shows off another particularly memorable clipping retained from the days when tempers flared the hottest. “Up With People—And Down With The Venomous Foes Of Chemical Pesticides,” reads the headline from Barron's, the weekly financial journal. “Better things for better living, whether through chemistry or some other triumph of science, rarely make headlines or win votes,” the article flamed. “Without them, however, mankind never would have climbed out of those wondrously natural caves.”

Despite such invective, 1971 came as a turning point for the pelicans. In April of 1970 the Los Angeles DDT plant had begun depositing its liquid wastes in a sanitary landfill, and oceanic input of the pesticide started to decline rapidly. By the very next breeding season, egg shells found on Anacapa, Santa Cruz, and North Coronado islands seemed noticeably thicker, although only forty-two babies developed that year from 650 nests counted. The political climax to the saga came on June 14, 1972, with an order from William Ruckelshaus, head of the Environmental Protection Agency. He overturned a recent decision of a federal hearing examiner that DDT’s benefits outweighed its risks, and he ordered a virtual ban on the pesticide in this country.

And then the pelicans surprised everyone. Jehl states, “We had thought they had so much DDT in their systems that it might take 'em ten years to get rid of it, and by that time these birds, which hadn't bred in three or four years, were going to be so old and senile that they couldn't breed anyway. We had thought the whole damn population might just go!" But the egg shells almost immediately thickened, and the numbers of surviving young climbed correspondingly. In 1973 observers counted 134 chicks produced from 597 nests on the three breeding islands (Anacapa, Santa Cruz, and North Coronado), and by 1974 an astounding 1185 young birds appeared to have survived.

Now Jehl stands on the flying bridge of a borrowed yacht trying to survey a breeding colony which this year may even exceed that bumper crop of 1974. So many birds cover the face of this North Coronado Island cliff that counting them boggles the untrained mind. Jehl and a young assistant naturalist follow an old established procedure. As the captain inches his vessel northward, the two biologists freeze, binoculars locked at eye level. Mentally, they stake off sections of the brush-tangled, guano-covered slopes. They count, silently and frantically, then they periodically lower their glasses to blink hard and call out the numbers over the avian din. “There’s birds nesting in the ground this year. In the grass,” Jehl mutters incredulously. “Christ, there’s a mess of chicks.”

The sea is calm this morning, but the boat still bobs slightly. It complicates the counting, but this early in the nesting season Jehl has no alternative but to do it from the water. Normally no one sets foot on these island sanctuaries except for rare scientific parties and a small group of villagers on the south island. Jehl, in fact, holds a precious landing permit for this expedition, but even he won’t venture onto the north island at this delicate time. He explains that one pelican parent must stay with each nest at all times to protect eggs and chicks from marauding gulls and to shelter the tiny chicks from the sun. Humans entering the colony would scare away the parent birds. “One person in a pelican colony for ten minutes can be enough to destroy the colony for the year, ” the ornithologist says. So he settles for the rough count from the boat.

From the offshore vantage, he can’t see the thickness of the shells, but Jehl knows they have remained at normal levels since 1974, even though the success of the pelicans’ breeding has fluctuated since then. Last year, for example, Jehl counted only sixty-two chicks produced by 265 pairs on the Coronados, but he says natural forces are now causing those fluctuations. He laughs when he mentions that pelicans still officially perch on the endangered species list. “They’re not endangered today, not by any stretch of the imagination. They were endangered because of DDT. Now, they do have problems today because they’re dependent on anchovies, and the anchovy population has some competition from bait boats. But if pelicans don’t breed now, it’s because people are going into the colonies and bothering them, or because their food supply has disappeared.”

Jehl’s pronouncement disturbs me. Despite the pelicans’ remarkable comeback. I’ve found myself wondering about its significance. I know what difference the pelicans' survival makes to me personally. Quite simply, I think San Diego is more beautiful because of them. I'm enthralled by creatures with wingspans so wide that they seem to wobble when they beat; who glide low and heavily and smoothly like elegant patrol planes; who can climb so effortlessly and then drop like stones to the water surface, creating splashes so huge that each dive is a separate comedy. But apart from aesthetics, I wonder if it would have made any real difference to our human lives if pelicans had simply vanished from the globe? And how important was their victory over the threat from a chemical pesticide if they’ve only survived to face threats from human disturbances and dwindling food supplies?

Jehl, glib and fast-talking, retorts that it wouldn’t really make much difference— environmentally—if all the brown pelicans vanished this instant. He argues that what was important about the saga of the brown pelicans was not the “victory” of one individual species, but rather the defeat of an agent that threatened an entire wildlife habitat. “All animals go extinct!” he cries. “All individuals die. All species die. Even man some day will drop off the face of the earth. Who really cares? I don’t care, except as a biologist I care that the process that makes species is allowed to continue. ”

Jehl complains that this is where the environmental movement has gone wrong. “We get so terribly concerned with little dickey birds and snail darters and we lose sight of the big picture.” He worries that such narrowness may ultimately defeat environmentalists. “I don't think that the species-based approach is a sound biological approach. I think it's absolutely self-defeating because it gets you into situations like what you’ve got with Tellico Dam and the snail darter. Put the dam and the snail darter up to a vote, and nine-to-one the public will say build the dam— who cares about the snail darter?— because we’ve built this fight on one silly, insignificant fish, which if it drops off the face of the earth tomorrow really doesn’t make any difference.”

In contrast, Jehl argues that what’s important is “to protect major chunks of habitat, because then the species that you’re worried about do just fine.” He says that the contrary—worrying about individual species rather than habitats— leads to dilemmas like the one now involving the California condor. Only a handful remain in the wild, but condors probably could be raised in captivity. Jehl says the question is, “Should we spend millions of dollars catching these birds, putting them in captivity, and raising them? Do you put a lot of money into saving this species so that what you have is condors in captivity? How much money would you pay to see a dinosaur?” he asks flippantly. Then he answers his own question, half seriously. He says maybe it’s worth a lot to people, so maybe we should have dinosaurs—or condors—in captivity. But there’s one thing to remember. “Even if we become hip-deep in condors, there ain’t no place you can put them in the wild ever again. There's no chance that they could ever be released into the kind of habitat they need, because there is no such place in the world any more!”

The banning of DDT preserved a habitat that ultimately affected dozens and maybe hundreds of species; a habitat so large and crucial that it ultimately may have affected man’s survival. (Evidence even had been gathered indicating that the chemical decreased photosynthesis in plankton, the primary source of the world’s oxygen.) Jehl says it was a victory for the preservation of basic biological processes. “What bothers me is that the processes ought to be able to go on at a rate at which animals can be tested. Environments change and dinosaurs went extinct. We don’t know why they went extinct, except that basically what happened is that they weren’t able to cope with what happened in their environment. They couldn’t make it. I don’t care about that. But if you put DDT in and the animals have a ten-year life span, they don’t have a chance to develop resistance to that. And it seems to me that our role as biologists—or just as inhabitants of the earth—is to make sure that the changes we are inflicting on the world don’t come at a rate that doesn’t give the animals a chance to cope.”

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